APPARATUS, METHOD, AND DISTRIBUTION SYSTEM FOR PREVENTING ELECTRIC SHOCK AND FIRE DURING CURRENT LEAKAGE AND GROUND FAULT

Abstract

A device for preventing electric shock and fire according to the present invention includes one or more fault detectors having one end electrically connected to at least one of two or more earth-isolated power lines with a resistance value greater than or equal to a predetermined earth resistance value and a first neutral point having a potential between the voltages of the two or more power lines, and the other end electrically connected to earth, wherein the fault detector detects a leakage current by forming a current path for the leakage current flowing from the two or more power lines or the first neutral point to earth.Therefore, according to the present invention, by detecting a leakage current between a power line, which is insulated from the earth and supplies power, and the earth, limiting the detected leakage current, which is a dangerous or lesser current, or cutting off the flow of leakage current in a human body or peripheral installations, it is possible to prevent electric shock and the occurrence of fire during the leakage current.

Description

The present invention relates to a device, method, and distribution system for preventing electric shock and fire during current leakage and earth fault, more particularly to a device, method, and distribution system for preventing electric shock and fire during current leakage and earth fault with the ability to prevent electric shock and fire caused by current leakage by detecting a short-circuit current leakage between a power line, which is insulated from earth and supplies power, and earth, to limit the detected leakage current to a dangerous or lower current or to cut off the leakage current flowing into a human body or peripheral installations. BACKGROUND OF THE INVENTION In general, electrical installations refer to a transformer, an electrical cable, a switch, a circuit breaker, a distribution box, an outlet, a control panel, a switch, and other auxiliary installations of a switchboard, which is a power receiving installation, for electrical equipment, and includes electrical installations for electrical businesses, electrical installations for general use, electrical installations for private use, machinery and equipment (loads) installed for use by electricity, and the like. In order to connect these electrical installations, for example, a four-wire three-phase electrical installation supplies power by connecting a neutral line (NL) and power lines, which are a plurality of conductors (phase-R, phase-S, phase-T), using methods such as Y-connection, Δ-connection, and Y-Δ-connection. Here, when the four-wire three-phase electrical installation is connected to a load, if one conductor (power line) and another conductor (power line) are connected, the four-wire three-phase electrical installation is converted from 380V, and when one conductor (power line) (e.g., phase-R) and a neutral line (NL) are connected, the four-wire three-phase electrical installation is converted from 220V to supply power to a single-phase load. In principle, the neutral line (NL) should have zero potential, which is ground potential. However, in reality, when the phases of each phase are not exactly 120° apart in the field, the neutral line (NL) can have a small voltage. In this case, when the neutral line is connected to a ground line (which is a ground potential line), the potential of the neutral line is maintained at zero because it is in contact with the ground. Even if the phases of each phase are slightly different, the neutral line maintains zero potential. A single-phase distribution line uses two wires. One wire is connected to a neutral line that is equipotential with earth, and the other is connected to a plurality of conductors (power line) with a potential difference of 220V from earth. When a current leakage (ground fault) occurs in a plurality of conductors (power line), there is a high risk of death due to electric shock or fire. However, when the neutral line is not grounded, even if a current leakage, ground fault, etc., occurs, a conductor may not detect it. This increases the potential of a phase where there is no fault, and therefore, a larger accident can occur due to the breakdown of equipment insulation, etc. Electrical accidents can occur when a voltage spike, such as a load or lighting voltage, is introduced. Furthermore, when a neutral side power supply line to which a single-phase load is commonly connected is disconnected, an abnormal voltage is introduced into a light load due to unbalanced loads across a neutral line commonly connected to unbalanced single-phase loads connected to different three-phase phases. This causes electrical equipment to overheat and burn out, frequently resulting in a fire. Image harmonics introduced into the neutral line also cause an abnormal overcurrent to flow through it, leading to electrical accidents. To prevent electrical accidents, a circuit breaker for the wiring and a leakage current circuit breaker are installed. However, electrical fires occur every year without decrease. Since low-voltage consumer electrical installations are generally less reliable than those of high-voltage consumers, most electrical fires occur in low-voltage customer installations. Due to the prevalence of electrical fires, when electricity is supplied on a distribution line with a disconnected neutral, phase loss, improper wiring, an abnormal voltage such as a surge, or an electrical fault such as increased resistance or a poor connection (arcing) occurs in customer electrical installations, low-voltage customers are unable to take corrective action. Consequently, an abnormal voltage is introduced into the loads, or the electrical installations overheat and burn out, resulting in electric shock and fire. Furthermore, blind spots where an electrical fault such as a current leak cannot be monitored range from an entrance receiving electricity from a low-voltage customer building to a distribution switchboard where a circuit breaker is installed. When current leak and ground fault accidents occur at these blind spots, there is no countermeasure, resulting in property damage and personal injury due to electric shock and fire. When a current leakage or ground fault occurs in the power line, and therefore the leakage current flowing from the power line to the ground passes through a human body, an electric shock accident occurs, and when the leakage current flows through peripheral installations or flammable objects, a fire may occur, and therefore, a serious electrical accident may occur. Specifically, an electric shock accident that directly damages the human body occurs when a current flowing from one phase of a power supply passes through the human body, affecting other phases or ground. When the electric shock current flowing through the human body is dangerously high, injury or death can result. In the case of electric shock accidents, it is generally known that when the current flowing through the human body reaches 15 mA or more, convulsions (pain) occur, and when the current reaches 50 mA or more, death results. Therefore, to prevent electric shock accidents, electrical installations and distribution lines must be configured so that the electric shock current is 15 mA or less, which is the dangerous current, or preferably 8 mA or less. In the case of current leakage or earth fault, electric shock and fire accident due to current leakage can occur when a part of the human body or flammable object comes into contact with one or more phases of a bare contact line or outlet, or a leakage current caused by the flooding of a power line, terminal block, or electrical installation flows into the earth through the human body or flammable object. However, the existing circuit breaker to cut off leakage current due to earth fault or leakage current operates only when the leakage current must be a predetermined value or more even if the earth fault or leakage current occurs, and therefore, the leakage current is detected, or has a limit to fundamentally prevent electrical accidents caused by leakage current since electric shock or fire can occur due to even a small amount of leakage current even if the leakage current is limited to the dangerous current or less. BRIEF DESCRIPTION OF THE INVENTION Technical problem The present invention provides a device, method, and distribution system for preventing electric shock and fire from leakage current and earth fault, with the ability to prevent electric shock and fire caused by leakage current by detecting a leakage current between a power line, which is insulated from earth and supplies power, and earth, limiting the detected leakage current to a dangerous or lower current, or cutting off the leakage current flowing into a human body or peripheral installations. The objects of the present invention are not limited to those mentioned above. That is to say, other objects not mentioned may be clearly understood by those skilled in the art to whom the present invention belongs from the following description. Technical solution In a general aspect, a device for preventing electric shock and fire includes: one or more fault detectors having one end electrically connected to at least one of two or more power lines isolated from earth with a resistance value greater than or equal to a predetermined earth resistance value and a first neutral point having a potential between the voltages of the two or more power lines, and the other end electrically connected to earth, wherein the fault detector detects a leakage current by forming a current path for the leakage current flowing from the two or more power lines or the first neutral point to earth. Each fault detector may include a current detection unit that limits leakage current to a predetermined or lower dangerous current, and detects leakage current and emits a detection signal. Each fault detector may also include a unidirectional current unit that limits the path for leakage current so that the leakage current flows through the current detection unit in a unidirectional direction. The device to prevent electric shock and fire may also include: a detection / recovery device that is connected in parallel with a load or load side of the power line, detects an electrical fault in the power line, or detects the electrical fault in order to recover power. The sensing / recovery device may include: a second neutral point that is connected to the first neutral point; and two or more windings having one end connected to each of the two or more power lines, and the other end commonly connected to the second neutral point, each of the two or more windings may include at least a coupling winding portion magnetically coupled to any of the remaining windings, and at least one of the two or more windings may include the coupling winding portion in which voltages having phases opposite to those of the voltages applied to each of the remaining windings are induced with respect to the second neutral point. The power line can supply single-phase power, the sensing / recovery device can include first and second windings having one end connected to each of the power lines and the other end commonly connected to the second neutral point, and the first and second windings can be magnetically coupled to each other so that voltages having opposite phases to each other are each induced with respect to the second neutral point. The power line can supply three-phase power having phases T, R, S, the sensing / recovery device can include first to third windings having one end connected to each of the phases T, S, R and the other end commonly connected to the second neutral point, and each of the first to third winding can include the coupling winding portion in which the voltages having phases opposite to those of each of the voltages applied to the remaining windings are each induced with respect to the second neutral point. The power line can supply three-phase power having phases T, R, S, the sensing / recovery device can include first to third windings having one end connected to each of the phases T, R, S and the other end commonly connected to the second neutral point, and one of the first to third windings can include the coupling winding portion in which the voltages having phases opposite to those of each of the voltages applied to the remaining windings are each induced with respect to the second neutral point. In another general aspect, a method for preventing electric shock and fire includes: isolating two or more power lines from the earth with a resistance value greater than or equal to a predetermined earth resistance value; detecting a leakage current between at least one of the two or more power lines and a first neutral point having a potential between the voltages of the two or more power lines and the earth; and emitting a detection signal in accordance with the detection of the leakage current. The method for preventing an electric shock and fire may also include: cutting off a power supply to a power line through which the leakage current flows intertwined with the detection signal; and recovering the cut-off power and supplying the recovered power to a load. In yet another general aspect, a device for preventing electric shock and fire includes: a fault detector that is electrically connected to a power supply unit to transmit AC or DC electricity from the power supply unit to a load facility, and configured to detect if a leakage current occurs between at least one of two or more power lines isolated from earth with a resistance value greater than or equal to a predetermined earth resistance value and a neutral point having a potential between the voltages of the two or more power lines and earth, in which the fault detector operates to earth, for earth, a power line or neutral point at which the leakage current occurs between the two or more power lines and the neutral point when the leakage current occurs. The device to prevent electric shock and fire may also include: an earth switching unit that is controlled for short circuit, to earth, a power line or a neutral point at which leakage current occurs between the two or more power lines and the neutral point according to the detection result of the fault detector to ground the power line or neutral point. The fault detector may include two or more fault detectors respectively electrically connected between the two or more power lines and earth, and the ground switching unit may include two or more ground switches whose turning on or off is controlled in response to each of the two or more fault detectors. At least one of the two or more ground switches may be a normally open (NO) type switch that is turned on when an operating current greater than or equal to a predetermined reference value flows in a corresponding fault detector, and may be electrically connected to at least one of a power line and a neutral point other than a power line, to which the corresponding fault detector is connected, between the two or more power lines and the neutral point. At least one of the two or more ground switches may be a normally closed (NC) type switch that is turned off when an operating current greater than or equal to a predetermined reference value flows into the corresponding fault detector, and may be electrically connected in parallel to the corresponding fault detector. The power supply unit may be a three-phase AC power supply that includes one phase-R, one phase-S, and one phase-T; the fault detector may include first to third fault detectors respectively connected between phase-R, phase-S, and phase-T and earth; the earth switching unit may include first to third earth switches that correspond to each of the first to third fault detectors and are turned on when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector; and the first to third earth switches may be installed between a plurality of power lines and earth such that, when leakage current or earth fault occurs in any of the plurality of power lines connected to phase-R, phase-S, and phase-T, the corresponding power line is grounded. The power supply unit may be a three-phase AC power supply including one phase-R, one phase-S, and one phase-T. The fault detector may include first to third fault detectors respectively connected between phase-R, phase-S, and phase-T and earth. The earth switching unit may include first to third earth switches corresponding to each of the first to third fault detectors and are turned off when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector. The first to third earth switches may be installed between a plurality of power lines and earth so that when leakage current or earth fault occurs in one or more of the plurality of power lines connected to phase-R, phase-S, and phase-T, the corresponding power line is connected to earth. A distribution system for preventing electric shock and fire includes: a power supply unit configured to provide AC or DC electricity to a load facility; two or more power lines that are electrically connected to the power supply unit and insulated from earth with a resistance value greater than or equal to a predetermined earth resistance value; and the device for preventing electric shock and fire described above. In yet another general aspect, a device for preventing electric shock and fire from a photovoltaic power generation system includes: one or more fault detectors that are electrically connected to a solar panel in which one or more solar cell modules are arranged to transmit electricity generated from the solar panel to a charging installation, and are electrically connected between at least one or two power lines and a neutral point having a potential between voltages of the two or more power lines and earth to detect if a leakage current occurs between at least one of the two power lines isolated from earth with a resistance value greater than or equal to a predetermined earth resistance value and earth;and a ground switching unit that is controlled to short-circuit to earth a power line in which leakage current occurs between the two or more power lines according to the detection result of the fault detector to ground the power line. The two or more power lines may include first and second DC power lines that transmit DC electricity generated from the solar panel, and the fault detector may include first and second fault detectors that have one end electrically connected to the first and second DC power lines, respectively, and form a current path for a leakage current flowing into the ground to detect the leakage current from the current path. The grounding unit may include: a first ground switch that is controlled to ground the first DC power line to earth when leakage current flows in the first DC power line according to the fault detector detection result. The two or more power lines may include first and second DC power lines that transmit DC electricity generated from the solar panel. The fault detector may include first and second fault detectors that are electrically connected between the first and second DC power lines and earth, respectively. In the first and second fault detectors, the operating current may flow at a predetermined reference value or higher in a normal state. When leakage current occurs, the operating current may flow to the fault detector connected to a DC power line, through which the leakage current flows, at a predetermined value or lower. The two or more power lines may include first and second DC power lines that transmit DC electricity generated from the solar panel. The fault detector may be electrically connected between a neutral point having a potential between the voltages of the two or more power lines and earth, and form a current path for a leakage current flowing into the earth to detect the leakage current from the current path. A power line in which the leakage current occurs may be identified from among the two or more power lines according to the direction of the leakage current flowing through the fault detector. In yet another general aspect, a photovoltaic power generation system including the device for preventing electric shock and fire includes: a solar panel in which one or more solar cell modules are arranged; two or more power lines that are electrically connected to the solar panel to transmit electricity generated from the solar panel to a load installation and insulated from the earth with a resistance value greater than or equal to a predetermined earth resistance value; and the device for preventing electric shock and fire described above. Advantageous effects According to a device, method, and distribution system for preventing electric shock and fire during current leakage and earth fault according to the present invention, by detecting a leakage current between a power line, which is insulated from the earth and supplies power, and the earth, to limit the detected leakage current to be a dangerous or lesser current or to cut off the leakage current flowing into a human body or peripheral installations, it is possible to prevent electric shock and the occurrence of fire due to leakage current. Furthermore, according to the present invention, by detecting a leakage current between a power line, which transmits AC or DC electricity, and the earth, and grounding the power line through which the leakage current flows to the earth when the leakage current occurs, it is possible to fundamentally prevent a human body from receiving an electric shock from the leakage current flowing in the human body. Furthermore, according to the present invention, by detecting a leakage current caused by a ground fault or current leakage occurring in one or more lines and fundamentally preventing the leakage current from flowing outside, it is possible to prevent the occurrence of fire due to the ground fault or current leakage. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 is a block diagram illustrating the overall configuration of a device for preventing electric shock and fire during current leakage and earth fault according to the present invention. Figs. 2A, 2B and 2C are a block diagram illustrating an internal block of a fault detector according to the present invention. Fig. 3 is a conceptual diagram illustrating a principle of a device for preventing electric shock and fire according to a first embodiment of the present invention for detecting a leakage current. Fig. 4 is a conceptual diagram illustrating a principle of a device for preventing electric shock and fire according to a second embodiment of the present invention for detecting a leakage current. Figs. 5A and 5B are a diagram illustrating a configuration and a vector diagram of a detection / recovery device of the present invention applicable to a single-phase power supply. Figs. 6A and 6B are a diagram illustrating an exemplary configuration and vector diagram of a detection / recovery device applicable to a three-phase power supply. Figs. 7A and 7B are a diagram illustrating another exemplary configuration and vector diagram of the detection / recovery device applicable to three-phase power supply. Fig. 8 is a circuit diagram of the device for preventing electric shock and fire according to the present invention, to which the fault detector and the detection / recovery device are applied simultaneously. Fig. 9 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to the single-phase power supply Fig. 10 is a connection diagram in which the device for preventing electric shock and fire according to the present invention, including the detection / recovery device, is applied to the single-phase power supply. Fig. 11 is another connection diagram in which the device for preventing electric shock and fire according to the present invention, including the detection / recovery device, is applied to the single-phase power supply. Fig. 12 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to the three-phase power supply. Fig. 13 is a connection diagram in which the device for preventing electric shock and fire according to the present invention, including the detection / recovery device, is applied to the three-phase power supply. Fig. 14 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to a branch of the single-phase power supply. Fig. 15 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to a power line of the three-phase power supply. Fig. 16 is a connection diagram in which the device for preventing electric shock and fire according to the present invention, including the detection / recovery device, is applied to the branch of the three-phase power supply. Fig. 17 is a connection diagram illustrating a configuration of a device to prevent electric shock and fire during current leakage and earth fault according to a third embodiment of the present invention and a distribution system including the same. Fig. 18 is a conceptual diagram to describe an operation in a normal state in the third embodiment of the present invention illustrated in Fig. 17. Figs. 19A, 19B, 20A and 20B are conceptual diagrams to describe an operation when a current leakage or ground fault occurs in one phase in the third modality of the present invention. Figs. 21A and 21B are a conceptual diagram to describe an operation when current leakage or ground fault occurs in two phases in the third modality of the present invention. Fig. 22 is a connection diagram illustrating the configuration of a device to prevent electric shock and fire during current leakage and earth fault according to a fourth embodiment of the present invention and a distribution system including the same. Fig. 23 is a conceptual diagram to describe an operation when current leakage or ground fault occurs in one phase in the fourth modality of the present invention illustrated in Fig. 22. Fig. 24 is a connection diagram when the configuration according to the third modality of the present invention is applied to the three-phase power supply. Fig. 25 is a connection diagram when the configuration according to the fourth modality of the present invention is applied to the three-phase power supply. Fig. 26 is a block diagram illustrating the overall configuration of a photovoltaic power generation system including the device to prevent electric shock and fire during current leakage or ground fault according to the present invention. Fig. 27 is a connection diagram illustrating an example in which a fault detector is connected to a power line according to a fifth embodiment of the present invention. Figs. 28A and 28B are a connection diagram illustrating an example in which a fault detector is connected to a neutral point according to a sixth embodiment of the present invention. Figs. 29A and 29B are a connection diagram that illustrates another example in which the fault detector is connected to the neutral point according to the sixth modality of the present invention. Figs. 30A and 30B are a conceptual diagram illustrating the fault detector principle that detects leakage current and grounds the power line to earth in the manner illustrated in Figs. 29A and 29B. DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following detailed description is merely an example and illustrates only exemplary embodiments of the present invention. According to the present invention, a device can be applied to prevent electric shock and fire during current leakage and ground faults in electrical installations and their loads installed in offices or outdoors to prevent electrical accidents such as electric shock or fire caused by a leakage current. Herein, electrical installations include all installations that use electricity, such as a power receiving / distribution installation, a transformer, various control panels including a motor control panel, a temporary distribution board, a street lighting distribution board, a cable reel, and direct current installations such as solar lighting and ESS, in addition to the power receiving / distribution panel. The load includes electrical equipment, appliances, disaster prevention equipment, and environmental equipment that uses electricity. The device for preventing electric shock and fire of the present invention can be applied to electrical installations handling not only AC but also DC electricity, and in the case of AC, it can be applied to a polyphase power supply, including a multiphase power supply, as well as a single-phase power supply in the case of AC. When a leakage current occurs in electrical installations and loads due to flooding caused by natural disasters, age or damage, current leakage, or a ground fault, the device for preventing electric shock and fire of the present invention can prevent electric shock and fire due to the leakage current by limiting the leakage current flowing into the ground to a dangerous or lower level and by detecting the leakage current. Fig. 1 is a flow diagram illustrating the overall configuration of a device for preventing electric shock and fire during electrical and ground faults according to the present invention. Referring to Fig. 1, according to the present invention, a device for preventing electric shock and fire during current leakage and earth fault includes one or more fault detectors 210 electrically connected between at least one or two or more earth-insulated power lines PL2 with a resistance value greater than or equal to a predetermined earth resistance value and a first neutral point N1 having a potential between the voltages of the two or more power lines PL2 and earth. In this case, the fault detector 210 is configured to form a current path for a leakage current flowing from two or more power lines PL2 or the first neutral point N1 to earth due to the flooding of at least one of the two or more power lines, causing current leakage, earth fault, human contact, etc.In addition, the fault detector 210 can be controlled to detect a leakage current flowing between the power line PL2 or the first neutral point N1 and earth and emit a detection signal and cut off the power supply to the power line PL2 through which a leakage current flows, intertwining with the detection signal. The PL2 power line is a conductor that supplies power to one side of a 290 load or an electrical receiving installation, including a power receiving / distribution installation around the 290 load. It is a collective term for all conductors that are electrically connected to each other and carry power on the same phase. This includes not only separate conductors, separated by a 270 circuit breaker or switch, but also a branch line that connects through the 270 circuit breaker, switch, equipment, etc., or branches off from a main line. In this case, it is preferable that the PL2 power line be insulated from earth to have a resistance value greater than or equal to a predetermined earth resistance.Here, isolation is not limited to the case of complete isolation, and includes the case where the power line PL2 or neutral point has a resistance value greater than a normal ground resistance with the earth through the grounding connection. A power supply connected to the PL2 power line can be either DC or AC. When the power supply is DC, it can be solar or an energy storage system (ESS). When the power supply is AC, it can be single-phase, three-phase, or polyphase, where the voltages of each phase have a predetermined phase difference. For the sake of clarity, the single-phase AC method will be described primarily hereafter, and three-phase AC and DC power supplies will be described further if necessary. The first neutral point N1 refers to a conduction point that has a potential between the potentials of two or more power lines PL2, and can be drawn from a transformer's center tap or formed by summing the voltages of the power lines PL2 at a predetermined ratio. It is sufficient that the sum of the voltages of the power lines PL2 with respect to the first neutral point N1 be 0, and therefore, the magnitudes of the voltages of the power lines PL2 with respect to the first neutral point N1 are not necessarily the same. However, a description will be made under the assumption that the phase voltages of the power lines PL2 are out of phase with each other but have the same magnitude. Fault detector 210 is electrically connected between at least one of the two or more power lines PL2 and the first neutral point N1 and earth to form a current path for a leakage current flowing from the two or more power lines PL2 or the first neutral point N1 to earth. In this case, fault detector 210 can be controlled to detect the leakage current and output the signal. 1. Detection, or cutting off the power supply to the PL2 power line or the neutral point through which the leakage current flows, intertwining with the detection signal. Here, the electrical connection includes not only a direct connection, but also an indirect connection through other electrical elements. The fault detector 210 of the present invention can be installed on the power line PL2 or only on the first neutral point N1, or it can be installed on both the power line PL2 and the first neutral point N1. Furthermore, even when the fault detector 210 is installed only on the power line PL2, it can be configured to be installed not only on all power lines PL2 but also on some of them. Preferably, the fault detector 210 can be installed on all power lines PL2 to detect all leakage currents from the power lines PL2 to earth, and furthermore, to specify the power lines PL2 where the leakage current occurred. The device for preventing electric shock and fire according to the present invention is directed to the power line PL2, which is isolated from earth with a predetermined or greater resistance value. However, even if the power receiving / distribution line PL1 in Fig. 1 is not isolated from earth, or is isolated, if necessary, for the purpose of isolating the power receiving / distribution line PL1, the device for preventing electric shock and fire of the present invention may further include an isolation transformer 240 between the power receiving / distribution line PL1 and the power line PL2 on which the fault detector 210 is installed. The isolation transformer 240 includes a primary side to which the power receiving / distribution line PL1 is connected and a secondary side isolated from the primary side. The secondary side can be electrically connected to two or more power lines PL2. Therefore, power line PL2 and the first neutral point N1 are isolated from earth so that fault detector 210 can be installed. The first neutral point N1 can be taken from a center tap on the secondary winding of the isolation transformer 240, but this can be omitted if fault detector 210 is to be installed only on power line PL2. Furthermore, the isolation transformer 240 can be a single-phase or three-phase transformer, but it is not limited to either and can be a polyphase transformer wound for polyphase output. Furthermore, the device for preventing electric shock and fire according to the present invention can be configured to include an open / close switch 213 and a circuit breaker 270 that are installed in series on the power line PL2 and controlled to cut off the power by opening and closing the power line PL2 interleaved with the detection signal from the fault detector 210. Here, opening / closing the power line PL2 interleaved with the detection signal means that the open / close switch 213 and the circuit breaker 270 are directly controlled by the detection signal from the fault detector 210, and opening / closing is controlled by external control means receiving the detection signal. The 213 on / off switch and the 270 circuit breaker have the same function in terms of interrupting power, but the 270 circuit breaker has a configuration primarily used in power receiving / distribution installations, and includes a leakage current circuit breaker, a wiring circuit breaker, MG / SW, an electromagnetic switch, ACB, VCB, AISS, LBS, etc. Alternatively, the 213 on / off switch can be a non-standard switching device. In particular, the 270 circuit breaker can open and close lines simultaneously, while the 213 on / off switch can be configured to open and close only lines individually where an electrical fault occurs.Therefore, in the device for preventing electric shock and fire according to the present invention, the fault detector 210 can be installed so as to specify the power line PL2 through which the leakage current flows due to the electrical fault such as ground fault, current leakage, or electric shock, and the open / close switch 213 can be configured to selectively cut off the power line PL2 in which the electrical fault occurred. Also, as illustrated in Fig. 1, the open / close switch 213 is installed on the incoming and load sides 290 of power line PL2, respectively, to divide power line PL2 into a predetermined section. In this way, when leakage current occurs in a predetermined section, the cause can be eliminated by interrupting only the portion of power line PL2 where the leakage current has occurred. As will be described later, in this case, the recovered power can be supplied to load 290 without interruption using the uninterrupted power line PL2 and the neutral line NL. Furthermore, the device for preventing electric shock and fire according to the present invention can be configured to include a detection / recovery device 230 connected in parallel with the load 290 on the load side of the power line PL2. The detection / recovery device 230 can be configured to detect an electrical fault (leakage current, increased resistance, arcing, disconnection, phase loss, unbalanced power, poor connection, faulty connection, current leakage, short circuit, abnormal voltage) of the power line PL2, or to restore power to the corresponding power line PL2 when a power line PL2 is interrupted due to disconnection, phase loss, or leakage current, and to supply restored power to the load 290. The structure and function of the detection / recovery device 230 will be described in detail later. Figs. 2A, 2B and 2C are a block diagram illustrating an internal block of the fault detector 210 according to the present invention. Referring to Figs. 2A, 2B, and 2C, each fault detector 210 according to the present invention includes a current sensing unit 211 that limits a leakage current to a predetermined or lower hazardous current, detects the leakage current, and emits a detection signal. Furthermore, each fault detector 210 may also include a unidirectional current unit 212 that limits a path for the leakage current in a predetermined direction, such that the leakage current flows through the current sensing unit 211 in a unidirectional direction. The current detection unit 211 is a component for detecting leakage current flowing from the power line PL2 or the first neutral point N1 to earth. It can detect the leakage current and output a corresponding detection signal. The detection signal can include information about the magnitude and direction of the leakage current and can be emitted if the leakage current exceeds a preset threshold value. The detection signal is provided directly to the open / close switch 213 or circuit breaker 270 installed on the power line PL2, or a separately installed controller 220 controls the open / close switch 213 or circuit breaker 270 to be opened / closed. Alternatively, a control signal for alarm, fault location indication, or fault recovery can be provided to the controller 220 for output.In this case, controller 220 can either send an alarm signal via an alarm generator 250, or release an alarm when an administrator enters an alarm release command to an alarm release input device 260. In addition, the current detection unit 211 may also include a current limiting means (not illustrated) arranged in series in a current path through which the leakage current flows, such that the leakage current becomes less than or equal to a predetermined hazardous current. In this case, the current limiting means may be configured to have a voltage-drop device, including a resistive device, to limit a current value to a hazardous current or less with respect to a voltage applied to a fault detection unit when the leakage current occurs. Here, the dangerous current is a current that may cause electric shock to the human body or fire, and may be appropriately established according to the purpose of use of the electrical installation 100. For reference, because it has been known that when the leakage current flowing in the human body is 15 mA or more, it causes convulsions (pain) and when the leakage current is 50 mA or more, it causes death, in order to avoid accidents of electric shock, the dangerous current may be established at 15 mA or less, for example, 8 mA, so that the leakage current may be designed to be limited to the current value or less. Furthermore, the 211 current detection unit can be configured to detect leakage current at any point along a current path through which the leakage current flows. For example, leakage current can be detected using a voltage applied to the current-limiting means or by using a current sensor installed at any point along the current path. The current sensor can be configured to include either a Hall effect sensor or a current transformer (CT). The fault detector 210 according to the present invention can be configured to further include a switch for controlling opening and closing by interleaving it with the detection signal. In this case, the switch can operate as the open / close switch 213 described above and can be provided integrally with the fault detector 210 along with the current sensing unit 211. In this case, the integrated switch and current sensing unit 211 can be implemented as a solid-state relay (SSR). The unidirectional current unit 212 is a component that restricts the path of leakage current in a predetermined direction, ensuring that the leakage current flows through the current-sensing unit 211 in only one direction. It can be configured to include a switching device or a diode that is controlled to conduct current only in a predetermined direction. Specifically, when