Abnormal current detection apparatus and control method thereof

Abstract

The present invention relates to an abnormal current detection device comprising: a semiconductor switch connected to any one of a plurality of circuits connecting a power system and a power device so as to connect the power system and the power device; a gate driver that applies a gate voltage to the semiconductor switch; and a control unit that determines whether or not there is a ground fault current on the basis of a current flowing into the semiconductor switch between the connected power system and the power device, controls the gate driver to disconnect the power device from the power system on the basis of the determination result, and controls the gate driver to disconnect the power device from the power system if the power device is disconnected from the power system. If the current flows into the semiconductor switch, the gate driver is controlled with a preset time as a cycle to re-determine whether a ground fault current exists according to the current flowing into the semiconductor switch, and the gate driver is controlled to re-disconnect the connection state or maintain the connection state on the basis of the re-determination result.

Description

Technical Field

[0001] This invention relates to an abnormal current detection device for detecting abnormal currents such as ground fault current. Background Technology

[0002] In power systems, early detection of ground faults is crucial not only for preventing potential hazards but also for maintaining critical systems online, which is of paramount importance from both an economic and safety perspective. Therefore, ongoing research is underway into technologies for detecting ground faults, leading to the development of various ground fault detectors.

[0003] As a representative ground fault detector, such as Figure 1 As shown, there is a GFDI (Ground Fault Detection Indicator) 50. The GFDI (50) includes a fuse and can be connected to the electrical device 10 connected to the power system 30. For example, if the power system 30 includes renewable energy power generation devices such as solar or geothermal power generation devices, each of the renewable energy power generation devices can be an electrical device 10 connected to the power system, and each renewable energy power generation device is equipped with a GFDI (50) to determine whether a ground fault has occurred.

[0004] On the other hand, the fuse in the GFDI (50) is blown by overcurrent such as leakage current caused by a ground fault, thereby opening the circuit. For example, the GFDI (50) can be configured on the circuit connecting various renewable energy power generation devices to the power system 30. Thus, in the event of a ground fault in the power device 10, such as a renewable energy power generation device, the overcurrent caused by the ground fault causes the fuse in the GFDI (50) to blow, thereby opening the circuit connecting the power device 10 and the power system 30. Therefore, the power device 10 experiencing the ground fault can disconnect from the power system 30 from the ground fault.

[0005] However, as mentioned above, the GFDI (50) can detect a ground fault when a fuse installed in the device blows, causing an open circuit. However, the blowing of the fuse is an irreversible change, and even if the ground fault of the power device 10 is repaired, the circuit remains open until the blown fuse is replaced, meaning there is a problem that the power device 10 remains disconnected from the power system 30.

[0006] Thus, regardless of whether the ground fault has been repaired, the electrical device 10 remains disconnected until the fuse is replaced. Therefore, it is difficult for operators to know whether the electrical device 10 connected to the GFDI (50) is in a state where the ground fault has been repaired, which is a problem. Furthermore, since the GFDI (50) detects a ground fault by the blowing of a fuse, there is a problem that the blown fuse, i.e., the GFDI (50), needs to be replaced in order to reconnect the disconnected electrical device 10 to the power system 30. That is, even if the ground fault has been repaired, the electrical device 10 remains disconnected until the GFDI (50) is replaced, thus unnecessarily prolonging the time the electrical device 10 remains disconnected until the GFDI (50) is replaced.

[0007] On the other hand, if the ground fault of the power installation 10 is repaired, the ground fault current may not occur when the circuit is reconnected by replacing the GFDI (50). However, if the power installation is reconnected to the power system by replacing the GFDI while the ground fault is not repaired, there is a problem that workers may be exposed to the ground fault current, which could lead to electric shock.

[0008] Furthermore, as described above, since the GFDI (50) utilizes the characteristic that an overcurrent causes a fuse to blow, there is a problem that a ground fault can only be detected when the overcurrent generated by the ground fault is greater than a predetermined value. That is, if the overcurrent generated by the ground fault is less than the minimum current required to blow the fuse (e.g., in a circuit with a weak current), it is difficult to detect. Alternatively, if the current that normally flows between the power device 10 and the power system 30 is greater than the fuse blowing current, it is difficult to use the GFDI (50) to detect the ground fault. Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The purpose of this invention is to solve the above-mentioned problems and other problems. The purpose is to provide an abnormal current detection device and a control method for the device. When the abnormal current detection device detects an abnormal current caused by an abnormal state such as a ground fault or short circuit, it can determine whether to repair the detected abnormal state, so that the operator can easily confirm whether the abnormal state has been repaired.

[0011] Furthermore, the present invention aims to provide an abnormal current detection device and a control method for the device, wherein the abnormal current detection device can prevent the power device from being unnecessarily disconnected even if a ground fault has been detected and repaired.

[0012] Furthermore, the present invention aims to provide an abnormal current detection device and a control method for the device, wherein the abnormal current detection device can easily detect whether a ground fault has occurred when the ground fault current is less than the fuse breaking current in a weak current loop or when the current normally flowing between the power device 10 and the power system 30 is greater than the fuse breaking current.

[0013] Technical solutions to the problem

[0014] To achieve the above or other objectives, according to one aspect of the present invention, an abnormal current detection device according to an embodiment of the present invention includes: a semiconductor switch connected to any one of a plurality of circuits connecting a power system and a power device, thereby connecting the power system and the power device; a gate driver applying a gate voltage to the semiconductor switch; and a control unit that, between the connected power system and the power device, determines whether a ground fault current exists based on the current flowing into the semiconductor switch, controls the gate driver based on the determination result to disconnect the power device from the power system, and if the power device is disconnected from the power system, controls the gate driver to connect the power device and the power system at a preset constant time period, thereby re-determining whether a ground fault current exists based on the current flowing into the semiconductor switch, and controlling the gate driver based on the re-determination result to again disconnect the power device from the power system or maintain the state of connection between the power device and the power system.

[0015] In one embodiment, any one of the plurality of circuits is a neutral line connecting the power device to the power system, the neutral line being connected to ground, the source terminal of the semiconductor switch being connected to the neutral line, and the drain terminal of the semiconductor switch being connected to the ground.

[0016] In one embodiment, if the power device is disconnected from the power system, the control unit applies a limited-level gate voltage to the gate terminal of the semiconductor switch at a constant time period to temporarily connect the source terminal and the drain terminal, thereby re-determining whether there is a ground fault current. If the re-determination result is that there is no ground fault current, the limited-level gate voltage is restored.

[0017] In one embodiment, the restricted gate voltage is a voltage above a threshold voltage that enables electrical connection between the source and drain terminals in the semiconductor switch, and is a voltage lower than the level of the recovered gate voltage.

[0018] In one embodiment, a management system communicatively connected to the abnormal current detection device transmits a reference current to the abnormal current detection device based on ground fault detection information, including the detection result of the ground fault current and information associated with the power device that detected the ground fault current. The reference current is used by the abnormal current detection device to further determine whether the ground fault current exists. The abnormal current detection device further determines whether the ground fault current exists based on a comparison between the detection result of the current flowing into the semiconductor switch from the power device connected at the constant time period and the power system and the reference current.

[0019] In one embodiment, the control unit compares the result of analyzing the characteristics of the current flowing into the semiconductor switch with the abnormal current characteristics according to a preset abnormal current profile. Based on the comparison result, and based on whether the analyzed current characteristics match the judgment result of the abnormal current characteristics, it determines or further determines whether the ground fault current exists. The abnormal current profile includes at least one of the current magnitude change over time, the average current magnitude, and the difference between the maximum and minimum current values, and is provided by the management system.

[0020] Furthermore, according to an embodiment of the present invention, the abnormal current detection device includes a semiconductor switch connected to any one of a plurality of circuits connecting a power system and a power device. The control method includes: controlling the semiconductor switch to connect the power device and the power system; detecting the current flowing between the connected power device and the power system, and determining, based on a preset ground fault detection current, whether a ground fault current exists; controlling the semiconductor switch to disconnect the power device from the power system based on the result of the first determination; checking whether a preset constant time has elapsed; if the result of the check is that the constant time has elapsed, controlling the semiconductor switch to reconnect the power device and the power system; detecting the current flowing between the reconnected power device and the power system, and determining, based on a preset reference current, whether a ground fault current exists a second time; and, based on the result of the second determination, either performing the step of checking whether the constant time has elapsed again up to the second determination step, or maintaining the connection between the power device and the power system.

[0021] In one embodiment, any one of the plurality of circuits is a neutral line connecting the power device and the power system, the neutral line being connected to ground, the source terminal of the semiconductor switch being connected to the neutral line, the drain terminal of the semiconductor switch being connected to the ground, the step of controlling the semiconductor switch to connect the power device and the power system is the step of applying a first gate voltage above a preset threshold voltage to the gate terminal of the semiconductor switch to electrically connect the source terminal and the drain terminal of the semiconductor switch, and the step of controlling the semiconductor switch to reconnect the power device and the power system is the step of applying a second gate voltage above the threshold voltage and below the first gate voltage to the gate terminal of the semiconductor switch.