the unidirectional current unit 212 is configured as the diode, it can be in the form of a rectifier circuit including one or more diodes (Fig. 2A), or it can be configured as a bridge diode circuit (Fig. 2B). The fault detector 210 configured to include the unidirectional current unit 212 can be installed on the power line PL2 in the case of AC power or installed at the first neutral point N1 in the case of DC power to identify the power line PL2 through which the leakage current flows. That is, fault detector 210, configured to include unidirectional current unit 212, can be installed on power line PL2 or at a neutral point N to identify the power line PL2 through which the leakage current flows, according to the direction of the leakage current. In this case, fault detector 210 can detect which of the two or more power lines PL2 the leakage current occurs on by using the unidirectional current unit 212, which is configured to detect leakage current flow in different directions. Furthermore, the fault detector 210 according to the present invention can be configured to detect the power line PL2 in which the leakage current occurred without using the unidirectional current unit 212. Referring to Fig. 2C, the current detection unit 211 can be configured to identify the direction of the leakage current flowing through the fault detector 210. For example, as illustrated in Fig. 2C, the current detection unit 211 can emit different types of detection signals, i.e., detection signals of different polarities, depending on the direction of the leakage current, and identify which power line is the power line PL2 through which the leakage current flows based on the detection signal. Fig. 3 is a conceptual diagram illustrating a principle of a device for preventing electric shock and fire according to a first embodiment of the present invention for detecting a leakage current. Referring to Fig. 3, the device for preventing electric shock and fire according to the present invention may be configured to include the fault detector 210 installed between the first neutral point N1, which has a potential between the power line voltages PL2 and earth. In order to isolate the power line PL2 from earth, the isolation transformer 240 may be installed between the power receiving / distribution line PL1 and the power line PL2, and the power line PL2 and the first neutral point N1 may be connected to the secondary side of the isolation transformer 240. When a ground fault or human contact occurs on any of the two or more PL2 power lines, and a leakage current flows, this current flows at the first neutral point N1 through fault detector 210, as illustrated in Fig. 3. In this case, fault detector 210 detects the leakage current while limiting it to a level that is harmless to the human body. Fig. 3 illustrates a case where leakage current occurs on one of the single-phase PL2 power lines, but even in the case of the remaining PL2 or three-phase power lines, fault detector 210 can detect leakage current in a similar manner. As illustrated in Fig. 3, the fault detector 210 connected to the first neutral point N1 for AC power does not require the unidirectional current unit 212 and detects the presence or absence of leakage current without considering the power line PL2 where the leakage current occurs. However, in the case of DC power, installing the fault detector 210, including the unidirectional current unit 212, at the first neutral point N1 makes it possible to identify and detect not only the occurrence of leakage current but also the power line PL2 where the leakage current occurred. In this case, the fault detector 210 is connected in parallel, and the current direction of each one-way current unit 212 of the fault detector 210 is set in a reverse direction, or it is possible to identify the power line PL2 in which the leakage current occurs using the fault detector 210 by including the one-way current unit 212 in the form of a bridge diode illustrated in Fig. 2B. Fig. 4 is a conceptual diagram illustrating a principle for detecting a leakage current by identifying the power line through which the leakage current flows using a device to prevent electric shock and fire according to a second embodiment of the present invention. Referring to Fig. 4, the device for preventing electric shock and fire according to the second embodiment of the present invention is configured to include first and second fault detectors 210-1 and 210-2 respectively connected between a power line having single-phase voltages R1 and R2 and ground. In this case, the first and second fault detectors 210-1 and 210-2 include a unidirectional current unit 212, and the current direction permitted by the unidirectional current unit 212 is established between the single-phase voltages R1 and R2 in a reverse direction to prevent current from flowing between the two ends of the single-phase voltages R1 and R2. According to Fig. 4, when leakage current 1 occurs in R1 of the power line, a current path through which leakage current 1 flows in the first fault detector 210-1 along the solid line illustrated in the figures is formed, and when leakage current 2 occurs in R2 of the power line, a current path through which leakage current 2 flows in the second fault detector 210-2 along a dashed line is formed. Therefore, the first fault detector 210-1 emits the detection signal to the power line in which leakage current 1 has occurred, and the second fault detector 210-2 emits the detection signal to the power line in which leakage current 2 has occurred, so that the device for preventing electric shock and fire of the present invention can identify and detect the power line in which the leakage current has occurred. The foregoing has described the case of single-phase AC as an example, but the detection principle is not limited to this and can be applied to a polyphase power supply, including three-phase or more power supplies. In other words, the fault detector of the present invention can be electrically connected between each of the two or more power lines and earth, and can be configured so that the leakage current flowing in any of the two or more power lines is detected by the fault detector connected to the remaining power lines between the fault detectors. By means of the configuration described above, the electric shock and fire prevention device of the present invention can identify and disconnect the power line through which the leakage current is flowing to prevent injury and fire. Furthermore, the electric shock and fire prevention device of the present invention selectively disconnects only the power line in which the leakage current is occurring, so that the detection / recovery device 230 of the present invention can use the unblocked power line and the first neutral point N1 to restore the disconnected power and supply the restored power to the load 290. In general, the detection / recovery device 230 of the present invention may be configured to include a second neutral point N2 that connects to the first neutral point N1, and two or more windings having one end connected to each of the two or more power lines and the other end commonly connected to the second neutral point N2. In this case, each of the two or more windings includes at least a coupling winding portion magnetically coupled to any of the remaining windings, and at least one coil of the two or more coils is configured to include a coupling winding portion in which voltages having phases opposite to those of the voltages applied to each of the remaining windings are induced with respect to the second neutral point N2, respectively. Figs. 5A and 5B are a diagram illustrating a configuration and a vector diagram of the sensing / recovery device 230 of the present invention applicable to single-phase power supply. Referring to Fig. 5A, the sensing / recovery device 230 applied to a single-phase voltage can be configured to include first and second windings R1-N2 and R2-N2, each with one end connected to one of the single-phase voltages and the other end commonly connected to the second neutral point N2. In this case, as illustrated in Fig. 5B, the first and second windings R1-N2 and R2-N2 are magnetically coupled to each other so that the voltages having opposite phases are induced with respect to the second neutral point N2. Therefore, when a leakage current occurs on the R1 or R2 side of the single-phase voltage, and the corresponding line (e.g., R2) is forcibly interrupted, a normal voltage can be supplied to the load 290 by restoring the interrupted portion using the remaining normal lines (e.g., R1) and the second neutral point N2. The single-phase detection / recovery device 230 of the present invention has a simple winding transformer structure type, but is not limited to the case in which the winding ratio of the first winding R1-N2:the second winding R2-N2 is limited to: 1:1, but can be established in various ways and manufactured if necessary. However, when the detection / recovery device 230 and the isolation transformer 240 are electrically connected through the power line, it is preferable to establish the winding ratio of the detection / recovery device 230 in accordance with the winding ratio of the corresponding isolation transformer 240. The detection / recovery device 230 of the present invention can also be applied to a three-phase power supply. Figs. 6A and 6B are a diagram illustrating an exemplary configuration and vector diagram of the 230 detection / recovery device applicable to three-phase power supply. Referring to Fig. 6A, the detection / recovery device 230 of the present invention applicable to three-phase power supply includes first to third windings 231, 232, and 233 having one end connected to each of the phases R, S, and T for three-phase powers having phases R, S, and T, and the other end commonly connected to the second neutral point N2, and each of the first to third windings 231, 232, and 233 can be configured to include the coupling winding portion in which voltages having phases opposite to those of the voltages applied to the remaining windings are induced with respect to the second neutral point N2, respectively. According to the configuration in Fig. 6A, three coupling winding portions are provided in the first winding 231 connected to phase R, and voltages with vectors Rr, Rs, and Rt are induced in each coupling winding portion. Additionally, three coupling winding portions are provided in the second winding 232 connected to phase S, and voltages with vectors Ss, St, and Sr are induced in each coupling winding portion. Furthermore, three coupling winding portions are provided in the third winding 233 connected to phase T, and voltages with vectors Tt, Tr, and Ts are induced in each coupling winding portion. In three-phase power supply, the sum of the vectors R, S and T, respectively, is 0, so the relationship between the voltages that have the phase R, S and T is expressed by means of Equation 1. Equation 1 R+S+T=O When a three-phase voltage is applied to the first to third windings 231, 232, and 233, respectively, because the voltage induced in the first to third windings 231, 232, and 233 with respect to the second neutral point N2 is equal to the sum of the voltages induced in the coupling winding portions provided in each winding, it is expressed as a vector expression as shown in Equations 2 to 4. Equation 2 R=Rr+Rs+Rt Equation 3 S=Ss+St+Sr Equation 4 T=Tt+Tr+Ts In order to aid in the understanding of Equations 1 to 4 above, the induced voltage vector diagram is illustrated in Fig. 6B. Referring to Fig. 6B, each winding is configured to include the coupling winding portion in which voltages opposite in phase to those applied to each of the remaining windings are induced with respect to the second neutral point N2, respectively. In other words, in the case of the first winding 231, the coupling winding portion that induces the voltages of vectors Rs and Rt induces voltages opposite in phase to those of phase-S and phase-T, respectively. In the case of the second winding 232, the voltages of vectors Sr and St are opposite in phase to those of phase-R and phase-T, respectively. Furthermore, in the case of the third winding 233, the voltages of vectors Tr and Ts are opposite in phase to those of phase-R and phase-S, respectively. Furthermore, the coupling winding portion that induces the voltage vector Rr between the coupling winding portions of the first winding 231 induces voltages that have opposite phases to those of the coupling winding portion Tr and the coupling winding portion Sr. Similarly, the vector Ss in the second winding 232 has opposite phases to Rs and Ts, and the vector Tt in the third winding 233 has opposite phases to vectors St and Rt. If the relationship between the induced voltages in the coupling winding portion is arranged in a vector expression, it is as shown in Equations 5 to 7 below. Equation 5 Rr=-Sr=-Tr Equation 6 Ss=-Ts=-Rs Equation 7 Tt=-Rt=-St Even if any of the R, S, and T phases applied to the first to third windings 231, 232, and 233 is lost due to disconnection or other electrical faults, the detection / recovery device 230 of the present invention, which is configured to satisfy the above conditions, can recover a lost phase voltage from the remaining phases and supply the recovered voltage to the load 290. While the three-phase R, S, and T power line is operating, connecting the first to the third windings 231, 232, and 233 of the sensing / recovery device 230, it is assumed that any other phase (e.g., phase-R) is disconnected / lost due to a critical fault. In this case, because phases S and T are generally applied to the second winding 232 and the third winding 233, which are not disconnected, the relational expressions in Equations 3 through 7 hold. However, because phase-R is not applied to the first winding 231, it can be seen that Equation 2 is not valid, and an unknown voltage X, defined in Equation 8, is induced in the first winding 231. Equation 8 X=Rr+Rs+R1 From here on, it will be mathematically examined whether the unknown voltage X induced in the first winding 231 that has the lost phase restores the lost phase-R. By rearranging S and T expressed in Equations 3 and 4 with respect to Rr, Rs, and Rt using Equations 5 to 7, Equation 9 below can be obtained. Equation 9 Furthermore, when all coupling winding portions of the sensing / recovery device 230 have the same winding ratio, the magnitudes of induced voltages in each coupling winding portion are equal to each other as shown in Equation 10 below. Equation 10 |^r| = |^| = |J? / | = |S>| = ^ Equation 11 can be obtained by obtaining Rs+Rt using Equation 10 and Equations 3 to 7 above. Equation 11 Rs । / ? / —y (S+T) By substituting Equations 9 to 11 into Equation 8 and rearranging these Equations 9 to 11 using Equation 1, the unknown voltage X induced in the first winding 231 whose phase-R was lost is obtained by means of Equation 12. Equation 12 X=Rr+Rs+Rt=-^ (S+T)-^· (S+T)=-{S+T)=R It can be seen from Equation 12 that, even if the phase-R to be applied to the first winding 231 is lost, the detection / recovery device 230 of the present invention uses the phases S and T applied to the second and third windings 232 and 233 to recover the voltage that the phase-R has in the first winding 231. In the above, the case where phase-R is lost in the first winding 231 of the sensing / recovery device 230 is described as an example, but energy can be recovered in the same way even when phase loss occurs in phase-S or phase-T applied to the second and third windings 232 and 233. Figures 6A and 6B illustrate a structure in which the first to third windings 231, 232, and 233 of the sensing / recovery device 230 each include three coupling winding portions, but the sensing / recovery device 230 of the present invention is not limited to that, and can be changed in various ways as long as at least one of the first to third windings 231, 232, and 233 has a structure that includes a coupling winding portion in which voltages having phases opposite to those of each voltage applied to the remaining windings are induced, respectively. For example, although not illustrated in the figure, the detection / recovery device 230 of the present invention may have a structure in which the coupling winding portions corresponding to Rs, Ss, and Tt provided in the first to third windings 231, 232, and 233 are omitted from the configuration of Figs. 6A and 6B. Using a test process similar to Equations 1 to 12, it can be seen that the voltage is normally restored to a lost-phase winding in this structure as well. Also, the detection / recovery device 230 of the present invention can be configured to have a simpler structure for the supply of three-phase power. Figs. 7A and 7B are a diagram illustrating another exemplary configuration and vector diagram of the 230 detection / recovery device applicable to three-phase power supply. Referring to Figs. 7A and 7B, the sensing / recovery device 230 of the present invention includes the first to third windings 231, 232, and 233 having one end connected to each of the phases R, S, and T, and the other end commonly connected to the second neutral point N2, and one of the first to third windings 231, 232, and 233 can be configured to include the coupling winding portion in which the phase voltages opposite to those of the voltages applied to the remaining windings are induced with respect to the second neutral point N2, respectively. The sensing / recovery device 230 of Fig. 7A includes the coupling winding in which the vector voltages Rs and Rt are induced in the first winding 231 to which phase-R is applied, and Rs and Rt have voltages having opposite phases to phases S and T of the second and third windings 232 and 233, respectively. Fig.7B Illustrate a vector diagram that shows this relationship. As the principle of the detection / recovery device 230 having the structure of Fig. 6A to recover the lost phase was previously demonstrated mathematically, the principle of lost phase recovery can be examined through a similar process for the structure of Fig. 7A. In three-phase power supply, the sum of the vectors R, S and T, respectively, is 0, so when the relationship between the phase voltages R, S and T is expressed as in Equation 1, Equation 13, identical to Equation 1, can be obtained. Equation 13 R+S+T=O The applied or induced voltages in the first to third windings 231, 232 and 233 with respect to the second neutral point N2 are expressed as the vector expression as shown in Equations 14 to 16 below. Equation 14 R=Rs+Rt Equation 15 S=Ss Equation 16 T=Tt In order to aid in the understanding of Equations 14 to 16 above, the induced voltage vector diagram is illustrated in Fig. 7B. Referring to Fig. 7B, it can be seen that the coupling winding portion in which the Rs and Rt vector voltages are induced in the first winding 231 induces voltages that have opposite phases to phase-S and phase-T, respectively. Furthermore, between the coupling winding portions of the first winding 231, the coupling winding portion in which the vector voltage Rs is induced induces a voltage that has an opposite phase to that of the coupling winding portion Ss, and the coupling winding portion in which the vector voltage Rt is induced induces a voltage that has an opposite phase to that of the coupling winding portion Tt. As described above, if the relationship between the induced voltages in the coupling winding portion is arranged in the vector expression, this is as shown in the following Equations 17 and 18. Equation 17 Rs=-Ss Equation 8 Rt=-Tt Even if any of the applied phases R, S, and T from the first to third windings 231, 232, and 233 is lost due to disconnection or other electrical faults, the detection / recovery device 230 of the present invention, which is configured to satisfy the above conditions, can recover a lost phase voltage from the remaining phases and supply the recovered voltage to the load 290. Although the three-phase R, S, and T power line operates by connecting the first through third windings 231, 232, and 233 of the sensing / recovery device 230, it is assumed that any phase (e.g., phase-R) is disconnected / lost due to the electrical fault. In this case, because phases S and T are generally applied to the second winding 232 and the third winding 233, which are not disconnected, the relational expressions in Equations 15 through 18 are established. However, because phase R is lost in the first winding 231, it can be seen that Equation 14 is not valid, and an unknown voltage X, defined in Equation 19, is induced in the first winding 231. Equation 19 Xr=Rs+Rt Substituting Equations 17 and 18 into Equation 19 and rearranging these Equations 17 and 18 using Equation 13, the unknown voltage Xr induced in the first winding 231 whose phase-R was lost was obtained using Equation 20. Equation 20 Xr =Rs +Rt=- (Ss+Tt) =- (S+T) =R Similarly, the case in which the S-phase or T-phase is lost in the second winding 232 or the third winding 233 is also obtained by the following Equations 21 and 22. Equation 21 Xs=Ss =- (R+Tt) =- (R+T) =S