[0022] Furthermore, the abnormal current detection device of this invention includes: a current detection unit disposed in any one of a plurality of circuits connecting a power system and a power device, connecting the power system and the power device, detecting the presence of an abnormal current based on preset detection information, and disconnecting the power device from the power system based on the abnormal current detection result; a semiconductor switch connected to the current detection unit to form a bypass circuit bypassing the current detection unit, the semiconductor switch including a gate driver, which applies a gate voltage to control the first terminal and the second terminal, respectively connected to the first and second poles of the current detection unit, to electrically connect or disconnect the first terminal from the second terminal; and a control unit that, if the power device is disconnected from the power system due to whether the current detection unit detects an abnormal current, electrically connects the first terminal to the second terminal, determines the presence of an abnormal current based on the current flowing through the connected first terminal and the second terminal in the bypass circuit, and controls the semiconductor switch based on the determination result to disconnect the bypass circuit or maintain the connection between the power system and the power device through the bypass circuit.

[0023] In one embodiment, the current detection unit is a GFDI (Ground Fault Detection Indicator), which includes a fuse that blows when an overcurrent exceeding a preset fusing current flows in. The fuse is connected between the neutral line and ground in a plurality of circuits connecting the power system and the power device.

[0024] In one embodiment, the first terminal of the fuse is connected to the neutral line, the second terminal of the fuse is connected to the ground, the first terminal of the semiconductor switch is connected between the first terminal of the fuse and the neutral line, and the second terminal of the semiconductor switch is connected between the second terminal of the fuse and the ground.

[0025] In one embodiment, the control unit is linked to the melting of the fuse to activate the inactive semiconductor switch. When the melted fuse is replaced and the first and second terminals of the fuse are electrically connected, the control unit switches the activated semiconductor switch to an inactive state.

[0026] In one embodiment, the control unit forms a first bypass circuit by controlling the semiconductor switch to apply a first gate voltage exceeding a preset threshold voltage. The first bypass circuit is used to determine whether the abnormal current exists. If the determination result is that there is no abnormal current, the control unit controls the semiconductor switch to apply a second gate voltage greater than the first gate voltage to form a second bypass circuit for maintaining the connection between the power system and the power device.

[0027] Furthermore, the abnormal current detection device of this embodiment includes: a current detection unit that connects the neutral line to ground in a plurality of circuits connecting a power system and a power device, detects an abnormal current flowing in the neutral line, and disconnects the power device from the power system if an abnormal current is detected; a solid state circuit breaker having a semiconductor switch and a control unit, the semiconductor switch being connected to the current detection unit to receive an abnormal current detection result provided by the current detection unit, and if the current detection unit detects an abnormal current and disconnects the power device from the power system, a bypass circuit is formed that bypasses the current detection unit and connects the neutral line to the ground; the control unit determines whether there is an abnormal current flowing in the neutral line based on the current flowing in the bypass circuit, and controls the semiconductor switch based on the determination result to disconnect the bypass circuit or maintain the connection between the neutral line and the ground through the bypass circuit.

[0028] In one embodiment, the current detection unit is a GFDI (Ground Fault Detection Indicator). The GFDI includes a fuse that blows when an abnormal current exceeding a preset fusing current flows in. Based on the fuse blowing, the GFDI transmits abnormal current detection information to the management system and the semiconductor circuit breaker. After receiving the abnormal current detection information, the semiconductor circuit breaker switches from an inactive state to an active state.

[0029] In one embodiment, if the neutral line is connected to the ground via the fuse due to the replacement of the blown fuse, the GFDI transmits an inactive signal to the semiconductor circuit breaker. If the inactive signal is received, the semiconductor circuit breaker switches from an active state to an inactive state and transmits information to the management system indicating that the power device is properly connected.

[0030] Invention Effects

[0031] According to at least one embodiment of the present invention, the present invention has the following advantages: it can automatically detect whether a power device with a detected ground fault has been repaired, and display whether it is in a normal connection state according to the detection result, so that the operator can easily identify the power device with the ground fault repaired and the power device with the ground fault not repaired, thereby preventing the operation of the power device with the ground fault not repaired, thereby preventing the safety accidents of the operator.

[0032] Furthermore, the present invention has the following effect: when a ground fault is repaired, the time during which the power device is unnecessarily disconnected can be reduced by closing the circuit between the power device and the power system.

[0033] Furthermore, the present invention has the following advantages: by utilizing a semiconductor power circuit breaker to detect ground faults, the ground fault detection current can be freely set. Therefore, even in cases where a weak current flows that is difficult to detect with existing fuses, or where a current exceeding the fuse's breaking current flows, it is easy to detect whether a ground fault has occurred.

[0034] Furthermore, according to at least one embodiment of the present invention, the present invention has the following advantages: automatically detecting whether an electrical device with an abnormal state has been repaired, and displaying whether there is an abnormal current flow from the electrical device with the detected abnormal state based on the detection result, thereby enabling operators to easily identify electrical devices with abnormal states and those without abnormal states, thereby preventing related repair work on electrical devices with abnormal states that have not been repaired, and thus preventing safety accidents of operators.

[0035] Furthermore, the present invention has the following effect: even if the abnormal condition has been repaired and the GFDI fuse is in a blown state, the power device can be connected to the power system through the bypass circuit, thereby shortening the time when the repaired power device is unnecessarily disconnected from the power system. Attached Figure Description

[0036] Figure 1 This is a block diagram showing the structure of a GFDI connecting an electrical device to a power system.

[0037] Figure 2 This is a block diagram illustrating an abnormal current detection device according to an embodiment of the present invention that uses a semiconductor circuit breaker to detect grounding faults.

[0038] Figure 3 This is a flowchart illustrating the operation process of the abnormal current detection device of the present invention in detecting ground faults and determining whether a ground fault exists.

[0039] Figure 4 This is a flowchart illustrating the operation process of the management system based on ground fault detection when the reference current is set according to the control of the management system.

[0040] Figure 5 This is a flowchart illustrating the operation process of the abnormal current detection device according to the abnormal current detection result to detect grounding faults in an embodiment of the present invention.

[0041] Figure 6 An example of an abnormal current detection device according to an embodiment of the present invention is shown, wherein in the case of a plurality of electrical devices connected to a power system, the device is respectively configured between the plurality of electrical devices and the plurality of power systems.

[0042] Figure 7 This is a block diagram illustrating the structure of an abnormal current detection device with a semiconductor circuit breaker according to an embodiment of the present invention.

[0043] Figure 8 This is a flowchart illustrating the operation process of the abnormal current detection device of the present invention in detecting ground faults and determining whether a ground fault exists.

[0044] Figure 9 It is shown in more detail in the above. Figure 2 The flowchart shows the process of determining whether an abnormal current is detected during the operation.

[0045] Figure 10 An example of an abnormal current detection device according to an embodiment of the present invention is shown, which is connected to a plurality of electrical devices and configured between the plurality of electrical devices and the respective power systems. Detailed Implementation

[0046] It should be noted that the technical terminology used in this specification is for illustrative purposes only and is not intended to limit the invention. Furthermore, unless explicitly stated in the context, singular expressions used in this specification include plural expressions. Terms such as "constituting" or "comprising" should not be construed as necessarily including all the various constituent elements or steps described in the specification, but should be interpreted as excluding some constituent elements or steps, or including additional constituent elements or steps.

[0047] In addition, when describing the technology disclosed in this specification, if it is determined that a detailed description of the relevant known technology may obscure the technical essence disclosed in this specification, its detailed description shall be omitted.

[0048] First, let me explain the essence of this invention. In order to solve the problem existing in the GFDI, that is, when a ground fault is detected, the circuit remains open regardless of whether the detected ground fault has been repaired, which makes it impossible for operators to know whether the power device connected to the GFDI to be worked is in a state of ground fault. The abnormal current detection device of this invention adopts a semiconductor circuit breaker (SSCB) using a semiconductor switch. The semiconductor switch can disconnect the power device from the power system at high speed when a ground fault is detected, thereby detecting whether there is a ground fault and whether the power device is in a normal connection state.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0050] Figure 2 This is a block diagram illustrating an abnormal current detection device according to an embodiment of the present invention that uses a semiconductor circuit breaker to detect grounding faults.

[0051] Reference Figure 2 First, an electrical device 10 can be connected to the power system 30. The electrical device 10 can be a renewable energy power generation device such as a solar power generation device. In this case, the DC power generated by the renewable energy power generation device can be converted into AC power by a converter 20 and then supplied to the power system 30. The power system 30 can be a system that includes a storage device for storing the generated electrical energy or a grid, etc., that supplies power to multiple demanders.

[0052] Thus, when the power device 10 is connected to the power system 30, the abnormal current detection device 100 of this embodiment can be connected between the power device 10 and the power system 30. Wherein, when the power device 10 is connected to the power system 30... Figure 2 In the case of a power generation device as shown, the power device 10 can be configured as a circuit consisting of a P (Positive) phase circuit and an N (Neutral) phase circuit. The P (Positive) phase circuit is the circuit that inputs the electrical energy generated by the power device 10 into the power system 30, and the N (Neutral) phase circuit is the circuit that returns the current. The P line can be named the live line or hot line, and the N line can be named the neutral line.

[0053] In addition, such as Figure 2 As shown, in the case where the power system 30 has a converter 20, the abnormal current detection device 100 of this embodiment of the invention can be disposed between the power device 10 and the converter 20. In this case, the converter 20 and the power device 10 can be connected by the P line and the N line.

[0054] On the other hand, an abnormal current detection device 100 according to an embodiment of the present invention will be described. The abnormal current detection device 100 may include a semiconductor switch 110. In addition, the abnormal current detection device 100 may be connected to a management system 200, which may be configured to control a display unit 300 connected by wires or wirelessly.

[0055] To explain the configuration of the abnormal current detection device 100 in detail, firstly, the abnormal current detection device 100 can be connected to the N-line, which serves as the neutral line, in the circuit constituting the line connecting the power device 10 and the power system 30. In this case, the source terminal of each terminal of the semiconductor switch 110 can be connected to the N-line, and the drain terminal of the semiconductor switch 110 can be grounded. Thus, by grounding the neutral line via the semiconductor switch 50, the neutral line, i.e., the N-line, can become a grounding line. Therefore, the return current flowing through the neutral line can be grounded via the semiconductor switch 110. Therefore, in the event of a ground fault in the power device 10, abnormal currents such as ground fault current, leakage current, or short-circuit current caused by the ground fault can be grounded via the semiconductor switch 110. That is, in the event of a ground fault, the ground fault current, leakage current, or short-circuit current superimposed may increase the magnitude of the current flowing into the semiconductor switch 110. Therefore, the occurrence of the ground fault current, leakage current, or short circuit current can be detected based on the magnitude of the current flowing into the semiconductor switch 110.

[0056] On the other hand, the semiconductor switch 100 has a source terminal and a drain terminal, and may include a gate terminal that electrically connects the source terminal and the drain terminal. The semiconductor switch 110 may be configured to electrically connect the source terminal and the drain terminal when the voltage applied to the gate terminal reaches or exceeds a preset threshold voltage. The semiconductor switch 110 can use the voltage applied to the gate terminal, i.e., the gate voltage, to detect whether the ground fault current has occurred, and can disconnect the power device 10 from the power system 30 from which the ground fault current is occurring.

[0057] Therefore, the abnormal current detection device 100 of this embodiment may include a gate driver 111 that applies the gate voltage to the gate terminal. Additionally, it may include a control unit 130 that controls the gate voltage applied by the gate driver 111 to the gate terminal.

[0058] More specifically, the control unit 130 can detect the magnitude of the return current flowing through the semiconductor switch 110 to ground and determine whether the detected magnitude is above a preset ground fault detection current. Furthermore, if the detected current is below the ground fault detection current, the gate driver 111 can be controlled to normally connect the source and drain terminals. In this case, the control unit 130 can control the gate driver 111 to apply a gate voltage above a preset threshold voltage to the gate terminal, thereby electrically connecting the source and drain terminals, allowing the return current to flow to ground. This enables the power device 10 to be connected to the power system 30.

[0059] Conversely, if the magnitude of the return current flowing through the semiconductor switch 110 to ground is greater than a preset ground fault detection current, the control unit 130 can determine that a ground fault has occurred and control the gate driver 111 to disconnect the connection between the source and drain terminals. In this case, the control unit 130 can disconnect the electrical connection between the source and drain terminals by controlling the gate driver 111 to apply a gate voltage lower than a preset threshold voltage to the gate terminal.

[0060] Therefore, the neutral line can be grounded, disconnecting the connection between the power device 10 and the power system 30. That is, the power device 10 can be disconnected from the power system 30. In addition, if the power device 10 is disconnected from the power system 30, the abnormal current detection device 100 of this embodiment can notify the management system 200 that a ground fault has occurred between the power device 10 and the power system 30.

[0061] Thus, when the connection between the source and drain terminals is disconnected based on the detection result of the current flowing to the ground wire, the control unit 130 of the abnormal current detection device 100 can control the gate driver 111 at a preset time period to apply a voltage above the threshold voltage. In this case, the source and drain terminals can be turned on again, and the current flowing in the neutral line can flow to ground again via the semiconductor switch 110.

[0062] Thus, when the source terminal and drain terminal are connected, the control unit 130 can detect the current flowing to the grounding wire again. Furthermore, based on whether the current flowing to the grounding wire is above a preset ground fault detection current, it can again detect whether the power device 10 is in a ground fault state.

[0063] On the other hand, the connection between the source terminal and the drain terminal can be a temporary connection for re-detecting whether the power device 10 is in a ground fault state. That is, the temporary connection is made when the current flowing through the semiconductor switch 110 to ground is not less than the ground fault detection current. The gate voltage applied to the gate terminal to connect the source terminal and the drain terminal for the temporary connection can be a different voltage than that applied to the gate terminal under normal circumstances, i.e., when it has been confirmed that the current flowing through the semiconductor switch 110 to ground is less than the ground fault detection current.

[0064] As an example, the control unit 130 can also control the maximum amount of current that can be conducted between the source and drain terminals by controlling the magnitude of the gate voltage. That is, the smaller the gate voltage (above the threshold voltage), the smaller the maximum value of the current that can be output through the semiconductor switch 110, i.e., the maximum value of the current that can be output through the source and drain terminals. Conversely, the larger the gate voltage (above the threshold voltage), the larger the maximum value of the current that can be output through the semiconductor switch 110, i.e., the maximum value of the current that can be output through the source and drain terminals. In addition, since the maximum value of the output current is limited, the magnitude of the current flowing into the semiconductor switch 110 can also be limited.

[0065] Therefore, the control unit 130 can limit the magnitude of the gate voltage applied to the gate terminal during the temporary connection, making it smaller than the gate voltage applied to the gate terminal to connect the power device 10 to the power system 30 under normal conditions, i.e., under normal conditions when no ground fault is detected.

[0066] Thus, when the source terminal and drain terminal are temporarily connected, the abnormal current detection device 100 of this embodiment limits the magnitude of the current flowing into and out of the semiconductor switch 110 by limiting the gate voltage level, thereby minimizing the magnitude of the current turned on to the semiconductor switch 110 for detecting ground faults, and thereby preventing safety accidents and burnout of the abnormal current detection device 100.

[0067] Thus, when the ground fault current causes the gate voltage applied to the gate terminal to be controlled to disconnect the connection between the source terminal and the drain terminal, the control unit 130 of the abnormal current detection device 100 of this embodiment can arbitrarily apply a gate voltage above a threshold voltage to the gate terminal to confirm whether the ground fault state continues. Furthermore, it can determine again whether the power device 10 is experiencing a ground fault based on the current flowing into the neutral line when a gate voltage above the threshold voltage is applied.

[0068] On the other hand, if a ground fault is detected, the control unit 130 can notify the management system 200 of the detected status of the power device 10. Therefore, the abnormal current detection device 100 of this embodiment may further include a communication unit 140, which is controlled by the control unit 130 and performs a communication connection with the management system 200 wirelessly or via a wired connection.

[0069] The management system 200 can be a system for managing the ground fault determination results received from the abnormal current detection device 100. For example, the management system 200 can be a PMS (Power Management System). The management system 200 can detect that a ground fault has occurred between the power device 10 and the power system 30 based on the ground fault detection information received from the abnormal current detection device 100 of this embodiment of the invention.

[0070] Furthermore, the abnormal current detection device 100 of this embodiment can receive the ground fault determination result and detect whether a ground fault exists between the power device 10 and the power system 30. Additionally, the display unit 300 can be controlled to display the received ground fault determination result, so that operators can easily identify whether the ground fault exists.

[0071] The display unit 300 may include at least one of a display unit and an audio output unit for displaying visual or auditory information indicating whether a ground fault exists between the power device 10 and the power system 30, and may be configured to communicate with the management system 200. Furthermore, the display unit 300 may be located in an additional device separate from the management system 200. For example, the display unit 300 may be a mobile terminal such as a smartphone, PDA, or tablet PC carried by the operator. Therefore, the operator can easily confirm whether a ground fault exists between the power device 10 and the power system 300 through the display unit 300.

[0072] On the other hand, when the source and drain terminals are temporarily connected, if the current flowing into the semiconductor switch 110 from the ground wire is less than a preset current value, the control unit 130 can determine that the grounding fault of the power device 10 has been repaired, and the power device 10 and the power system 30 are in a state where they can be normally connected. Therefore, the control unit 130 can control the gate driver 111 to apply an unrestricted gate voltage. As a result, the maximum output current between the source and drain terminals can be restored to the normal range. Therefore, the source and drain terminals are normally conducting, and with the neutral wire grounded, the power device 10 can be normally connected to the power system 30.

[0073] Figure 3 This is a flowchart illustrating the operation process of the abnormal current detection device of the present invention in detecting ground faults and determining whether a ground fault exists.

[0074] Reference Figure 3 When the power is on, the control unit 130 of the abnormal current detection device 100 of this embodiment first sets the magnitude of the ground fault detection current according to the management system 200 or pre-stored data (S300). Additionally, the control unit 130 can control the gate driver 111 to apply a normal-level gate voltage (S302). The normal-level gate voltage refers to the gate voltage applied when the normally driven power device 10 is connected to the power system 30, and can be a voltage of a magnitude greater than or equal to a threshold voltage.

[0075] In step S302, if a normal gate voltage is applied, the control unit 130 can detect the current flowing into the semiconductor switch 110 connected between the neutral line and ground, i.e., the magnitude of the current applied from the neutral line to ground (S304). Additionally, it can be determined whether the detected return current is greater than or equal to the ground fault detection current set in step S300 (S306).

[0076] On the other hand, the control unit 130 of the abnormal current detection device 100 in this embodiment of the invention determines whether there is a ground fault by comparing the detected return current with a pre-stored value, namely, a ground fault detection current. Therefore, regardless of the fuse blowing current, a ground fault can be determined by comparing the current value based on the received or pre-stored ground fault detection current information with the detected return current value.