Equation 22 Xt=Tt=-(R±Ss)=-(R+S) = T It can be seen from Equations 20 to 22 that even if phase loss or disconnection occurs in any of the first to third windings 231, 232, and 233, as illustrated in the vector diagram of Fig. 7B, the sensing / recovery device 230, having the structure illustrated in Fig. 7A, recovers the phase loss voltage using the voltage applied to the remaining windings. In particular, the sensing / recovery device 230, having the structure illustrated in Figs. 7A and 7B, can include only two magnetic cores instead of three for magnetic coupling, and thus, there is an advantage in that the winding structure can be simplified to reduce the process and cost during production. The detection / recovery device 230 of the present invention is not limited to the structure described above, and can be changed in various ways as long as at least one of the first to third windings 231, 232, and 233 has a structure that includes a coupling winding portion in which voltages having phases opposite to those of each voltage applied to the remaining windings are induced, respectively. Fig. 8 is a connection diagram of the device for preventing electric shock and fire according to the present invention to which the fault detector 210 and the detection / recovery device 230 are applied at the same time. Referring to Fig. 8, a device for preventing electric shock and fire according to the present invention can be configured to include the detection / recovery device 230 that is electrically connected to the load side 290 of the first neutral point N1 and the single-phase voltages R1 and R2, the first and second fault detectors 210-1 and 210-2 respectively connected between phase R2 and phase R1 of the single-phase voltages R1 and R2 and earth, and first and second open / close switches 213-1 and 213-2 provided on the power supply side and the load side 290 of the single-phase voltages R1 and R2 to divide the power line into predetermined sections.Therefore, in the normal operating state in which electrical faults such as leakage current do not occur, an AC voltage via the single-phase voltages R1 and R2 is applied to load 290 and the detection / recovery device 230, so that load 290 can operate normally. However, as illustrated in Fig. 8, when leakage current occurs in the line at R2, which is divided by the second open / close switch 213-2, the leakage current is detected by the second fault detector 210-2 connected to R1, and a detection signal is emitted. Furthermore, the second open / close switch 213-2 interleaves with the detection signal from the second output fault detector 210-2, and thus, the second open / close switch 213-2 blocks the predetermined divided section of the phase line R2. Even if phase R2 is interrupted due to leakage current, 1 / 2 Vac is applied to terminal R1 and the second neutral point N2 of the detection / recovery device 230 by the uninterrupted phase R1 and the first neutral point N1, and 1 / 2 Vac is restored between terminal R2 and the second neutral point N2 of the detection / recovery device 230 according to the recovery principle described above. Therefore, even if phase R2 is interrupted by leakage current, the load 290 can be continuously supplied with Vac by the detection / recovery device 230 and operates normally. Fig. 8 shows a case where leakage current occurs in the line at R2, but even when leakage current occurs at R1, the device for preventing electric shock and fire of the present invention can perform similar detection, cutting, and recovery operations. From this point forward, the ways in which the device for preventing electric shock and fire of the present invention is applied to electrical installation 100 are presented as exemplary connection diagrams. The following detailed description and connection diagrams are merely exemplary and may be modified and applied in many different ways, which is solely within the scope of the creative ability of a person skilled in the art. Fig. 9 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to the single-phase power supply. Referring to Fig. 9, the device for preventing electric shock and fire according to the present invention may include the isolation transformer 240 for isolating the power line PL2 and the first neutral point N1 from the power receiving / distribution line PL1 taken from a grounded main transformer 300 with a resistance value greater than or equal to the ground resistance value, and the first fault detection device 210-1 provided between the first neutral point N1 and ground. Alternatively or additionally, the second fault detection device 210-2 may also be installed between the power line PL2 and ground. Furthermore, in order to protect the electrical installation 100 from overvoltage, a surge protector 280 may be installed between at least one of the power line PL2 and the first neutral point N1 and earth. The power line PL2 and the first neutral point N1 to which the device is applied to prevent electric shock and fire according to the present invention are configured to have a resistance value greater than or equal to that of earth and earth resistance, and therefore, the power line PL2 and the first neutral point N1 may be vulnerable to overvoltage such as lightning, so that the surge protector 280 can supplement the overvoltage. Furthermore, the device for preventing electric shock and fire according to the present invention receives the detection signal from fault detectors 210-1 and 210-2, although not illustrated in Fig. 9, to determine whether a fault exists, and may further include controller 220, which emits a control signal in response to the determination. In this case, the control signal may include at least one of the following: a cut-off signal to cut off power to a leakage current, an alarm signal to sound an alarm that an electrical fault has occurred, a location signal to deploy a fault section or location, and a recovery signal to recover from a fault. Therefore, the circuit breaker 270, the open / close switch 213, etc., which are illustrated in the power line PL2, can be controlled to cut off the power supply by means of the detection signals from the fault detectors 201-1 and 210-2 or the control signal from the controller 220 which has received the detection signals when leakage current occurs. Fig. 10 is a connection diagram in which a device for preventing electric shock and fire is applied according to the present invention, including the detection / recovery device 230 to the single-phase power supply. The device for preventing electric shock and fire of the present invention, illustrated in Fig. 10, further includes the detection / recovery device 230 in the configuration of Fig. 9. The detection / recovery device 230, connected in parallel to the load side 290 of the power line PL2, can operate to detect electrical faults (leakage current, resistance increase, arcing, disconnection, phase loss, unbalanced power, poor connection, disconnection, current leakage, short circuit, occurrence of abnormal voltage) in the power line PL2, or restore power from the corresponding power line PL2 when a power line PL2 is interrupted due to disconnection, phase loss, or leakage current, and restore power from the corresponding power line PL2 to supply the restored power to the load 290. Fig. 11 is another connection diagram in which a device for preventing electric shock and fire according to the present invention, including the detection / recovery device 230, is applied to the single-phase power supply. Referring to Fig. 11, the device for preventing electric shock and fire of the present invention may include the isolation transformer 240 for electrically isolating the power receiving / distribution line PL1 and the power line PL2. Here, the power receiving / distribution line PL1 may be a line connected to earth, but also includes a line already isolated from earth by means of the isolation transformer 240. Furthermore, the device for preventing electric shock and fire of the present invention can be configured to include the open / close switches 213-1 and 213-2, each capable of opening and closing the power line PL2. Because the interlocking relationship between the open / close switches 213-1 and 213-2 and the fault detectors 210-1 to 210-4 is the same as described above, a detailed description thereof is omitted. Additionally, the fault detectors 210-1 to 210-4 can be electrically connected to at least one of the power line PL2 and the first neutral point N1, with the second neutral point N2 connected to the first neutral point N1 via the ground line NL. If necessary, a plurality of fault detectors 210-1 to 210-4 can be installed in parallel on the same line. The devices for preventing electric shock and fire according to the present invention can be applied to three-phase as well as single-phase power supplies. Figure 12 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to a three-phase power supply. Referring to Fig. 12, the main transformer 300, which receives power from an ultra-high voltage line, can connect the first fault detector 210-1 between the first neutral point N1 and ground without directly grounding the first neutral point N1 to ground. In this way, the main transformer 300 operates as an isolation transformer 240, whose secondary side is isolated from ground. Alternatively, or additionally, the second fault detector 210-2 can also be installed on at least one of the three-phase power lines PL2 on the secondary side of the main transformer 300. Furthermore, to protect the electrical installation 100 from overvoltage, a surge protector 280 can be installed on at least one of the power lines PL2, the first neutral point N1, and ground. Fig. 13 is a connection diagram in which a device for preventing electric shock and fire according to the present invention, including the detection / recovery device 230, is applied to the three-phase power supply. The device for preventing electric shock and fire of the present invention illustrated in Fig. 13 may further include the detection / recovery device 230 connected in parallel to the load side 290 in the three-phase connection diagram of Fig. 12.Here, in order to apply to three-phase power, the detection / recovery device 230 is configured for three-phase, and the detection / recovery device 230 can operate to detect electrical faults (leakage current, increased resistance, arcing, disconnection, phase loss, unbalanced power, poor connection, disconnection, leakage current, short circuit, abnormal voltage occurrence) of the power line PL2, or restore power from the cut power line PL2 using the remaining power line PL2 when a power line PL2 is cut due to disconnection, phase loss or leakage current of the power line PL2 and supply the restored power to the load 290. The device for preventing electric shock and fire according to the present invention can be applied not only to a main line of a receiving distribution line but also to a branch line. Figure 14 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to the single-phase power supply branch. Referring to Fig. 14, the device can be configured to prevent electric shock and fire according to the present invention by including the isolation transformer 240 to isolate the provided branch from the main line's ground. The isolation transformer 240 can be installed on all branches, but it is also possible to install it selectively only on branches with a high risk of electrical accidents due to leakage current.As illustrated in Fig. 14, when each branch includes the isolation transformer 240 and each fault detector 210 is installed on the secondary side of the isolation transformer 240, the fault detector 210 installed on the branch where the leakage current occurs detects the leakage current and transmits the detection signal to the controller 220 or directly controls the circuit breaker 270 or the open / close switch 213 to isolate the branch. In this case, the controller 220, which receives the detection signal, can identify the branch where the leakage current occurred and either issues an isolation signal (trip signal) to selectively isolate the branch or issues a location signal indicating the branch's location.Therefore, when the isolation transformer 240 and fault detector 210 are installed on each branch, there is an advantage in that it is possible to identify the location of the branch where the electrical fault occurs due to leakage current and selectively cut off only the branch. On the other hand, when the isolation transformer 240 and fault detector 210 are installed on the main line, there is no need to install the isolation transformer 240 and fault detector 210 for each branch, thus simplifying the connection. However, additional consideration may be required to selectively identify and isolate the branch where the leakage current occurred. For example, when leakage current occurs in any of the plurality of branch circuits from the main line, fault detector 210 transmits the detection signal to controller 220. Controller 220 can then identify the branch where the leakage current occurred while controlling the opening and closing of circuit breaker 270 to sequentially open the branch circuit breaker 270. In addition, although not illustrated in Fig. 14, the detection / recovery device 230 and the open / close switch 213 may be provided on the load side 290 of the power line PL2 so that each branch recovers the phase power supply lost during disconnection due to leakage current or electrical fault and stably supplies power to the load 290. Fig. 15 is a connection diagram in which the device for preventing electric shock and fire according to the present invention is applied to the branch of the three-phase power supply. The device for preventing electric shock and fire of the present invention, applied to the three-phase power supply branch illustrated in Fig. 15, has the same operating principle and connection method as the single-phase power supply of Fig. 14, except that the isolation transformer 240 is not provided on each branch. However, the main transformer 300 provided on the main line is the isolation transformer 240, and therefore, a detailed description of it will be omitted. Furthermore, although Fig. 15 illustrates that the fault detector 210 is installed on each branch, a configuration in which the fault detector 210 is installed only on the main line is also possible. Fig. 16 is a connection diagram in which a device for preventing electric shock and fire according to the present invention, including the detection / recovery device 230, is applied to the branch of the three-phase power supply. Referring to Fig. 16, the device for preventing electric shock and fire according to the present invention can be configured to include the isolation transformer 240 for isolating the earth branch provided in each branch line from the main grounded main transformer 300. In this case, the isolation transformer 240 is a three-phase transformer and can have a YY or Δ-Y connection structure. Furthermore, as illustrated in the load block of Fig. 16, the three-phase detection / recovery device 230 can be connected in parallel to the load 290 on the load side of at least one of the branches. In addition, the fault detector 210 may be provided with the ability to detect leakage current while limiting the leakage current to a predetermined or lesser dangerous current between earth and at least one of the branch power line PL2, the first neutral point N1, or the second neutral point N2 of the detection / recovery device 230 connected thereto. Furthermore, in order to protect the electrical installation 100 from the rear end of the isolation transformer 240 from overvoltage, the surge protector 280 can be installed between the ground and at least one of the power line PL2, the first neutral point N1, and the second neutral point N2. In the foregoing, the configuration and operation of the device to prevent an electric shock and a fire according to the present invention have been described. A method for preventing electric shock and fire during current leakage and earth fault according to the present invention may be configured to include isolating two or more power lines PL2 from an earth having a resistance value greater than or equal to a predetermined earth resistance value, detecting a leakage current between at least one of the two or more power lines PL2 and a first neutral point N1 having a potential between the voltages of the two or more power lines PL2 and earth, and emitting a detection signal according to the detection of the leakage current. Furthermore, the method for preventing an electric shock and fire according to the present invention may further include cutting off a power supply to the power line PL2 through which a leakage current flows intertwined with the detection signal of the fault detector 210, and restoring the cut-off power and supplying the restored cut-off power to the load 290. Here, energy recovery can be configured to include receiving energy from the PL2 energy line and the first neutral point N1 different from the PL2 energy line cut in the energy line cut, and recovering the cut energy using the energy received in the energy reception and supplying the recovered energy to load 290. The modalities in which the device for preventing electric shock and fire of the present invention limits a leakage current flowing into the earth through the human body or electrical installation to a dangerous current or less when the leakage current occurs due to current leakage or earth fault and detects the leakage current have been described. From here on, the modalities in which electric shock and fire can be prevented during current leakage and ground fault will be described as another modality of the device for preventing electric shock and fire of the present invention, fundamentally by cutting off the passage of leakage current through the human body or the electrical installation when leakage current occurs. Fig. 17 is a connection diagram illustrating a configuration of a device for preventing electric shock and fire during current leakage and earth fault according to a third embodiment of the present invention and a distribution system including the same. Referring to Fig. 17, the device for preventing electric shock and fire during leakage current and earth fault according to the present invention can be configured to include two or more power lines 1410 and 1420 that are electrically connected to the power supply unit 1100 to transmit AC or DC electricity from the power supply unit 1100 to a load installation and are isolated from earth by means of a resistance value greater than or equal to a predetermined earth resistance value, and the fault detector 210 is configured to detect if leakage current occurs between at least one of the neutral points N that have a potential between the voltages of the two or more power lines 1410 and 1420 and earth.In this case, fault detector 210 operates to ground the power lines 1410 and 1420 or the neutral point N where leakage current occurs between the two or more power lines 1410 and 1420 and the neutral point N when leakage current occurs. Referring to Fig. 17, the power distribution system according to the present invention is configured to include the above-described device to prevent electric shock and fire, the power supply unit 1100 which is configured to provide AC or DC electricity to the load facility, and the two or more power lines 1410 and 1420 are electrically connected to the power supply unit 1100 and isolated from earth with a resistance value greater than or equal to the predetermined earth resistance value. Power lines 1410 and 1420 are conductors that supply power from the power supply unit 1100 to the load side or peripheral power installations (hereafter referred to as the load installation). This is a collective term for all electrically connected conductors that transmit power, including not only individual conductors separated by circuit breaker 270 or switch, but also a branch line connected by circuit breaker 270, switch, equipment, etc., or branched off from the main line. In this case, it is preferable that power lines 1410 and 1420 be insulated from earth to have a resistance value greater than or equal to a predetermined earth resistance.Here, isolation is not limited to the case of complete isolation, and includes the case where the power lines 1410 and 1420 or the neutral point N have a resistance value greater than a normal ground resistance with the earth through a grounding electrode. The 1100 power supply unit is a component that supplies electricity to the 1410 and 1420 power lines and can be either a DC or AC power supply. When the power supply is DC, it can be solar or an energy storage system (ESS). When the power supply is AC, it can be single-phase, three-phase, or polyphase, with each phase having a predetermined phase difference. Hereafter, the AC power supply unit will be described as the third and fourth modes, and the DC power supply unit, such as solar, will be described as the fifth and sixth modes. The power