[0077] Therefore, unlike existing GFDIs that are limited to detecting ground faults based on fuse blowing current, the abnormal current detection device 100 of this embodiment can detect ground faults based on a current smaller than the fuse blowing current, or it can freely detect ground faults even in high-capacity current circuits where the return current flowing normally when the power device 10 is connected to the power system 30 is greater than the fuse blowing current. In other words, by dynamically setting the ground fault detection current that can determine whether a ground fault is present, it has the advantage of making it easier to detect ground faults.

[0078] On the other hand, if the determination result of step S306 is that the detected return current is less than the preset ground fault detection current, then the control unit 130 can determine that no ground fault has occurred in the power unit 10. Therefore, the control unit 130 can execute step S304 again, detect the return current again, and compare the detected return current with the preset ground fault detection current in step S306.

[0079] However, if the detected return current in step S306 is above a preset ground fault detection current, the control unit 130 can determine that a ground fault has occurred in the power device 10. Therefore, the control unit 130 can control the gate driver 111 to apply a gate voltage less than a preset threshold voltage to the gate terminal of the semiconductor switch 110. This disconnects the electrical connection between the source and drain terminals of the semiconductor switch 110, causing the connection between the neutral line and ground to be broken, which may disconnect the electrical connection between the power device 10 and the power system 30 (S308).

[0080] If the electrical connection between the power device 10 and the power system 30 is disconnected during step S308, the control unit 130 can control the communication unit 140 to transmit ground fault detection information indicating a ground fault to the management system 200 (S310). In this case, the information of the power device associated with the currently detected ground fault, i.e., the information of the power device 10 connected to the power system 30 via the neutral line connected to the abnormal current detection device 100 of this embodiment, can be transmitted to the management system 200.

[0081] Therefore, the management system 200 can identify the electrical device 10 associated with the detected ground fault and control the display unit 300 to distinguish the identified electrical device 10 from other fault-free electrical devices.

[0082] On the other hand, if the electrical connection between the source and drain terminals of the semiconductor switch 110 is broken in step S308, the control unit 130 can check whether a constant time has elapsed (S312). Furthermore, if the constant time has elapsed, the gate driver 111 can be controlled to apply a gate voltage greater than a threshold voltage to the gate terminal of the semiconductor switch 110, thereby temporarily connecting the source and drain terminals (S314).

[0083] In this case, for the temporary connection between the source and drain terminals, the control unit 130 can control the gate driver 111 to apply a limited-level gate voltage to the gate terminal.

[0084] The restricted gate voltage can be a gate voltage lower than the normal gate voltage level. That is, although both the restricted gate voltage and the normal gate voltage have a level above a threshold voltage, the restricted gate voltage can be a voltage with a lower gate voltage level than the normal gate voltage. Therefore, as the gate voltage is restricted, the magnitude of the current output from the neutral line to ground may also be restricted.

[0085] On the other hand, in step S314, as a restricted gate voltage is applied to the gate terminal, the source and drain terminals can be temporarily connected. Therefore, the neutral line can be temporarily connected to ground, allowing the neutral line current to flow to ground. Furthermore, the control unit 130 can detect the current flowing through the source and drain terminals based on the restricted gate voltage, i.e., based on the magnitude of the return current (hereinafter, restricted return current) of the restricted gate voltage (S316).

[0086] Based on the inspection result of step S316, the control unit 130 can determine whether a ground fault current is still detected from the power device 10 based on the restricted return current. More specifically, in step S316, the control unit 130 can determine whether the power device 10 is in a state where a ground fault current is detected based on the comparison result between the restricted return current and a preset reference current (S318).

[0087] The reference current can be a current of a different magnitude than the ground fault detection current. For example, the restricted return current can be a state where current flow is restricted due to a restricted gate voltage. Therefore, the reference current can be a current smaller than the ground fault detection current.

[0088] In step S318, if the restricted return current is compared with the preset reference current and the restricted return current is greater than the reference current, the control unit 130 can determine that it is still in the state of detecting a ground fault current from the power device 10.

[0089] Therefore, the control unit 130 can disconnect the electrical connection between the source terminal and the drain terminal by controlling the gate terminal to apply a gate voltage less than the threshold voltage (S320). In addition, step S312 is executed again to determine whether a constant time has elapsed. If the constant time has elapsed, the process from step S314 to step S318 can be repeated to detect whether the restricted return current is above the reference current.

[0090] Conversely, if the determination result of step S318 is that the restricted return current is less than the reference current, the control unit 130 can determine that the power device 10 is in a state where ground fault current is no longer detected due to repairs, etc. Therefore, the control unit 130 can transmit to the management system 200 that the power device 10 is in a normally connected state through the control communication unit 140 (S322).

[0091] Furthermore, by executing step S302, the gate driver 111 can be controlled to apply a normal gate voltage to the gate terminal. This allows the source and drain terminals to be connected in a normal state with the output current restored, rather than a temporary connection where the output current is limited. Additionally, the control unit 130 can repeat the process following step S304.

[0092] On the other hand, the management system 200 can initialize the ground fault occurrence information of the power devices associated with the ground fault based on the received notification of normal connection of the power devices. Therefore, the operator can confirm through the display unit 300 that the power device 10 in which the ground fault current was detected has been repaired.

[0093] On the other hand, the above description illustrates that the abnormal current detection device 100 of the present invention, in order to detect whether the power device 10 is in a state where a ground fault current is still flowing, applies a gate voltage with a limited voltage level to the gate terminal when the source terminal and drain terminal are temporarily connected. However, unlike this, a normal level gate voltage may also be applied.

[0094] In this case, the reference voltage described in step S318 can be a voltage having the same level as the ground fault detection current described in step S300. Furthermore, since the source and drain terminals, which are temporarily connected to detect whether a ground fault current is still flowing in the power unit 10, are turned on with a normal gate voltage, if the determination result of step S318 is that no ground fault current is detected, the return current can be detected while maintaining the applied gate voltage as is. That is, step S302, which restores the gate voltage to its normal state, can be omitted, and the steps after step S304 can be executed directly.

[0095] On the other hand, the above description illustrates that the abnormal current detection device 100 of this embodiment determines whether a ground fault current is detected in the power device 10 based on a preset reference voltage. However, the reference voltage can also be set by the management system 200 under the control of the management system 200. In this case, if the ground fault detection information is received, the management system 200 can identify the power device 10 associated with the detected ground fault, and in response to the ground fault detection information, transmit the reference current corresponding to the identified power device 10 to the abnormal current detection device 100.

[0096] Figure 4 This is a flowchart illustrating the operation process of the management system based on ground fault detection when the reference current is set according to the control of the management system 200.

[0097] Reference Figure 4 When the abnormal current detection device 100 detects a ground fault current, the management system 200 can receive information about the power device associated with the ground fault current detected by the abnormal current detection device 100, i.e., the power device 10 connected to the abnormal current detection device 100, as ground fault detection information (S400).

[0098] Thus, the management system 200 can update the status of the received power device to a ground fault occurrence status, and at the same time control the display unit 300 to display the received power device differently from other power devices that have not received ground fault detection information (S402).

[0099] As described above, the display unit 300 can be a device such as a mobile terminal for the operator to access information. Therefore, the operator can distinguish between electrical devices 10 that have detected ground faults and those that have not, and perform work accordingly. This helps prevent safety accidents that may occur due to ground fault current.

[0100] On the other hand, the management system 200 can estimate the approximate magnitude of the possible ground fault current based on the information of the power device 10 based on the received ground fault detection information (S404). For example, the magnitude of the ground fault current can be estimated based on at least one of the following: the power supply of the power device 10 experiencing the ground fault, the line voltage, the power factor and converter ratio or wiring method, and the resistance of the neutral point. In this case, the approximate magnitude of the ground fault current can also be estimated to be within a certain range.

[0101] If an approximate ground fault current magnitude is estimated in step S404, the management system 200 can determine a reference current based on the estimated ground fault current magnitude (S408). In step S408, the management system can determine the reference current based on the estimated ground fault current magnitude and the magnitude of the restricted return current through a gate voltage based on a restricted level.

[0102] For example, the management system 200 can determine the level of the gate voltage to be limited based on the estimated magnitude of the ground fault current. That is, if the estimated magnitude of the ground fault current is within a predetermined range, the gate voltage level can be limited to a reference limit level. However, if the ground fault current exceeds the predetermined range, the current flowing into the semiconductor switch 110 through the temporary connection can be limited to a smaller level by limiting the gate voltage level to a level lower than the reference limit level.

[0103] On the other hand, if the gate voltage level to be limited is determined in this way, the management system 200 can determine the magnitude of the reference current for re-detecting whether a ground fault current has occurred based on the limited gate voltage level. In this case, the lower the gate voltage level, the smaller the current that can flow through the semiconductor switch 110, and therefore the lower the gate voltage level, the smaller the magnitude of the reference current used for re-detecting whether a ground fault current has occurred.

[0104] If the levels of the reference current and the gate voltage to be limited are determined in step S406, the management system 200 can transmit the determined reference current and the gate voltage level to be limited as a response to the transmission of ground fault detection information to the abnormal current detection device 100 (S408). Thus, the abnormal current detection device 100 can receive the determined reference current and the gate voltage level to be limited as a response to the transmission of abnormal current detection information to the management system 200, and based on the received information, in the... Figure 3 After step S312, check whether a ground fault current occurs.

[0105] On the other hand, if the information of the reference current and the gate voltage to be limited is transmitted to the abnormal current detection device 100, the control unit 130 can detect whether it receives a power device normal connection prompt message from the abnormal current detection device 100 (S410).

[0106] In this case, in the Figure 3 In the process following step S312, if the result of detecting whether a ground fault current has occurred again from the power device 10 is that no ground fault current has been detected, then the abnormal current detection device 100 can... Figure 3 In step S322, a notification of normal connection of the power device is sent to the management system 200. Therefore, the check results in step S410 can confirm that a notification of normal connection of the power device has been received from the abnormal current detection device 100.

[0107] Therefore, in step S300, the management system 200 can update the status information of the power unit 10 where the ground fault occurred based on the ground fault detection information (S412). Thus, the display unit 300 carried by the operator or others can display that no ground fault current was detected from the power unit 10. Therefore, the operator can confirm that the ground fault or other issues with the power unit 10 have been resolved.

[0108] On the other hand, the above description states that the reference current is controlled by the management system 200. However, not only the reference current, but also the ground fault detection current can be set by the management system 200.

[0109] As an example, if the management system 200 establishes a communication connection with the abnormal current detection device 100, it can receive information from the power device 10 connected to the abnormal current detection device 100, and can transmit information about the ground fault detection current that matches the received power device 10 to the abnormal current detection device 100. Therefore, the abnormal current detection device 100 can determine whether a ground fault current has occurred in the connected power device 10 based on the ground fault detection current received from the management system 200.

[0110] Thus, since the management system 200 can control not only the reference current but also the ground fault detection current, it can set at least one of the ground fault detection current and the reference current differently for each power device 10 connected to the abnormal current detection device 100. For example, the management system 200 can set the ground fault detection current and the reference current for power devices that have experienced a preset number of ground faults, based on the ground fault occurrence history of the connected power devices 10, to more sensitively determine whether a ground fault has occurred. In this case, the management system 200 can more sensitively detect whether a ground fault current has occurred by setting the ground fault detection current and the reference current lower than those of other power devices (e.g., other power devices of the same type).

[0111] Alternatively, the management system 200 can set the ground fault detection current and reference current to be less sensitive to ground fault detection for electrical installations located in spaces susceptible to noise or other disturbances. In this case, the management system 200 can make the detection of whether a ground fault current has occurred less sensitive by setting the ground fault detection current and reference current higher than those for other electrical installations (e.g., other electrical installations of the same type).

[0112] On the other hand, the above description illustrates an example where a ground fault current is determined solely based on whether the magnitude of the return current is equal to a preset ground fault detection current. However, unlike this, even if the detected return current is less than the ground fault detection current, if the abnormal current condition is met based on the analysis results of the measured current, the control unit 130 can also control the gate driver 111 to disconnect the power device 10 from the power system 30. Alternatively, if the detected return current is a temporary overcurrent such as noise, the control unit 130 can also control the gate driver 111 to prevent the power device 10 from being disconnected from the power system 30 based on the fact that the measured return current does not meet the abnormal current condition. That is, the control unit 130 can determine whether an abnormal current has occurred based on the analysis results of the characteristics of the measured return current and whether the current characteristics meet the preset abnormal current condition, thereby preventing erroneous actions caused by disconnecting the power device 10 from the power system 30 based solely on whether an overcurrent has occurred.

[0113] Figure 5 A flowchart illustrating the operation process of the abnormal current detection device 100 of this invention detecting ground faults based on abnormal current detection results is shown.

[0114] Reference Figure 5When the abnormal current detection device 100 of this embodiment of the invention starts to drive, it can first control the gate driver 111 to apply a gate voltage to the gate terminal (S500). In this case, the gate voltage can be a normal level gate voltage. In addition, the current flowing into the neutral line of the semiconductor switch 110 can be measured during a constant time period and the measured value can be collected (S502). In addition, the current characteristics can be extracted from the collected measured value (S504).

[0115] The current characteristics can be calculated statistically from the magnitudes of the current, such as the minimum, maximum, or average current. Furthermore, the current characteristics can include not only magnitude but also the change in current magnitude over time (e.g., the slope of the change in current over time).

[0116] If a current characteristic is extracted in step S504, the control unit 130 can determine whether the extracted current characteristic meets a preset abnormal current condition (S506). The preset abnormal current condition can be a condition set based on a stored abnormal current profile. This abnormal current profile can be pre-stored in the abnormal current detection device 100 of this embodiment, or transmitted from the management system 200 to each abnormal current detection device.

[0117] Therefore, the control unit 130 can compare the current characteristics extracted from the collected measurement values ​​with the current characteristics based on the abnormal current curve. If the comparison result shows that the extracted current characteristics match the characteristics based on the abnormal current curve at a preset level or higher, the control unit 130 can determine that the extracted current characteristics are abnormal currents that meet the preset conditions.

[0118] As an example, the abnormal current curve may include at least one of the following: the change in current magnitude over time (e.g., the slope of the change in current over time), the average current magnitude, and the difference between the maximum and minimum current values.

[0119] In this case, based on the current measurement value, if the detected current characteristics, for example, the change in current magnitude over time, satisfy the condition of the change in current magnitude over time according to a preset abnormal current curve, then the control unit 130 can determine that an abnormal current has occurred. Alternatively, if the difference between the average current magnitude or the maximum current value and the minimum current value is greater than or equal to the average current magnitude or the difference between the maximum and minimum values ​​according to the preset abnormal current curve, then the control unit 130 can determine that an abnormal current has occurred.

[0120] Therefore, the control unit 130 controls the gate driver 111 to apply a gate voltage lower than the threshold voltage to disconnect the electrical connection between the source terminal and the drain terminal (S508). In addition, ground fault detection information, including information about the power device 10 associated with the ground fault, can be provided to the management system 200 (S510).

[0121] Conversely, if the current characteristics detected based on the current measurement value do not conform to the abnormal current curve, the control unit 130 can determine that no abnormal current has occurred. Therefore, the control unit 130 can again execute step S502, execute step S504 of receiving the current measurement value and extracting the current characteristics from the received current measurement value, and execute step S506 of determining whether the extracted current characteristics meet the abnormal current conditions.

[0122] On the other hand, if the ground fault detection information is transmitted to the management system 200 in step S510, the control unit 130 can check whether a constant time has elapsed (S512). Furthermore, if the constant time has elapsed, the gate driver 111 can be controlled to apply a gate voltage above a threshold voltage to the gate terminal of the semiconductor switch 110, temporarily connecting the source and drain terminals (S513). In this case, for the temporary connection between the source and drain terminals, the control unit 130 can control the gate driver 111 to temporarily apply a gate voltage to the gate terminal.

[0123] As a gate voltage is temporarily applied to the gate terminal in step S513, the source and drain terminals can be temporarily connected. Therefore, the neutral line can be connected to ground, allowing current in the neutral line to flow to ground. Furthermore, the control unit 130 can collect measurement values ​​of the current flowing through the temporarily connected source and drain terminals (S514).

[0124] Furthermore, the control unit 130 can extract the current characteristic again based on the current measurement value collected in step S514 (S516). Additionally, it can be determined again whether the extracted current characteristic meets the preset abnormal current conditions (S518).

[0125] If the determination result of step S518 is that the re-extracted current characteristic meets the preset abnormal current condition, then the control unit 130 can determine that it is still in the state of detecting an abnormal current from the power device 10. Therefore, the control unit 130 can control the gate driver 111 to apply a gate voltage lower than the threshold voltage (S520). Furthermore, by executing step S512 again, it is determined whether a constant time has elapsed. If the constant time has elapsed, the process of steps S513 to S518 can be repeated to determine again whether the return current meets the preset abnormal current condition.

[0126] Conversely, if the re-evaluation result of step S518 indicates that the restricted return current does not meet the abnormal current condition, the control unit 130 can determine that the power device 10 is in a state where abnormal current no longer occurs due to repair. Therefore, the control unit 130 can control the communication unit 140 to transmit to the management system 200 that the power device 10 is in a normally connected state (S522). Additionally, step S502 can be executed to collect current measurement values ​​from the return current and then execute subsequent steps again.

[0127] On the other hand, the above description illustrates an example of an electrical device 10 connected to a power system 30, wherein an abnormal current detection device 100, including an embodiment of the present invention, is provided between the electrical device 10 and the power system 30. The abnormal current detection device 100 may, as described above, be a solid state circuit breaker (SSCB) including a semiconductor switch 110.

[0128] However, the present invention is not limited to this configuration. That is, a plurality of power devices may be connected to the power system 30, and in this case, an abnormal current detection device 100 according to an embodiment of the present invention may be provided between each power device and the power system.

[0129] Figure 6 An example of an abnormal current detection device according to an embodiment of the present invention is shown, which is configured between each of the plurality of electrical devices and the power system when such a plurality of electrical devices are connected to a power system.

[0130] Reference Figure 6 A power system 30, including a plurality of converters (20-1, 20-2...20-n), can be connected to a plurality of power devices (10-1, 10-2...10-n). In this case, an abnormal current detection device (100-1, 100-2...100-n) according to an embodiment of the present invention can be configured between each power device and the power system 30.

[0131] In this embodiment of the invention, the abnormal current detection device can be connected between the neutral line and ground in the circuit connecting the power device and the power system 30. More specifically, the source terminal of the semiconductor switch 110 provided in each abnormal current detection device can be connected to the neutral line, and the drain terminal of the semiconductor switch 110 can be connected to ground.