distribution system according to the present invention may include a circuit breaker 1500 that controls the supply or cutting off of power to the power lines 1410 and 1420 interlocking with the detection result of the fault detector 210. Circuit breaker 1500 is to be controlled to isolate power supply unit 1100 from power lines 1410 and 1420 when fault detector 210 detects that a ground fault or leakage current has occurred on power lines 1410 and 1420. In particular, when leakage current occurs on the plurality of power lines 1410 and 1420, power supply unit 1100 can be controlled to isolate power lines 1410 and 1420. The fault detector 210 of the present invention detects if leakage current occurs, but may be electrically connected between at least one of the two or more power lines 1410 and 1420 and earth to identify the power lines 1410 and 1420 or the neutral point N where leakage current has occurred. The device for preventing electric shock and fire according to the present invention can be configured to include a grounding unit 1300 that is controlled to short-circuit to earth the power lines 1410 and 1420 in which leakage current occurs between the two or more power lines 1410 and 1420 according to the detection result of the fault detector 210, in order to ground the power lines 1410 and 1420. Additionally, when the power supply unit 1100 is a three-phase alternating current, the grounding unit 1300 can be configured to short-circuit to earth the neutral point N or the neutral line NL through which leakage current flows, in order to ground the neutral point N or the neutral line NL. The earth switching unit 1300 is electrically connected between at least one of the two or more power lines 1410 and 1420 or the neutral point N and earth to ground the power lines 1410 and 1420 or the neutral point N where the leakage current occurs according to the detection result of the fault detector 210 and allows the leakage current to flow without passing through the earth switching unit 1300 instead of flowing into the human body, peripheral installations, or the load installation, thereby fundamentally preventing electric shock or fire caused by the leakage current. Fig. 17 illustrates a device configuration for preventing electric shock and fire during current leakage and ground fault according to the third embodiment of the present invention in the case where the power supply unit 1100 is a single-phase alternating current, and a power distribution system including the same. Referring to Fig. 17, the device for preventing electric shock and fire and the power distribution system according to the third embodiment of the present invention may include the first and second fault detectors 210-1 and 210-2 that are electrically connected between the two power lines 1410 and 1420 and earth, respectively, and the earth switching unit 1300 may include first and second earth switches 1310 and 1320 whose switching off or on is controlled in response to each fault detector 210. In particular, in the configuration of the third embodiment of the present invention, the grounding switch can be electrically connected in parallel to the corresponding fault detector 210. In this case, the grounding switch is preferably a normally closed (NC) type switch that is turned off when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector 210. When a current leakage and ground fault occur on the first power line 1410 of the two power lines 1410 and 1420, the voltage across the first fault detector 210-1, connected between the first power line 1410 and the grounding electrodes, and therefore the current flowing in the fault detector, is less than or equal to a predetermined reference value, causing the first circuit breaker 1310 to short-circuit. Similarly, when a current leakage and ground fault occur on the second power line 1420, the voltage across the second fault detector 210-2, connected between the second power line 1420 and the grounding electrodes, and therefore the current flowing in the fault detector, is less than or equal to a predetermined reference value, causing the second grounding switch 1320 to short-circuit. As in the third embodiment of the present invention, when the ground switch is configured in a normally closed (NC) type, it is possible to detect even if the current leakage or ground fault occurs not only in one power line but also in a plurality of power lines. The fault detector 210 applied to the device to prevent electric shock and fire and a power distribution system according to the present invention can be configured to be electrically connected between at least one of the two or more power lines and the earth to detect if leakage current occurs from the power line to the earth. As described above in Figures 2A, 2B, and 2C, each fault detector 210 includes a current sensing unit 211 that detects the leakage current and outputs the detection signal. In this case, the fault detector 210 may include a current limiting device in which the resistance values ​​at both ends are set to be greater than or equal to a predetermined resistance value to limit the leakage current to a predetermined hazardous current or less. Furthermore, the fault detector 210 may be configured to also include a unidirectional current unit 212 that limits a path for the leakage current in a predetermined direction so that the leakage current flows through the current sensing unit 211 in only one direction. In the third embodiment of the present invention as illustrated in Fig. 17, the fault detector 210 having the structure illustrated in Fig. 2C can be used, and in the fourth embodiment of the present invention as illustrated in Figs. 22 and 23, as illustrated in Figs. 2A or 2B, the fault detector 210 having a structure that further includes the unidirectional current unit 212 can be used. From here on, the operating principle and configuration of the fourth mode of the present invention, to which the fault detector 210 of Fig. 2A or 2B is applied, and the third mode, to which the fault detector 210 of Fig. 2C is applied, will be described. Fig. 18 is a conceptual diagram to describe a normal state in the third embodiment of the present invention illustrated in Fig. 17. Figs. 19A, 19B and 20A, 20B are conceptual diagrams to describe an operation when an electrical fault or ground fault occurs in one of the power lines 1410 and 1420 in one phase. Figs. 21A and 21B are conceptual diagrams to describe an operation when a ground fault or current leakage occurs in the plurality of power lines 1410 and 1420 or two phases.The grounding switch in the device for preventing electric shock and fire, and the power distribution system according to the third embodiment of the present invention, is a normally closed (NC) type switch that is turned off when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector 210, and can be configured to be electrically connected in parallel to the same power lines 1410 and 1420 as the corresponding fault detector 210. Here, the fault detector 210 can detect when a current less than or equal to a predetermined reference value flows and controls the grounding switch to be short-circuited. Referring to Fig. 18, in the normal state, an operating current greater than or equal to a predetermined reference value flows in the first and second fault detectors 210-1 and 210-2, and each of the first and second fault detectors 210-1 and 210-2 is controlled to open the corresponding first and second ground switches 1310 and 1320, so that normal power is supplied to the load side through power lines 1410 and 1420. As illustrated in Fig. 19A, when leakage current and earth fault occur on a first power line 1410 of the two power lines 1410 and 1420, the voltage across the first fault detector 210-1 connected between the first power line 1410 and the earth taps, and therefore the current flowing in the first fault detector 210-1 is less than or equal to a predetermined threshold value, so that the first earth switch 1310 which is controlled by the first fault detector 210-1 is short-circuited. In this way, when the first power line 1410 in which the current leakage or earth fault has occurred is connected to earth by means of the first earth switch 1310, the leakage current 1 flowing from the first power line 1410 to earth flows into the earth through the first earth switch 1310 as illustrated in Fig. 19B instead of the human body, peripheral installation, or flammable object, so that electrical accidents such as electric shock or fire are fundamentally prevented. Furthermore, as illustrated in Fig. 20A, when current leakage and earth fault occur on the second power line 1420 of the two power lines 1410 and 1420, the voltage across the second fault detector 210-2 connected between the second power line 1420 and the earth taps, and therefore the current flowing in the second fault detector 210-2, is less than or equal to a predetermined reference value, so that the second earth switch 1320, which is controlled by the second fault detector 210-2, is short-circuited. In this way, when the second power line 1420 in which the earth fault or leakage current has occurred is connected to earth by means of the second earth switch 1320, the leakage current 2 that flows from the second power line 1420 to earth flows into the earth through the second earth switch 1320 instead of the human body, so that electrical accidents such as electric shock or fire are fundamentally prevented. Furthermore, when current leakage or earth fault simultaneously occur in the first and second power lines 1410 and 1420 as illustrated in Figs. 21A and 21B, due to all currents flowing through the first and second fault detectors 210-1 and 210-2 being less than or equal to a predetermined reference value, the first and second earth switches 1310 and 1320 controlled by the first and second fault detectors 210-1 and 210-2 can be controlled to be short-circuited. Furthermore, when a current leakage or earth fault is detected in the plurality of power lines 1410 and 1420 by the first and second fault detectors 210-1 and 210-2, as illustrated in Fig. 21B, the circuit breaker 1500 can be opened and controlled to cut off the power supply from the power supply unit 1100 to the power lines 1410 and 1420. Thus, when a current leakage or ground fault occurs in the plurality of power lines 1410 and 1420, before the circuit breaker 1500 interrupts the power supply, to prevent a short circuit between the power lines 1410 and 1420 due to the plurality of ground switches, a short-circuit protection device can be installed in series with the ground switch. Here, the short-circuit protection device can be an inductor to limit an instantaneous short-circuit current. Thus, in the same structure as the third embodiment of the present invention, the earth switch is configured in a normally closed (NC) type, so that the earth fault or leakage current can be detected even in the situation where the leakage current occurs not only in one of the power lines 1410 and 1420 but also in the plurality of power lines 1410 and 1420. Therefore, in the situation where the earth fault or leakage current is detected in the plurality of power lines 1410 and 1420, the circuit breaker 1500 is open / closed and can therefore be controlled to electrically isolate the power supply unit 1100 from the power lines 1410 and 1420. Fig. 22 is a connection diagram illustrating a configuration of a device for preventing electric shock and fire during current leakage and earth fault according to a fourth embodiment of the present invention and a distribution system including the same. In the device for preventing electric shock and fire according to the fourth embodiment of the present invention, unlike the third embodiment, when current leakage or earth fault occurs in power lines 1410 and 1420, the operating current due to leakage current flows into fault detector 210 to a predetermined reference value or higher, so that the corresponding earth switch is controlled by fault detector 210. For this purpose, the fault detector 210 in the device for preventing electric shock and fire according to the fourth embodiment of the present invention may be configured to include the unidirectional current unit 212 in which conduction is permitted only for leakage current flowing in specific power lines 1410 and 1420, and the grounding switch may be a normally open (NO, normally open) type switch that is turned on when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector 210. In this case, the grounding switch is electrically connected to at least one of the power lines 1410 and 1420 and the neutral point N, not the power lines 1410 and 1420 to which the corresponding fault detector 210 is connected between the two or more lines 1410 and 1420 and the neutral point N. Referring to Fig. 22, the device for preventing electric shock and fire and the power distribution system according to the fourth embodiment of the present invention can be configured to include the first and second fault detectors 210-1 and 210-2 that are electrically connected between the two power lines 1410 and 1420 and earth, respectively, and the first and second ground switches 1310 and 1320 whose switching on and off is controlled in response to each fault detector. As illustrated in Fig. 2A or 2B, each of the first and second fault detectors 210-1 and 210-2 can be configured to include the current sensing unit 211 that detects a leakage current and a one-way current unit 212 that limits a path of the leakage current so that the leakage current flows through the current sensing unit 211 in one direction. In particular, as illustrated in Fig. 22, when all current conduction directions of the unidirectional current units 212 of each of the first and second fault detectors 210-1 and 210-2 are configured to flow from or flow into the earth, in the normal state where leakage current or earth fault does not occur, leakage current does not flow into fault detector 210, and only when leakage current occurs in either of the first and second power lines 1410 and 1420, does fault detector 210 detect the leakage current and operate the corresponding earth switch. The ground switch is a normal open (NO) type switch in which a contact is short-circuited by a detection signal emitted when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector 210, and is electrically connected to power lines 1410 and 1420, not the power lines 1410 and 1420 to which the corresponding fault detector 210 is connected. In other words, when the first fault detector 210-1 is connected between the first power line 1410 and earth, and the second fault detector 210-2 is connected between the second power line 1420 and earth, the first ground switch 1310 corresponding to the first fault detector 210 can be installed between the second power line 1420 and earth, and the second ground switch 1320 corresponding to the second fault detector 210-2 can be installed between the first power line 1410 and earth. Fig. 23 is a conceptual diagram to describe an operation when current leakage or ground fault occurs in one phase in the fourth embodiment of the present invention illustrated in Fig. 22. Referring to Fig. 23, when leakage current and earth fault occur in the first power line 1410 of the two power lines 1410 and 1420 and therefore leakage current 1 flows, leakage current 1 flows in the second fault detector 210-2 connected between the second power line 1420 and earth to a predetermined reference value or higher, so that the second switch 1320 is controlled to ground the first power line 1410 to earth by means of the second fault detector 210-2 which has detected leakage current 1. In this way, when the first power line 1410 in which the current leakage or earth fault occurred is connected to earth by the second earth switch 1320, the leakage current 1 flowing from the first power line 1410 to earth flows into the earth through the second earth switch 1320 instead of the human body, peripheral installation, or flammable object, so that electrical accidents such as electric shock or fire are fundamentally avoided. Furthermore, when leakage current and earth fault occur in the second power line 1420 of the two power lines 1410 and 1420, and therefore leakage current 2 flows into the first fault detector 210-1 connected between the first power line 1410 and earth at the predetermined reference value or higher, therefore the first earth switch 1310 is controlled to ground the second power line 1420 to earth by means of the first fault detector 210-1 which detects leakage current 2. In this way, when the second power line 1420 in which the current leakage or earth fault occurred is connected to earth by means of the first earth switch 1310, the leakage current 2 flowing from the second power line 1420 to earth flows into the earth through the first earth switch 1310 instead of the human body, peripheral installation, or flammable object, thus fundamentally preventing electrical accidents such as electric shock or fire. In the foregoing, the third and fourth embodiments of the present invention have been described taking the case where the 1100 power supply unit is the single-phase AC power supply as an example, but the technical idea of ​​the present invention is not limited to it, and the third and fourth embodiments of the present invention can be applied to a DC circuit as well as a polyphase AC circuit including the three-phase AC circuit. As an example, the configuration when the third and fourth modes of the present invention are applied to a three-phase AC circuit will be described. Fig. 24 is a connection diagram when the configuration according to the third modality of the present invention is applied to a three-phase AC power supply. Referring to Fig. 24, in the device for preventing electric shock and fire and distribution system according to a third embodiment of the present invention, the power supply unit 1100 is a three-phase AC power source including phase-R, phase-S, and phase-T; the fault detector 210 includes first to third fault detectors 210-1, 210-2, and 210-3 respectively connected between phase-R, phase-S, and phase-T and earth; the earth switching unit 1300 includes first to third earth switches 1310, 1320, and 1330 corresponding to first to third fault detectors 210-1, 210-2, and 210-3 respectively; and first to third earth switches 1310, 1320, and 1330 are normally closed (NC) type switches that operate when an operating current greater than or equal to a value The default reference flows into the corresponding fault detector 210 for open contacts. In this case, the first to third earth switches 1310, 1320, and 1330 can be installed between the plurality of power lines 1410, 1420, 1430 and earth so that the corresponding power line is connected to earth when leakage current or earth fault occurs in one or more of the first to third power lines 1410, 1420, and 1430 connected to phase-R, phase-S, and phase-T, and more specifically, the first to third earth switches 1310, 1320, and 1330 can be configured to be connected in parallel to each of the corresponding fault detectors 210. As described above, in the three-phase AC circuit to which the configuration according to the third embodiment of the present invention applies, when leakage current and earth fault occur in any of the first to third power lines 1410, 1420, and 1430, the voltage across the fault detector 210 connected between the corresponding power line and the earth taps, and therefore the current flowing in the fault detector 210 is less than or equal to a predetermined reference value, hence the earth switch controlled by the corresponding fault detector 210 is short-circuited. In this way, when power lines 1410, 1420, and 1430 in which current leakage or earth fault has occurred are connected to earth by means of the earth switch, the leakage current flowing from power lines 1410, 1420, and 1430 to earth flows into the earth through the short-circuited earth switch instead of the human body, peripheral installation, or flammable object, thus fundamentally preventing electrical accidents such as electric shock or fire. Furthermore, when leakage current or earth fault occurs simultaneously in the plurality of power lines between the first to third power lines 1410, 1420, and 1430, because all the currents flowing in the fault detector 210 connected to the power lines 1410, 1420, and 1430 in which the leakage current or earth fault has occurred are less than or equal to a predetermined reference value, the earth switches controlled by the corresponding fault detector 210 are short-circuited, therefore the power lines 1410, 1420, and 1430 with the leakage current and earth fault can be controlled to be connected to earth.Furthermore, when a current leakage or earth fault is detected in the plurality of power lines 1410, 1420, and 1430 by means of fault detector 210, the circuit breaker 1500 installed between the power supply unit 1100 and the first to third power lines 1410, 1420, and 1430 opens and can therefore be controlled to cut off the power supply from the power supply unit 1100 