[0132] Therefore, the neutral line can be connected to ground via the semiconductor switch 110 of each abnormal current detection device 100. Furthermore, a plurality of abnormal current detection devices (100-1, 100-2…100-n) can be connected to the management system 200. Additionally, the management system 200 can be connected to the display unit 300.

[0133] In this case, the control unit 130 of each abnormal current detection device can determine whether a ground fault current has occurred based on the current flowing into the semiconductor switch 110. Furthermore, if a ground fault current is detected, ground fault detection information can be provided to the management system 200. Thus, the management system 200 can identify the power device experiencing the ground fault current from among the connected plurality of power devices (10-1, 10-2…10-n) based on the information from the abnormal current detection device 100 that received the ground fault detection information.

[0134] On the other hand, the control unit 130 of the abnormal current detection device that detects ground fault current can control the gate driver to apply a gate voltage less than the preset threshold voltage of the semiconductor switch 110 to the gate terminal of the semiconductor switch 110 at one time.

[0135] This disconnects the electrical connection between the source and drain terminals of the semiconductor switch 110, thus breaking the connection between the neutral line and ground between the power device detecting the ground fault current and the power system 30. Therefore, the power device detecting the ground fault current can be disconnected from the power system 30.

[0136] Thus, when the power device is disconnected from the power system 30, the control unit 130 can check whether a constant time has elapsed. Furthermore, if a constant time has elapsed, the gate driver can be controlled to apply a gate voltage greater than the threshold voltage of the semiconductor switch 110 to the gate terminal of the semiconductor switch 110.

[0137] Thus, the source and drain terminals of the semiconductor switch 110 are temporarily connected (temporary connection), and the connection between the neutral line and the ground between the power device and the power system 30 can be temporarily restored.

[0138] Therefore, the current in the neutral line can flow back into the semiconductor switch 110 of the abnormal current detection device. Consequently, the control unit 130 can re-detect whether the ground fault current is included based on the flowing current, and based on the detection result, maintain or disconnect the electrical connection between the source terminal and the drain terminal. In this case, if the electrical connection between the source terminal and the drain terminal is disconnected, the above process can be repeated until the power device that detected the ground fault current is repaired and the abnormal ground fault current is no longer detected.

[0139] The temporary connection control unit 130 can also control the gate voltage to limit the maximum amount of current flowing through the source and drain terminals.

[0140] Thus, when the maximum current that can be energized during a temporary connection is limited, and when the abnormal ground fault current is no longer detected through the aforementioned repair or the like, the control unit 130 can also restore the gate voltage level to the normal level.

[0141] On the other hand, if the judgment result is that no abnormal current is detected, the control unit 130 of each abnormal current detection device can transmit information indicating that no ground fault current is detected (e.g., power equipment normal connection prompt notification) to the management system 200.

[0142] Therefore, the management system 200 can distinguish and display information about power devices that have not detected ground fault current on the display unit 300 among power devices that have detected ground fault current.

[0143] Therefore, even when multiple electrical devices are connected, it is easy to identify and distinguish between electrical devices that have had their ground faults repaired and those that have not yet been repaired.

[0144] On the other hand, while specific embodiments have been described in the above description of the present invention, various modifications can be made without departing from the scope of the present invention. In particular, the embodiments of the present invention describe a configuration in which the display unit 300 is controlled by the management system 200; however, unlike this, the display unit 300 can also be directly controlled by the abnormal current detection device 100 of the embodiments of the present invention.

[0145] For example, the operator can request information from the abnormal current detection device of this embodiment of the invention, which is connected to the electrical equipment being worked on, regarding whether the electrical equipment is operating normally. In response to the request, the abnormal current detection device can also provide information on whether the electrical equipment is operating normally. In this case, information on whether the electrical equipment is operating normally can be provided to the operator without going through the management system.

[0146] On the other hand, the above description illustrates the configuration of controlling the gate driver to apply a gate voltage lower than the threshold voltage of the semiconductor switch to the gate terminal in order to disconnect the electrical connection between the source terminal and the drain terminal.

[0147] However, the configuration of controlling the gate driver to apply a gate voltage less than a threshold voltage to the gate terminal can also include a configuration of controlling the gate driver to not apply a gate voltage to the gate terminal.

[0148] on the other hand, Figure 7 This is a block diagram illustrating the structure of an abnormal current detection device with a semiconductor circuit breaker according to another embodiment of the present invention.

[0149] First, let me explain the essence of the invention in another embodiment of the invention. The abnormal current detection device of the present invention can also be equipped with a detector that can check the repair status of the ground fault when a ground fault is detected in the GFDI, so as to solve the problem of existing GFDIs, that is, when a ground fault is detected, the circuit remains open regardless of whether the detected ground fault is repaired or not, which makes it impossible for the operator to confirm whether the circuit connected to the GFDI to be operated is in a ground fault state.

[0150] On the other hand, the abnormal current detection device of this embodiment can utilize a solid state circuit breaker (SSCB) using a semiconductor switch as the detector. Furthermore, by detecting whether an abnormal current occurs based on the detection threshold of the semiconductor circuit breaker, abnormal currents can be easily detected regardless of their magnitude, and upon detection, the power device can be quickly disconnected from the power system.

[0151] Hereinafter, another embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0152] Referring to the abnormal current detection device 701 of the present invention, the abnormal current detection device 701 of the present invention may include a current detection unit 750, which can check the abnormal current generated in various abnormal phenomena such as overcurrent, short circuit, grounding fault and voltage abnormality at one time according to a preset detection standard.

[0153] Such a current detection unit can be a GFDI (Ground Fault Detection Indicator). The GFDI can include a fuse, which is blown if a current exceeding a predetermined fusing current that would cause the fuse to blow is flowing, thereby enabling the detection of the abnormal current.

[0154] In the following description, for ease of explanation, it is assumed that the current detection unit 750 is a GFDI. However, the present invention is not limited to this. That is, other types of current detection units for detecting abnormal currents, such as ground fault currents or short-circuit currents, can certainly be used as alternatives to the GFDI (750) described below.

[0155] Assuming a GFDI is provided as a current detection unit, the abnormal current detection device 701 of this embodiment will be described. The abnormal current detection device 701 of this embodiment may include a GFDI (750) capable of detecting the presence of abnormal current by the blowing of a fuse, and a semiconductor circuit breaker (SSCB) 700 connected to the GFDI (750). Furthermore, both the GFDI (750) and the semiconductor circuit breaker 700 may be connected to a management system 200, which may be configured to control a display unit 300 connected via wired or wireless means.

[0156] To explain the configuration of the abnormal current detection device 701 in detail, firstly, the abnormal current detection device 701 can be connected to the N-line, which serves as the neutral line, in the circuit constituting the line connecting the power device 10 and the power system 30. In this case, the first pole of the fuse of the GFDI (750) can be connected to the N-line, and the second pole can be grounded. Since the neutral line is grounded through the GFDI (750) connected in this way, the neutral line, i.e., the N-line, can become a grounding line.

[0157] Therefore, the return current flowing through the neutral line can be grounded via the GFDI (750). Thus, when a ground fault occurs in the power unit 10, if an abnormal current such as leakage current or short-circuit current is generated due to the ground fault, this abnormal current can be grounded via the fuse of the GFDI (750). In this case, if the abnormal current exceeds the fuse blowing current of the GFDI (750), the fuse can be blown. If the abnormal current causes the fuse to blow, the GFDI (750) can notify the management system 200 that an abnormal current has occurred between the power unit 10 and the power system 30.

[0158] On the other hand, the abnormal current detection device 701 of this embodiment may have a semiconductor circuit breaker 700 connected to the GFDI (750). The semiconductor circuit breaker 700 can receive ground fault detection information detected by the GFDI (750) through the connected GFDI (750) and can be activated according to the received ground fault detection information.

[0159] The semiconductor circuit breaker 700 may include a semiconductor switch 710 configured to allow current to flow between a source terminal and a drain terminal based on a voltage applied to a gate driver 711. Furthermore, the semiconductor circuit breaker 700 may include a gate driver 711 that applies a voltage to the gate terminal of the semiconductor switch 710. Additionally, the semiconductor circuit breaker 700 may include a control unit 730 that controls the gate driver 711.

[0160] The control unit 730 can control the voltage applied to the gate terminal (hereinafter, the gate voltage) by controlling the gate driver 711. By controlling such a gate voltage, the source terminal and drain terminal of the semiconductor switch 710 can be electrically connected or disconnected. More specifically, the control unit 730 can control the gate driver 711 to apply a gate voltage greater than a preset threshold voltage to the gate terminal of the semiconductor switch 710. This allows the source terminal and drain terminal to be electrically connected, enabling current flow. Thus, when the source terminal and drain terminal are electrically connected, the control unit 730 can also control the maximum amount of current that can be conducted between the source terminal and drain terminal by controlling the magnitude of the gate voltage.

[0161] Conversely, the control unit 730 can control the gate driver 711 to apply a gate voltage less than a preset threshold voltage to the gate terminal of the semiconductor switch 710. This opens the connection between the source and drain terminals, thereby disconnecting the electrical connection.

[0162] The configuration of controlling the gate driver to apply a gate voltage to the gate terminal that is less than the threshold voltage of the semiconductor switch may include a configuration of controlling the gate driver not to apply a gate voltage to the gate terminal.

[0163] On the other hand, when the source terminal and drain terminal are electrically connected, the neutral line can be connected to ground via the semiconductor switch 710. Therefore, a bypass circuit connecting the neutral line to ground can be formed via the semiconductor switch 710.