to the power lines 1410, 1420, and 1430. As such, when current leakage or earth fault occurs in the plurality of power lines 1410, 1420, and 1430, in order for the operation of the plurality of earth switches to prevent the power lines 1410, 1420, and 1430 from instantaneously short-circuiting each other before the circuit breaker 1500 cuts off the power supply, the short-circuit protection device may be installed in series with the earth switch and the short-circuit protection device may be an inductor device to limit an instantaneous short-circuit current. As described above, in the same structure as the third embodiment of the present invention, the grounding switch is configured in the normally closed (NC) type, so that the situation where a ground fault or leakage current occurs not only on one of the power lines 1410, 1420, and 1430 but also on a plurality of power lines 1410, 1420, and 1430 can be detected. Therefore, when a ground fault or leakage current is detected on a plurality of power lines 1410, 1420, and 1430, the circuit breaker 1500 opens and can thus be controlled to electrically isolate the power supply unit 1100 from the power lines 1410, 1420, and 1430. Fig. 25 is a connection diagram when the configuration according to the fourth modality of the present invention is applied to the three-phase power supply. Referring to Fig. 25, in the device for preventing electric shock and fire and distribution system according to the fourth embodiment of the present invention, the power supply unit 1100 is a three-phase AC power source including phase-R, phase-S, and phase-T; the fault detector 210 includes first to third fault detectors 210-1, 210-2, and 210-3 respectively connected between phase-R, phase-S, and phase-T and earth; the earth switching unit 1300 includes first to third earth switches 1310, 1320, and 1330 corresponding to first to third fault detectors 210-1, 210-2, and 210-3 respectively; and first to third earth switches 1310, 1320, and 1330 are normally open (NO) type switches that are activated when an operating current greater than that or equal to a predetermined reference value flows into the corresponding fault detector 210 to short-circuit contacts. In this case, the first to third ground switches 1310, 1320, and 1330 can be installed between the plurality of power lines 1410, 1420, and 1430 and earth so that the corresponding power lines 1410, 1420, and 1430 are connected to earth when leakage current or earth fault occurs in one or more power lines 1410, 1420, and 1430 of the first to third power lines 1410, 1420, and 1430 connected to phase-R, phase-s, and phase-T. In addition, the first to third earth switches 1310, 1320, and 1330 can be installed between the neutral line NL and earth so that NL neutral is grounded to earth when leakage current or electrical fault occurs in NL neutral connected to the neutral point N of phases R, S, and T. As illustrated in Fig. 2A or 2B, each of the first to third fault detectors 210-1, 210-2, and 210-3 can be configured to include the current sensing unit 211 that detects a leakage current and a one-way current unit 212 that limits a path of the leakage current so that the leakage current flows through the current sensing unit 211 in one direction. In particular, as illustrated in Fig. 25, when all current conduction directions of the unidirectional current units 212 of each of the first to third fault detectors 210-1, 210-2, and 210-3 are configured to flow from or into earth, in the normal state where leakage current or earth fault does not occur, leakage current does not flow into fault detector 210, and only when leakage current occurs in any of 1410, 1420, or 1430 of the first to third power lines 1410, 1420, and 1430, does fault detector 210 detect the leakage current and operate the corresponding earth switch. The ground switch is a normally open (NO) type switch in which a contact is short-circuited by means of a detection signal emitted when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector 210, and is electrically connected to power lines 1410, 1420, and 1430, not the power lines 1410, 1420, and 1430 to which the corresponding fault detector 210 is connected. In other words, when a current leakage or earth fault occurs in any of the first to third power lines 1410, 1420, and 1430, and therefore leakage current flows because the operating current greater than or equal to a predetermined reference value flows in the remaining fault detectors 210 other than fault detector 210 connected to the power lines 1410, 1420, and 1430 in which the current leakage or earth fault has occurred between the first to third fault detectors 210-1, 210-2, and 210-3, the earth switch can be arranged so that the power lines 1410, 1420, and 1430 with the current leakage or earth fault can be connected to earth by means of the use of earth switch interleaving with the signal from the remaining fault detectors 210. For example, referring to Fig. 25, assuming that the first to third fault detectors 210-1, 210-2, and 210-3 are respectively connected between the first to third power lines 1410, 1420, and 1430 and earth, the second and third ground switches 1320 and 1330 corresponding to the second and third fault detectors 210-2 and 210-3 can be connected in series between the first power line 1410 and earth, the first and third ground switches 1310 and 1330 corresponding to the first and third fault detectors 210-1 and 210-3 can be connected in series between the second power line 1420 and earth, and the first and second ground switches 1310 and 1320 corresponding to the first and second fault detectors 210-1 and 210-2 can be connected in series between the third power line 1430 and the earth. Furthermore, when the neutral point N or the neutral line NL is short-circuited or has an earth fault, leakage current flows to all of the first to third fault detectors 210-1, 210-2, and 210-3, so that the first to third earth switches 1310, 1320, and 1330 can be connected in series between the neutral line NL and earth. However, the connection configuration of Fig. 25 is only one example according to the fourth embodiment of the present invention, and in order to ground the power lines 1410, 1420, 1430 or the neutral line NL in which the current leakage or earth fault occurs, various methods and configurations can be devised, such as logically calculating the detection result of the fault detector 210. According to the fourth embodiment of the present invention, when current leakage or earth fault occurs in the power lines 1410, 1420, and 1430 or the neutral line NL in the three-phase AC circuit, because the corresponding power lines 1410, 1420, and 1430 or the neutral line NL can be connected to earth, since the leakage current flowing from the power lines 1410, 1420, and 1430 or the neutral line NL to earth flows to earth through the earth switch instead of the human body, peripheral installations, or flammable object, in this way electrical accidents such as electric shock or fire are fundamentally avoided. Furthermore, the power distribution system according to the present invention may also include a surge protector (not illustrated) that is electrically connected between at least one of the two or more power lines 1410, 1420, and 1430 and the neutral point N, which has a potential between the voltages of the two or more power lines 1410, 1420, and 1430 and earth. The surge protector may be installed between each of the power lines 1410, 1420, and 1430 and earth in parallel with the fault detector 210, and may also be installed between the neutral point N or the neutral line NL and earth to suppress surge voltages introduced into the supply lines 1410, 1420, and 1430 or the neutral line NL. In this case, the device for preventing electric shock and fire according to the present invention can be configured to detect leakage current due to a defect, deterioration, or failure of the surge protector, thereby recognizing the defects, deterioration, or failure of the surge protector. The surge protector is a component that protects peripheral installations by suppressing an abnormal surge voltage introduced into the 1410, 1420, 1430 power lines and the NL neutral line by lightning, etc., and can be configured to include a varistor. Due to the deterioration or failure of the surge protector and the introduction of an overvoltage exceeding its rated capacity, the surge protector's impedance decreases. Consequently, leakage current can flow even under normal conditions, similar to the occurrence of a ground fault or leakage current. In this case, the device for preventing electric shock and fire according to the present invention can detect the leakage current due to the defect, deterioration, or failure of the surge protector, recognize the defect, deterioration, or failure, and notify a responsible party. The responsible party can then appropriately replace the surge protector. Furthermore, the device for preventing electric shock and fire during current leakage and ground fault according to the present invention can be applied not only to an AC circuit but also to a DC circuit such as sunlight. The methods by which the device for preventing electric shock and fire according to the present invention is applied to a photovoltaic power generation system will now be described. Fig. 26 is a block diagram illustrating the overall configuration of a photovoltaic power generation system including the device to prevent electric shock and fire during current leakage and ground fault according to the present invention. Referring to Fig. 26, the device for preventing electric shock and fire in the photovoltaic power generation system includes at least one fault detector 210 that is configured to be electrically connected to a solar panel 2100 to transmit electricity generated from the solar panel 2100 in which one or more solar cell modules 2110 are arranged, to the load installation 2500 and detects if leakage current occurs between two or more power lines 2410 isolated from earth with a resistance value greater than or equal to a predetermined ground resistance value and earth, and the fault detector 210 operates to ground, to earth, a power line 2410 in which leakage current has occurred between two or more power lines 2410 when leakage current occurs. Herein, the voltaic power generation system according to the present invention may be configured to include the solar panel 2100 in which one or more solar cell modules 2110 are arranged, two or more power lines 2410 that are electrically connected to the solar panel 2100 to transmit the electricity generated from the solar panel 2100 to the charging installation 2500 and are insulated from the earth with a resistance value greater than or equal to a predetermined earth resistance value, and the device described above to prevent electric shock and fire. The 2410 power line is a conductor that supplies power from the 2100 solar panel to the load or peripheral power installation (hereafter referred to as the load installation). It is a collective term for all conductors electrically connected to each other to transmit power, including not only conductors separated by a circuit breaker or switch, but also a branch circuit connected by a circuit breaker, switch, or other equipment, or branched off from the main line. In this case, it is preferable for the 2410 power line to be insulated from earth to have a resistance value greater than or equal to a predetermined earth resistance. Here, the insulation is not limited to complete isolation and includes cases where the 2410 power line or the neutral point (N) has a resistance value greater than a normal earth resistance, with the earth grounded through an earthing electrode. The circuit of the 2500 letter installation connected to the 2410 power line can be either a DC or AC circuit. In the case of a DC circuit, the 2410 power line may include a DC power line connected to the 2100 solar panel and the energy storage system (ESS). In the case of an AC circuit, it may include an AC power line connected to an inverter output that converts direct current to alternating current. Referring to Fig. 26, the photovoltaic power generation system includes a collection unit 2430 that collects a current generated from each of the solar cell modules 2110 when two or more solar cell modules 2110 are arranged in a solar panel 2100. The DC current collected by means of the collection unit 2430 is transmitted to the load installation 2500 through the DC power line 2410. In addition, the photovoltaic power generation system may include a DC circuit breaker 2420 that is arranged between the solar cell module 2110 and the collection unit 2430, and controls the opening and closing by interleaving with the detection signal from the fault detector 210. The DC circuit breaker 2420 can be one or more circuit breakers corresponding to the solar cell module 2110. In this case of multiple circuit breakers, the multiple DC circuit breakers 2420 can confirm signal detection while simultaneously or sequentially cutting off all of them, interleaving with the fault detector 210 detection signal to cut off only the solar cell module 2100 in which the leakage current occurs. The DC circuit breaker 2420 can be controlled to disconnect the solar cell module 2110 from the power line 2410 when the fault detector 210 detects that a ground fault or current leakage has occurred on two or more power lines 2410. The collection unit 2430 and the DC circuit breaker 2420 described above can be installed on the connector strip 2400. The connector strip 2400 can be configured to also include the fault detector 210 and the earth switch unit 1300, which will be described later. The device for preventing an electric shock and fire in the photovoltaic power generation system according to the present invention can be configured to further include the ground switching unit 1300 which is controlled to short-circuit to ground the power line 2410 in which leakage current occurs between the two or more power lines 2410 according to the detection result of the fault detector 210 to ground the power line 2410. The earth-switching unit 1300 is electrically connected between at least one of the two or more power lines 2410 and earth to earth the power line 2410 in which the leakage current occurs according to the detection result of the fault detector 210, and allows the leakage current to flow without passing through the earth-switching unit 1300 instead of flowing into the human body, peripheral installations, or the load installation 2500, thereby fundamentally preventing electric shock or fire caused by the leakage current. For this purpose, the fault detector 210 of the present invention can be configured to detect whether leakage current has occurred, but to identify the power line 2410 in which leakage current has occurred. The fault detector 210 applied to the device to prevent an electric shock and fire of the photovoltaic power generation system according to the present invention can be configured to be electrically connected between at least one of the two or more power lines 2410 and the neutral point N having the potential between the voltages of the two or more power lines 2410 and the earth to detect if leakage current occurs from the power line 2410 to the earth. As described above in Figures 2A, 2B, and 2C, each fault detector 210 includes a current sensing unit 211 that detects the leakage current and outputs the detection signal. In this case, the fault detector 210 may include a current limiting device in which the resistance value at both ends is set to be greater than or equal to a predetermined resistance value to limit the leakage current to a predetermined or lower dangerous current. Furthermore, as illustrated in Figures 2A and 2B, the fault detector 210 may be configured to also include a unidirectional current unit 212 that limits the path for the leakage current in a predetermined direction so that the leakage current flows through the current sensing unit 211 in only one direction. The fault detector 210, configured to include the unidirectional current unit 212, can be installed on the power line 2410 or at a neutral point N to identify the power line 2410 through which the leakage current flows, based on the direction of the leakage current. In this case, the fault detector 210 can detect which of the two or more power lines 2410 the leakage current occurs on, using the unidirectional current unit 212 configured to detect leakage current flow in different directions. Furthermore, the fault detector 210 according to the present invention can be configured to detect the power line 2410 in which the leakage current occurred without using the unidirectional current unit 212. Referring to Fig. 2C, the current detection unit 211 can be configured to identify the direction of leakage current flowing through the fault detector 210. For example, as illustrated in Fig. 2C, the current detection unit 211 can emit different types of detection signals, i.e., detection signals of different polarities, depending on the direction of the leakage current, and control the ground switching unit 1300 to identify the power line 2410 through which the leakage current flows based on the detection signals and short-circuit the corresponding power line 2410 to ground. From here on, an example of the installation of fault detector 210 will be described, which identifies the power line 2410 through which leakage current flows in the photovoltaic power generation system. Fig. 27 is a connection diagram illustrating an example in which the fault detector 210 is connected to the power line 2410 according to a fifth embodiment of the present invention. Referring to Fig. 27, in the device for preventing electric shock and fire in the photovoltaic power generation system according to the present invention, two or more power lines 2410 may include the first and second DC power lines 2411 and 2412 that transmit the DC electricity generated from the solar panel 2100, the fault detector 210 may be configured to include the first and second fault detectors 210-1 and 210-2 that have one end electrically connected to the first and second DC power lines 2411 and 2412 to detect leakage current from the current path forming the current path for leakage current flowing to earth, and the ground switching unit 1300 that is controlled to short-circuit, to earth,the power line 2410 in whose leakage current occurs between the two or more power lines 2410 according to the detection result of fault detectors 210-1 and 210-2 to ground the power line 2410., Here, the earth switching unit 1300 can be configured to include the first switch 1310 which is controlled to ground the second power line CD 2412 to earth when leakage current flows in the second power line CD 2412 according to the detection result of fault detectors 210-1 and 210-2, and the second earth switch 1320 which is controlled to ground the first power line CD 2411 to earth when leakage current flows in the first power line CD 2411 according to the detection result of fault detectors 210-1 and 210-2. In addition, the earth-switching unit 1300 may further include a first voltage drop unit 2220-1 that is connected in series with the first fault detector 210-1 and electrically connected between the first power line CD 2411 and earth, and a second voltage drop unit 2220-2 that is connected in series with the second fault detector 210-2 and is electrically connected between the second power line C 2412 and earth. The first and second DC power lines 2411 and 2412 are power lines through which a DC current flows, and a voltage of a first polarity can be applied to the first DC power line 2411 and a voltage of a second polarity can be applied to the second DC power line 2412. Specifically, the first polarity can be a positive pole of the DC voltage and the second polarity can be a negative pole of the DC voltage, and vice versa. The first and second voltage drop units 2220-1 and 2220-2 have a component that is conducted when applied with a predetermined voltage or more or causes a predetermined voltage drop so that the current flowing to the fault detectors 210-1 and 210-2 in a normal state becomes less than or equal to a predetermined reference value, and can be a resistor or a Zener diode, but is not limited to them. In the configuration illustrated in Fig. 27, when the first and second voltage drop units 2220-1 and 2220-2 are configured to be conducted when applied with a predetermined voltage or more as a Zener diode, each of the conduction voltages of the first voltage drop unit 2220-1 and the second voltage drop unit 2220-2 is smaller than the voltage across the first and second power lines in series, and the sum of the conduction voltages of the first voltage drop unit 2220-1 and the second voltage drop unit 2220-2 is preferably greater than the voltage across the first and second power lines in series. When the conduction voltages of the first voltage drop unit 2220-1 and the second voltage drop unit 2220-2 are set as above, in the normal state in which leakage current does not occur, because the first voltage drop unit 2220-1 and the second voltage drop unit 2220-2 do not conduct and therefore no current flows in fault detectors 210-1 and 210-2, it is determined that leakage current does not occur, and in the situation in which leakage current does occur, because one of the first voltage drop unit 2220-1 and the second voltage drop unit 2220-2 is conducted and therefore leakage current flows in fault detectors 210-1 and 210-2, it is detected that leakage current has occurred. More specifically, when a ground fault or leakage current occurs on the first power line CD 2411, the second voltage drop unit 2220-2 is conducted to detect the leakage current in the second fault detector 210-2. When a ground fault or leakage current occurs on the second power line CD 2412, the first voltage drop unit 2220-1 is conducted to detect the leakage current in the first fault detector 210-1, thereby identifying the power line on which the ground fault or leakage current occurs. Thus, when a ground fault or leakage current occurs on the first power line CD 2411, the second grounding switch 1320 can be controlled to ground the first power line CD 2411 to earth via the second fault detector. 