[0164] More specifically, the GFDI (750) can be connected to the grounding wire in the line connecting the electrical device 10 to the power system 30, and the semiconductor circuit breaker 700 can be connected to the grounding wire. In this case, as Figure 7 As shown, the source terminal and drain terminal of the semiconductor switch 710 can be connected to the ground wire respectively.

[0165] More preferably, the source terminal can be connected between the neutral line and the first terminal of the connected GFDI (750), and the drain terminal can be connected between the ground and the second terminal of the connected GFDI (750).

[0166] When connected in this way, a bypass circuit can be formed that connects the neutral line to ground via a semiconductor switch 710, bypassing the GFDI (750) to connect the neutral line to ground. Therefore, even if the fuse located in the GFDI (750) blows, causing an open circuit between the neutral line and the ground, grounding can be established through the bypass circuit, thereby enabling an electrical connection between the power device 10 and the power system 30.

[0167] On the other hand, by configuring the semiconductor circuit breaker 700 in this way to form a bypass circuit that bypasses the GFDI (750), the semiconductor circuit breaker 700 can detect whether there is an abnormal current flowing through the grounding wire connected to the GFDI (750) when a ground fault is detected by the GFDI (750).

[0168] More specifically, for example, if a ground fault occurs causing the fuse of the GFDI (750) to blow, thus opening the grounding wire, the semiconductor circuit breaker 700 can be activated. Furthermore, since the fuse has blown, current in the neutral line can flow to the semiconductor circuit breaker 700 through the bypass circuit. Therefore, the control unit 730 can detect the current flowing in the neutral line by detecting the current flowing to the semiconductor circuit breaker 700. Additionally, it can determine whether the current flowing in the neutral line contains an abnormal current based on the detected current and a preset detection value.

[0169] As an example, if the current detected from the neutral line is greater than or equal to a preset current value (ground fault detection current value), the control unit 730 of the semiconductor circuit breaker 700 can determine that the current flowing in the neutral line contains an abnormal current. Therefore, the control unit 730 of the semiconductor circuit breaker 700 can control the gate driver 711 to apply a gate voltage less than a threshold voltage, thereby disconnecting the connection between the source terminal and the drain terminal. Thus, the bypass circuit can be disconnected.

[0170] That is, if the abnormal current, such as a grounding fault, between the power device 10 and the power system 30 is not repaired, the power device 10 can be disconnected from the power system 30.

[0171] Thus, based on the result of detecting the current flowing to the grounding wire, if the connection between the source terminal and the drain terminal is disconnected, the control unit 730 of the semiconductor circuit breaker 700 can control the gate driver 711 to apply a voltage above the threshold voltage at a preset time interval.

[0172] This allows the formation of a bypass circuit that reconnects the neutral line to ground, through which the current in the neutral line can flow into the semiconductor circuit breaker 700. In this case, the control unit 730 can detect the current flowing in the neutral line again and, based on the detection result, control the gate driver 711 to apply a gate voltage less than a threshold voltage, thereby enabling the connection between the source and drain terminals to be disconnected again.

[0173] On the other hand, if the result of detecting the current flowing in the grounding wire is that the current flowing in the grounding wire is a normal current, the control unit 730 of the semiconductor circuit breaker 700 can control the gate driver 711 to maintain a gate voltage above the applied threshold voltage. Thus, while connecting the source and drain terminals, the neutral line and ground can bypass the GFDI (750) where the fuse has blown and be connected via the bypass circuit. Therefore, the circuit connecting the power device 10 and the power system 30 can be closed.

[0174] Therefore, even if the fuse of the GFDI (750) is blown, the power device 10 can still be connected to the power system 30. That is, even if the GFDI (750) whose fuse was blown due to the abnormal current is not replaced after the ground fault is repaired, the abnormal current detection device 701 of this embodiment can still electrically connect the power device 10 to the power system 30.

[0175] On the other hand, when the power device 10 is connected to the power system 30 via such a bypass circuit, the connection can be a temporary connection between the power device 10 and the power system 30 until the fuse in the GFDI (750) is replaced. That is, when the current is conducted again through the two poles of the fuse after the GFDI (750) is replaced, the semiconductor circuit breaker 700 can be deactivated again. Thus, the neutral line and ground can be reconnected via the GFDI (750). To distinguish it from the connection formed via the GFDI (750), the connection between the power device 10 and the power system 30 via such a bypass circuit is called a temporary connection.

[0176] On the other hand, by temporarily connecting the power device 10 to the power system 30, the semiconductor circuit breaker 700 can determine whether the connection between the power device 10 and the power system 30 is normal, i.e., whether there is abnormal current flow, based on the current flowing through the grounding wire. Furthermore, the determination result of whether the abnormal current detection is in a normal state can be transmitted to the management system 200 through this temporary connection. To transmit the normal state determination result in this way, the semiconductor circuit breaker 700 may also include a communication unit 740, which is controlled by the control unit 730 and is wirelessly or wiredly connected to the management system 200.

[0177] The management system 200 can be a system for managing abnormal current detection results received from the semiconductor circuit breaker 700. For example, the management system 200 can be a PMS (Power Management System). The management system 200 can determine whether an abnormal current has occurred in the power device 10 based on the abnormal current detection information received from the GFDI (750) of the abnormal current detection device 701 of this embodiment. In addition, the system can receive the judgment result of whether an abnormal current exists from the semiconductor circuit breaker 700 of the abnormal current detection device 701 of this embodiment, and detect whether an abnormal current exists between the power device 10 and the power system 30 (whether the abnormal current exists or not). Furthermore, the display unit 300 can be controlled to display the judgment result of whether the received abnormal current exists or not, so that the operator can easily identify whether the abnormal current exists or not.

[0178] On the other hand, the semiconductor circuit breaker 700 can be activated from a non-activated state according to the operating state of the GFDI (750). That is, as Figure 7 As shown, the abnormal current detection device 701 of the present invention may have a semiconductor circuit breaker 700 and a GFDI (750) connected to each other, and may be configured such that the control unit 730 of the semiconductor circuit breaker 700 receives the abnormal current detection information detected by the GFDI (750).

[0179] In addition, if the current is in a normal state, i.e. within a normal range, such as a current less than the preset fuse breaking current, flows through the fuse terminals of the GFDI (750), the semiconductor circuit breaker 700 can switch to an inactive state and remain inactive.

[0180] Figure 8 As an example of the abnormal current detection device 701 of such an embodiment of the present invention detecting abnormal current, a flowchart showing the operation process of detecting ground fault current and determining whether ground fault current exists is provided.

[0181] Reference Figure 8 First, the GFDI (750) of the abnormal current detection device 701 in this embodiment of the invention can detect whether the flowing current has blown the fuse (S800). Furthermore, if an abnormal current exceeding a preset value causes the fuse to blow, an activation signal can be sent to the control unit 730 of the semiconductor circuit breaker 700 after detection (S801), and abnormal current detection information (e.g., ground fault detection information) indicating the occurrence of an abnormal current can be sent to the management system 200 (S802). The activation signal can be the abnormal current detection information.

[0182] That is, if an abnormal current is detected, the GFDI (750) can transmit abnormal current detection information to the management system 200 and the semiconductor circuit breaker 700, and the semiconductor circuit breaker 700 can receive the abnormal current detection information and switch to an active state. In the following description, for ease of explanation, the case of detecting a ground fault current is assumed, and therefore the abnormal current detection information is assumed to be ground fault current detection information for explanation.

[0183] Therefore, the control unit 730 of the semiconductor circuit breaker 700 can switch from an inactive state to an active state (S810). The inactive state is a state that maintains the lowest power consumption state so that the semiconductor circuit breaker 700 can receive the activation signal, and can also be called a sleep state or energy-saving state.

[0184] Conversely, the active state can indicate that the semiconductor circuit breaker 700 can detect the current flowing into the semiconductor switch 710, determine whether the detected current is an overcurrent exceeding a preset value, and control the electrical connection between the source terminal and the drain terminal of the semiconductor switch 710 based on the determination result.

[0185] On the other hand, if the semiconductor circuit breaker 700 is activated, the control unit 730 can check whether a preset first time has elapsed (S811). Furthermore, if the preset first time has elapsed, the control unit 730 can apply a gate voltage higher than a threshold voltage to electrically connect the source and drain terminals of the semiconductor switch 710 (S812). This allows the formation of a bypass circuit that connects the neutral line to ground via the semiconductor switch 710 and bypasses the GFDI (750) where the fuse has blown. Consequently, the current flowing in the neutral line (e.g., return current) can flow into the semiconductor switch 710.

[0186] Therefore, the control unit 730 can detect whether the current flowing into the neutral line of the semiconductor switch 710 is an abnormal current such as a short-circuit current or a leakage current (S813). For example, if the current flowing into the neutral line of the semiconductor switch 710 is an overcurrent exceeding a preset current value, the control unit 730 can determine that an abnormal current is flowing in the neutral line.

[0187] If the determination result of step S813 is that the current flowing in the neutral line is the abnormal current, then the control unit 730 can control the gate driver 711 to apply a preset voltage less than a threshold voltage to the gate terminal of the semiconductor switch 710 (S814). This disconnects the electrical connection between the source and drain terminals of the semiconductor switch 710, thereby disconnecting the bypass circuit. Thus, by the blowing of the GFDI (750) fuse and the disconnection of the bypass circuit, the power device 10 connected via the neutral line can be disconnected from the power system 30.