210-2, and when the ground fault or leakage current occurs on the second CD 2412 power line, the first ground switch 1310 can be controlled to ground the second CD 2412 power line to earth by means of the first fault detector 210-1. Similarly, when the first and second voltage drop units 2220-1 and 2220-2 are configured so that the current flowing in the fault detectors 210-1 and 210-2 in the normal state is less than or equal to a predetermined reference value, in the normal state in which leakage current does not occur, the current flowing in the fault detectors 210-1 and 210-2 is less than or equal to a predetermined reference value to determine that leakage current does not occur, and in the situation in which leakage current occurs, the current flowing in either of the first and second fault detectors 210-1 and 210-2 is greater than or equal to a predetermined reference value to detect that leakage current occurs. More specifically, when the ground fault or leakage current occurs on the first power line CD 2411, the current flowing in the second fault detector 210-2 is greater than or equal to a predetermined reference value for detecting leakage current, and when the ground fault or leakage current occurs on the second power line CD 2412, the current flowing in the first fault detector 210-1 is greater than or equal to a predetermined reference value for detecting leakage current, thereby identifying the power line on which the ground fault or leakage current occurs.In this way, when a ground fault or current leakage occurs in the first power line CD 2411, the second ground switch 1320 can be controlled to ground the first power line CD 2411 to earth by means of the second fault detector 210-2, and when a ground fault or current leakage occurs in the second power line CD 2412, the first ground switch 1310 can be controlled to ground the second power line CD 2412 to earth by means of the first fault detector 210-1. In this way, by grounding the power line 2410, identifying that a leakage current has occurred by means of fault detectors 210-1 and 210-2 to earth, the leakage current flows by avoiding the ground switching unit 1300 instead of flowing into the human body, peripheral installation, or load installation 2500, thus fundamentally preventing electric shock or fire caused by the leakage current. In order for the power line 2410 to detect the occurrence of leakage current even when leakage current occurs for one or both lines, although not illustrated in the figures, in the device for preventing electric shock and fire in the photovoltaic power generation system according to the present invention, the first and second fault detectors 210-1 and 210-2 can be configured so that, in the normal state, an operating current flows at a predetermined or higher reference value, and when leakage current occurs, an operating current flows in the fault detectors 210-1 and 210-2 connected to the DC power line, in which the leakage current flows, at a predetermined or lower reference value.In this case, the grounding unit 1300 includes the second grounding switch 1320 which is electrically connected between the first power line CD 2411 and earth, and the first grounding switch 1310 which is electrically connected between the second power line CD 2412 and earth, and the first and second grounding switches 1310 and 1320 may be a normally closed (NC) type which is closed in a non-operating state. For example, in this structure, in the normal state, when it is determined that the operating current greater than or equal to the predetermined reference value flows in fault detectors 210-1 and 210-2 and therefore the leakage current does not occur, the NC type 1300 grounding unit operates to open contacts, and in the situation in which the leakage current occurs, when it is detected that the current flowing through either of the first and second fault detectors 210-1 and 210-2 is less than or equal to a predetermined reference value and therefore the leakage current has occurred, the grounding unit 1300 may not operate to ground the corresponding power line to earth. In other words, when the ground fault or current leakage occurs on the first power line CD 2411, the current flowing in the first fault detector 210-1 is less than or equal to a predetermined reference value, and when the ground fault or current leakage occurs on the second power line CD 2412, the current flowing in the second fault detector 210-2 is less than or equal to a predetermined reference value, thus making it possible to identify the power line with the ground fault or current leakage.Thus, when a ground fault or leakage current occurs in the first power line CD 2411, the second ground switch 1320 is in a non-operating mode by the first fault detector 210-1 and can therefore be controlled to ground the first power line CD 2411 to earth, and when a ground fault or leakage current occurs in the second power line CD 2412, the first ground switch 1310 is in a non-operating mode by means of the second fault detector 210-2 and can therefore be controlled to ground the second power line CD 2412 to earth. In this configuration, even when leakage current occurs on one or two lines of power line 2410 due to a ground fault or leakage current, the leakage current can be detected. Therefore, when a ground fault or leakage current is detected on two lines, the DC circuit breaker 2420 opens and closes, allowing it to electrically isolate solar panel 2100 from power line 2410. In the above, the modality in which the fault detector 210 is installed between the power line 2410 and the earth has been described, but in order to detect the leakage current of the power line 2410, the fault detector 210 can be installed between the neutral point N which has a potential between voltages of two or more power lines 2410 and the earth. Figures 28A and 28B are a connection diagram illustrating an example in which fault detectors 210-1 and 210-2 are connected to the neutral point N according to a sixth embodiment of the present invention. The neutral point N refers to a point that has a potential between the voltages of two or more 2410 power lines. It can be formed from each 2410 power line through a voltage drop unit, including a predetermined electrical device, or it can be directly taken from a connection point between a plurality of 2110 solar cell modules connected in series between the 2410 power lines. It is sufficient if the sum of the 2410 power line voltages with respect to the neutral point N is 0, and the magnitudes of the 2410 power line voltages with respect to the neutral point N are not necessarily the same. Hereafter, for convenience of description, the description will be made with the understanding that the 2410 power line voltages have the same magnitude except that the phases are different with respect to the neutral point N. Referring to Figs. 28A and 28B, the fault detector 210 in the device for preventing electric shock and fire in the photovoltaic power generation system according to the present invention is electrically connected between the neutral point N, which has a potential between the voltages of two or more power lines 2410, and ground. By forming the current path for the leakage current flowing to ground, it is possible to detect the leakage current along this path. In this case, the fault detector 210 can identify the power line 2410 in which the leakage current has occurred between two or more power lines 2410, according to the direction in which the leakage current flows through the fault detector 210. Referring to Fig. 28A, the device for preventing electric shock and fire in the photovoltaic power generation system according to the present invention is configured to include a first voltage drop unit 2220-1 that is electrically connected between the first DC power line 2411 and the neutral point N and a second voltage drop unit 2220-2 that is electrically connected between the second DC power line 2412 and the neutral point N. In the configuration of Fig. 28A, the neutral point N is formed as a connection point for the first and second voltage drop units 2220-1 and 2220-2, and the first and second fault detectors are connected in parallel between the neutral point N and the ground formed in this way. In this case, the neutral point N has a potential between the voltages of the first and second DC power lines 2411 and 2412. In this structure, the leakage current between the first power line CD 2411 and earth passes through the second fault detector 210-2, and the current conduction direction of the one-way current unit 212 included in the fault detectors 210-1 and 210-2 can be set so that the leakage current between the second power line CD 2412 and earth passes through the first fault detector 210-1. In the mode of Fig. 28A, the first and second voltage drop units 2220-1 and 2220-2 have a configuration in which a predetermined voltage drop occurs when conducted, and may be a configuration that includes a resistor or a Zener diode, but is not limited to these. In the configuration of Fig. 28A, when the ground fault or leakage current occurs in the first power line CD 2411, because the leakage current is detected by means of the second fault detector 210-2 through the second voltage drop unit 2220-2, and when the ground fault or leakage current occurs in the second power line CD 2412, the leakage current is detected by means of the first fault detector 210-1 through the first voltage drop unit 2220-1, confirming from which fault detectors 210-1 and 210-2 the detection signal is generated, it is possible to identify the power line with the ground fault or leakage current. In this way, when a ground fault or current leakage occurs in the first power line CD 2411, the second ground switch 1320 can be controlled to ground the first power line CD 2411 to earth by means of the second fault detector 210-2, and when a ground fault or current leakage occurs in the second power line CD 2412, the first ground switch 1310 can be controlled to ground the second power line CD 2412 to earth by means of the first fault detector 210-1. In this way, by grounding the power line 2410, it was identified that the leakage current had occurred by means of fault detectors 210-1 and 210-2 to the ground. The leakage current flows without passing to the ground switching unit 1300 instead of flowing into the human body, peripheral installation, or load installation 2500, thus fundamentally preventing electric shock or fire caused by the leakage current. Furthermore, in the structure of Fig. 28B, the neutral point N can be extracted from a connection point between two or more solar cell modules 2110 connected in series between the first and second DC power lines 2411 and 2412. In this case, the fault detector 210 is configured to include the first and second fault detectors 210-1 and 210-2 connected in parallel between the neutral point N and earth, and the current conduction direction of the unidirectional current unit 212 included in the fault detectors 210-1 and 210-2 can be set so that the leakage current between the first DC power line 2411 and earth passes through the second fault detector 210-2, and the leakage current between the second DC power line 2412 and earth passes through the first fault detector 210-1. Similar to the configuration in Fig. 28A, when a ground fault or leakage current occurs in the first power line CD 2411, because the leakage current is detected by the second fault detector 210-2 through the second voltage drop unit 2220-2, and when a ground fault or leakage current occurs in the second power line CD 2412, the leakage current is detected by the first fault detector 210-1 through the first voltage drop unit 2220-1, confirming from which fault detectors 210-1 and 210-2 the detection signal is generated, it is possible to identify the power line with the ground fault or leakage current. In this way, when a ground fault or current leakage occurs in the first power line CD 2411, the second ground switch 1320 can be controlled to ground the first power line CD 2411 to earth by means of the second fault detector 210-2, and when a ground fault or current leakage occurs in the second power line CD 2412, the first ground switch 1310 can be controlled to ground the second power line CD 2412 to earth by means of the first fault detector 210-1. In the foregoing, the plurality of fault detectors 210-1 and 210-2 are installed between the neutral point N and earth, and each fault detector 210-1 and 210-2 is configured to detect a current in a specific direction by means of the unidirectional current unit 212. However, the device for preventing an electric shock and fire of the photovoltaic power generation system according to the present invention can be configured to detect the power line 2410 in which the leakage current has occurred using the fault detector 210 excluding the unidirectional current unit 212. For example, in the fault detector 210 illustrated in Fig. 2C, the current sensing unit 211 can emit different types of sensing signals, i.e., sensing signals of different polarities, depending on the direction of the leakage current, and controls the ground switching unit 1300 to identify the power line 2410 through which the leakage current flows and short-circuits the corresponding power line 2410 to ground. Figs. 29A and 29B are a connection diagram illustrating another example in which the fault detector 210 is connected to the neutral point N according to the sixth embodiment of the present invention. Referring to Figs. 29A and 29B, the fault detector 210 in the device for preventing electric shock and fire in the photovoltaic power generation system according to the present invention is electrically connected between the neutral point N having a potential between the voltages of the two or more power lines 2410 and the earth, and forming the current path for the leakage current flowing to the earth, it is possible to detect the leakage current from the current path. In this case, the fault detector 210 can emit a detection signal of a different type, i.e., a detection signal having a different polarity or a different level depending on the direction of the leakage current flowing through the fault detector 210, and controls the ground switching unit 1300 to identify the power line 2410 through which the leakage current flows and short-circuits the corresponding power line 2410 to ground.In other words, a current in a first direction flows to fault detector 210 due to the leakage current generated in the first power line, and a current in a second direction flows to fault detector 210 due to the leakage current generated in the second power line; therefore, fault detector 210 can operate the second ground switch 1320 with respect to the current in the first direction and operates the first ground switch 1310 with respect to the current in the second direction to ground the corresponding power line to earth. By grounding the power line 2410, it was identified that leakage current has occurred. Depending on the direction of current flowing in fault detector 210, the leakage current flows without passing to the ground switching unit 1300 instead of flowing into the human body, peripheral installation, or load installation 2500, thereby fundamentally avoiding electric shock or fire caused by leakage current. As described above, the neutral point N to which the fault detector 210 is connected refers to a point that has a potential between the voltages of the two or more power lines 2410, and as illustrated in Fig. 29A, the neutral point N can be formed from each of the power lines 2410 through the voltage drop unit including a predetermined electrical device, and as illustrated in Fig. 29B, directly drawn from the connection point between the plurality of solar cell modules 2110 connected in series between the power lines 2410. Figs. 30A and 30B are a conceptual diagram illustrating the principle of fault detector 210 by detecting leakage current and grounding power line 2410 to earth in the mode illustrated in Figs. 29A and 29B. In Figs. 30A and 30B, the operating principle of the fault detector 210, which detects leakage current and does not pass the leakage current to the ground switching unit 1300, is described in the case where the photovoltaic power generation system of the present invention has the configuration of Fig. 29A, but the operating principle can be understood in the same way for the configuration of Figs. 27, 28A, 28B and 29B. According to Fig. 30A, the leakage current 1 generated in the first DC power line 2411 between the DC power lines forms a current path that flows through the fault detector 210 in the first direction along the solid line illustrated in the figure, and the leakage current 2 generated in the second DC power line 2412 between the DC power lines forms a current path that flows through the fault detector 210 in the second direction along the dashed line. Here, because leakage current flows through the human body, peripheral electrical installations, etc., even if the magnitude of the leakage current is limited to a predetermined dangerous current or less by means of the fault detector 210, the risk of electric shock or fire still remains. Referring to Fig. 30B in the photovoltaic power generation system according to the present invention, fault detector 210 can operate in turn on the second ground switch 1320 for leakage current 1, and fault detector 210 can operate to turn on the first ground switch 1310 for leakage current 2. In this way, leakage current 1 generated in the first DC power line 2411 and flowing to the human body or peripheral electrical installations bypasses the second ground switch 1320 and flows to ground, and leakage current 2 generated in the second DC power line 2412 and flowing to the human body or peripheral electrical installations bypasses the first ground switch 1310 and flows to ground. Therefore, the device for preventing electric shock and fire from the photovoltaic power generation system according to the present invention and the photovoltaic power generation system including the same allows the leakage current caused by the ground fault or leakage current to bypass the ground switching unit 1300 instead of flowing to the human body or peripheral electrical installations, thereby fundamentally preventing electric shock or fire caused by leakage current. By means of the configuration described above, in accordance with a device, method, and distribution system for preventing electric shock and fire during current leakage and earth fault according to the present invention, by detecting a leakage current between a power line, which is insulated from the earth and supplies power, and the earth, to limit the detected leakage current to be a dangerous current or less, or to cut off the flow of current in a human body or peripheral installations, it is possible to prevent electric shock and the occurrence of fire due to leakage current. Description of reference signs 100: electrical installation 210, 210-1, 210-2, 210-3, 210-4: fault detector 211: current detection unit 212: unidirectional current unit 213, 213-1, 213-2: open / close switch 220: controller 230: detection / recovery device 231-233: First to third winding 240: isolation transformer 250: alarm generator 260: Alarm release input device 270: circuit breaker 280: surge protector 290: load 300: main transformer 1100: Power supply unit 1300: ground switching unit 1310, 1320, 1330: First to third ground switch 1410, 1420, 1430: First to third power line 1500: circuit breaker 2100: solar panel 2110: Solar cell module 2220-1, 2220-2: First and second voltage drop unit 2400: connector strip 2410, 2411, 412: DC power line 2420: DC circuit breaker 2430: Collection Unit 2500: charging installation PL1: Power receiving / distribution line PL2: Power line NL: Neutral line N, N1, N2: neutral point R1, R2: Single-phase voltage

Claims

1. A device for preventing electric shock and fire, characterized in that it comprises: one or more fault detectors having one end electrically connected to at least one of two or more earth-isolated power lines with a resistance value greater than or equal to a predetermined earth resistance value and a first neutral point having a potential between the voltages of the two or more power lines, and the other end electrically connected to earth, wherein the fault detector detects a leakage current by forming a current path for the leakage current flowing from the two or more power lines or the first neutral point to earth.

2. The device according to claim 1, further characterized in that each of the fault detectors includes a current detection unit that limits the leakage current to a predetermined or lower dangerous current, and detects the leakage current and emits a detection signal.

3. The device according to claim 2, further characterized in that each of the fault detectors additionally includes a unidirectional current unit that limits the path for the leakage current so that the leakage current flows through the current detection unit in one direction.

4. The device according to claim 1, further characterized in that it additionally comprises: a detection / recovery device that is connected in parallel with a load on one side of the power line load, detects an electrical fault in the power line, or detects the electrical fault in order to recover power.

5. The device according to claim 4, further characterized in that the detection / recovery device includes: a second neutral point that is connected to the first neutral point; and two or more windings having one end connected to each of the two or more power lines, and the other end commonly connected to the second neutral point, given that one of the two or more windings includes at least a coupling winding portion magnetically coupled to any of the remaining windings, and at least one of the two or more windings includes the coupling winding portion in which voltages having phases opposite to those of voltages applied to each of the remaining windings are induced with respect to the second neutral point.

6. The device according to claim 5, further characterized in that the power line supplies single-phase power, the detection / recovery device includes first and second windings having one end connected to each of the power lines and the other end commonly connected to the second neutral point, and the first and second windings are magnetically coupled to each other so that voltages having opposite phases to each other are induced with respect to the second neutral point.

7. The device according to claim 5, further characterized in that the power line supplies three-phase power having phases R, S, and T, the sensing / recovery device includes first to third windings having one end connected between phases R, S, and T and the other end commonly connected to the second neutral point, and each of the first to third windings includes the coupling winding portion in which voltages having phases opposite to those of each of the voltages applied to the remaining windings are each induced with respect to the second neutral point.

8. The device according to claim 5, further characterized in that the power line supplies three-phase power having phases R, S, and T, the sensing / recovery device includes first to third windings having one end connected to each of the phases R, S, and T and the other end commonly connected to the second neutral point, and one of the first to third windings includes the coupling winding portion in which the voltages having phases opposite to those of each of the voltages applied to the remaining windings are each induced with respect to the second neutral point.

9. A method for preventing electric shock and fire, characterized in that it comprises: isolating two or more power lines from earth with a resistance value greater than or equal to a predetermined resistance value; detecting a leakage current between at least one of the two or more power lines and a first neutral point having a potential between the voltages of the two or more power lines and earth; and emitting a detection signal in accordance with the detection of the leakage current.

10. The method according to claim 9, further characterized in that it additionally comprises: cutting off a power supply to a power line through which the leakage current flows intertwined with the detection signal; and recovering the cut-off power and supplying the recovered power to a load.

11. A device for preventing electric shock and fire, characterized in that it comprises: a fault detector that is electrically connected to a power supply unit for transmitting AC or DC electricity from the power supply unit to a load installation, and configured to detect whether a leakage current occurs between at least one of two or more power lines insulated from earth with a resistance value greater than or equal to a predetermined earth resistance value and a neutral point having a potential between the voltages of the two or more power lines and earth, wherein the fault detector operates to ground to earth a power line or a neutral point at which the leakage current occurs between the two or more power lines and the neutral point when the leakage current occurs.

12. The device according to claim 11, further characterized in that it additionally comprises: a ground switching unit that is controlled to short-circuit to earth a power line or a neutral point at which leakage current occurs between the two or more power lines and the neutral point according to the detection result of the fault detector to ground the power line or the neutral point.

13. The device according to claim 12, further characterized in that the fault detector includes two or more fault detectors respectively electrically connected between the two or more power lines and earth, and the earth switching unit includes two or more earth switches whose switching on or off is controlled in response to each of the two or more fault detectors.

14. The device according to claim 13, further characterized in that at least one of the two or more ground switches is a normally open (NO) type switch that is turned on when an operating current greater than or equal to a predetermined reference value flows in a corresponding fault detector, and is electrically connected to at least one of a power line and a neutral point other than a power line, to which the corresponding fault detector is connected, between the two or more power lines and the neutral point.

15. The device according to claim 13, further characterized in that at least one of the two ground switches is a normally closed (NO) type switch that is turned off when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector, and is electrically connected in parallel to the corresponding fault detector.

16. The device according to claim 14, further characterized in that the power supply unit is a three-phase AC power supply comprising a phase-R, phase-S, and phase-T, the fault detector comprising first to third fault detectors respectively connected between phase-R, phase-S, and phase-T and earth.The ground switching unit includes first to third ground switches that correspond to each of the first and second fault detectors and are turned on when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector, and the first to third ground switches are installed between a plurality of power lines and earth so that, when leakage current or earth fault occurs in any of the plurality of power lines connected to phase-R, phase-S, and phase-T, the corresponding power line is grounded.

17. The device according to claim 15, further characterized in that the power supply unit is a three-phase AC power supply including phase-R, phase-S, and phase-T; the fault detector includes first to third fault detectors respectively connected between phase-R, phase-S, and phase-T and earth; the earth switching unit includes first to third earth switches corresponding to each of the first to third fault detectors and are turned off when an operating current greater than or equal to a predetermined reference value flows in the corresponding fault detector; and the first to third earth switches are installed between a plurality of power lines and earth such that, when leakage current or earth fault occurs in one or more of the plurality of power lines connected to phase-R, phase-S, and phase-T, the corresponding power line is connected to earth.

18. A distribution system for preventing electric shock and fire, characterized in that it comprises: a power supply unit configured to provide AC or DC electricity to a load facility; two or more power lines electrically connected to the power supply unit and insulated from earth with a resistance value greater than or equal to a predetermined earth resistance value; and the device for preventing electric shock and fire of claim 11.

19. A device for preventing electric shock and fire from a photovoltaic power generation system, the device being characterized in that it comprises: one or more electrically connected fault detectors between at least one of the two or more power lines that are electrically connected to a solar panel in which one or more solar cell modules are arranged to transmit electricity generated from the solar panel to a charging installation and a neutral point having a potential between the voltages of the two or more power lines and earth to detect if a leakage current occurs between at least one of the two or more power lines isolated from earth with a resistance value greater than or equal to a predetermined earth resistance value and earth;and a ground switching unit that is controlled to short-circuit to earth a power line in which leakage current occurs between the two or more power lines according to the detection result of the fault detector to ground the power line.

20. The device according to claim 19, further characterized in that the two or more power lines include first and second DC power lines that transmit DC electricity generated from the solar panel, and the fault detector includes first and second fault detectors having one end electrically connected to the first and second DC power lines, respectively, and forming a current path for a leakage current flowing into the ground to detect the leakage current from the current path.

21. The device according to claim 20, further characterized in that the earth switching unit includes: a first earth switch that is controlled to ground the second DC power line to earth when leakage current flows in the second DC power line according to the detection result of the fault detector; and a second earth switch that is controlled to ground the first DC power line to earth when leakage current flows in the first DC power line according to the detection result of the fault detector.

22. The device according to claim 19 further characterized in that two or more power lines include first and second DC power lines that transmit DC electricity generated from the solar panel, the fault detector includes first and second fault detectors that are electrically connected between the first and second DC power lines and earth, respectively, and in the first and second fault detectors, an operating current flows at a predetermined reference value or higher in a normal state, and when leakage current occurs, the operating current flows in the fault detector connected to a DC power line, through which the leakage current flows, at the predetermined value or lower.

23. The device according to claim 19, further characterized in that the two or more power lines include first and second DC power lines that transmit DC electricity generated from the solar panel, the fault detector is electrically connected between a neutral point having a potential between the voltages of the two or more power lines and earth, and forms a current path for a leakage current flowing into earth to detect the leakage current from the current path, and a power line in which the leakage current occurs is identified from among the two or more power lines according to a direction of leakage current flowing through the fault detector.

24. A photovoltaic power generation system, characterized in that it comprises: a solar panel in which one or more solar cell modules are arranged; two or more power lines that are electrically connected to the solar panel to transmit electricity generated from the solar panel to a load installation and isolated from the earth with a resistance value greater than or equal to a predetermined earth resistance value; and the device for preventing electric shock and fire in accordance with claim 19.

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