[0188] Therefore, the control unit 730 can execute step S811 again to check whether the first time has elapsed. Furthermore, if the check result of step S811 indicates that the first time has elapsed, the process from step S812 to step S813 can be executed again.

[0189] Conversely, if no abnormal current is detected in step S813, the control unit 730 can determine that the power device 10 has been properly connected to the power system 30 through repair or other means. Therefore, the control unit 730 can maintain a gate voltage above the threshold voltage applied to the gate terminal.

[0190] The control unit 730 can check whether a preset second time has elapsed while a gate voltage above the threshold voltage is applied to the gate terminal (S815). Furthermore, if the second time has elapsed while a gate voltage above the threshold voltage is applied to the gate terminal, step S813 can be executed again to determine whether the current flowing into the neutral line of the semiconductor switch 710 is an abnormal current. That is, even if no abnormal current is detected, as long as the preset time (second time) has elapsed, it can be determined again whether an abnormal current exists in the neutral line where the abnormal current was previously detected.

[0191] In addition, if an abnormal current is detected again based on the judgment result of step S813, step S814 can be executed to control the gate driver 711 to apply a gate voltage lower than the threshold voltage again, and step S811 can be executed again to repeat the process from step S811 to step S813.

[0192] Therefore, before the semiconductor circuit breaker 700 receives the inactive signal, it is possible to prevent the connection between the power device 10 and the power system 30 from being temporarily undetected due to the ground fault not being repaired.

[0193] On the other hand, if the check result of step S815 has not passed the preset second time, the control unit 730 can check whether an inactive signal is received from GFDI (750) (S816).

[0194] On the other hand, the GFDI (750) can determine whether the fuse connection has been restored by replacement (S803). For example, the GFDI (750) can determine that the fuse has been restored when the electrical connection between the two terminals of the fuse is restored after the fuse has blown and broken. Furthermore, if the electrical connection between the two terminals of the fuse is restored, a deactivation signal can be transmitted to the semiconductor circuit breaker 700 (S804). This deactivation signal can be a signal indicating to the GFDI (750) that it can operate normally by replacing the blown fuse.

[0195] In step S804, if the inactive signal is transmitted from the GFDI (750), the semiconductor circuit breaker 700 can confirm the reception of the inactive signal in step S816. Therefore, the control unit 730 can transmit information to the management system 200 indicating that there is no abnormal current in the connection between the power device 10 and the power system 30 (e.g., no ground fault information) (S817). Additionally, the state of the semiconductor circuit breaker 700 can be switched to an inactive state.

[0196] Therefore, the semiconductor circuit breaker 700 of the abnormal current detection device 701 in this embodiment of the invention can be activated in a non-activated state based on ground fault detection information received from the GFDI (750), and become inactive based on a normal operation signal received from the GFDI (750). That is, the semiconductor circuit breaker 700 of the abnormal current detection device 701 in this embodiment of the invention can switch between an active state and an inactive state in conjunction with the operation state of the GFDI (750).

[0197] On the other hand, the management system 200 can receive ground fault detection information received from the GFDI (750) in step S802. Furthermore, it can retrieve information about the power device 10 connected to the GFDI (750) that transmitted the received ground fault detection information, i.e., the abnormal current detection device 701 of this embodiment. Additionally, the retrieved information about the power device 10 can be displayed on the display unit 300 as information associated with the detected ground fault. Furthermore, the management system 200 can manage the information associated with the power device 10 based on the received ground fault detection information.

[0198] For example, the management system 200 can update the status of the power device 10 connected to the abnormal current detection device 701 that detects the abnormal current to an abnormal state (S821). In this case, if the management system 200 manages whether a plurality of power devices are grounded or not, the number of power devices that have detected grounding faults can be increased.

[0199] On the other hand, the management system 200 can update the information of the power device again based on the information received from the abnormal current detection device 701 of this embodiment. For example, in step S817, the abnormal current absence information (e.g., ground fault absence information) received from the semiconductor circuit breaker 700 of the abnormal current detection device 701 can be received from the semiconductor circuit breaker 700 under the following circumstances: the control unit 730 of the semiconductor circuit breaker 700 determines that the current of the neutral line connected to the power device 10 is in a normal current state, and the fuse of the blown GFDI (750) has been replaced, so that the control unit 730 of the semiconductor circuit breaker 700 receives an inactive signal from the GFDI (750). Therefore, when the abnormal current absence information is received from the semiconductor circuit breaker 700 of the abnormal current detection device 701 in step S817, the management system 200 can determine that the cause of the abnormal current in the power device 10 has been repaired.

[0200] Therefore, the management system 200 can update the information of the power device again based on the received information that the abnormal current does not exist (S822). In this case, the management system 200 retrieves the power device 10 associated with the received abnormal current detection information (e.g., ground fault detection information) and changes the status of the retrieved power device 10 from an abnormal state (e.g., ground fault state) to a normal state. In addition, the display unit 300 can be controlled to display the updated status information of the power device 10.

[0201] On the other hand, although the stated Figure 8Although not shown, the control unit 730 of the semiconductor circuit breaker 700 in this embodiment of the invention can also control the communication unit 740 to transmit information about whether an abnormal current is detected to the display unit 300. For example, if the control unit 730 receives a request for information about whether an abnormal current is detected through the display unit 300 connected to the communication unit 740, it can transmit information about whether an abnormal current is detected in response to the request. That is, even before transmitting information about the absence of abnormal current after receiving an inactive signal, the control unit 730 can transmit the result of whether an abnormal current is detected in step S813 to the display unit 300 according to a request for whether an abnormal current is detected.

[0202] Furthermore, although the stated Figure 8 Although not explicitly stated, the control unit 730 of the semiconductor circuit breaker 700 in this embodiment of the invention only requires the aforementioned... Figure 8 If the abnormal current detection result in step S813 is that no abnormal current is detected, the system management 200 can be sent a message indicating that no abnormal current was detected even before receiving the inactivation signal. Therefore, the system management 200 can display the information received on the display unit 300 indicating that no abnormal current was detected in the corresponding power unit. Thus, operators can use the display unit 300 to perform GFDI (750) replacement work only on power units where no abnormal current was detected, such as power units where grounding faults have been repaired. This helps prevent safety accidents for operators.

[0203] On the other hand, as described above, the abnormal current detection device 701 of this embodiment is described as an example where a ground fault is determined to have occurred when the current flowing in the neutral line is an overcurrent exceeding a preset current magnitude, but the present invention is not limited to this. That is, as described above, the present invention can detect not only whether there is an overcurrent, but also whether there is an abnormal current through other means. If an abnormal current is detected, the connection between the power device 10 and the power system 30 is disconnected.

[0204] For example, with GFDI (750), since ground faults are detected by the blowing of a fuse, there is a possibility that a temporary overcurrent or inrush current that occurs temporarily and then returns to normal is mistaken for an overcurrent caused by a ground fault. To address this, the abnormal current detection device 701 of this embodiment can determine whether the current detected from the neutral line meets preset abnormal current conditions, thereby avoiding misjudging a temporary overcurrent as an overcurrent and disconnecting the power device 10 from the power system 30 in the event of a temporary overcurrent such as a noise overcurrent or inrush current.

[0205] Furthermore, only when the detected current meets the preset abnormal current conditions, the semiconductor circuit breaker 700 connects the ground and neutral lines via the semiconductor switch 710, thereby maintaining the connection between the power device 10 and the power system 30. In this case, even if the noise overcurrent or inrush current causes the fuse of the GFDI (750) to blow, the connection between the power device 10 and the power system 30 can be maintained using the bypass circuit through the semiconductor switch 710.

[0206] Figure 9 This describes how the control unit 730 of the semiconductor circuit breaker 700 in the abnormal current detection device 701 of this embodiment determines whether an abnormal current is flowing from the result of the detected current. Figure 8 The flowchart of the action process of step S13.

[0207] Reference Figure 9 Upon detecting the fuse's melting from the GFDI (750), if an activation signal is received from the GFDI (750), the semiconductor circuit breaker 700 can form a bypass circuit that connects the neutral line to ground, bypassing the GFDI (750). Furthermore, the current flowing into the neutral line through the bypass circuit can be measured over a constant time to collect a measurement value (S900). Additionally, the current characteristic can be extracted from the collected measurement value (S902).

[0208] The current characteristics can be calculated based on statistical results regarding current magnitude, such as minimum or maximum current magnitude and average current magnitude. Alternatively, the current characteristics may include not only magnitude but also the change in current magnitude over time (e.g., the slope of the change in current over time).

[0209] After the current characteristics are extracted in step S902, the control unit 730 can determine whether the extracted current characteristics meet the preset abnormal current conditions (S904). The preset abnormal current conditions can be conditions set based on stored abnormal current profiles. These abnormal current profiles can be pre-stored in the abnormal current detection device 701 of this embodiment, or they can be transmitted from the management system 200 to each abnormal current detection device.

[0210] Therefore, the control unit 730 can compare the current characteristics extracted from the collected measurements with the current characteristics based on the abnormal current curve. The control unit 730 can determine the extracted current characteristics as an abnormal current that meets the preset conditions only if the extracted current characteristics match the characteristics based on the abnormal current curve at a level higher than a preset threshold.

[0211] As an example, the abnormal current curve may include information such as the change in current magnitude over time (e.g., the slope of the change in current over time), the average current magnitude, and the difference between the maximum and minimum current values.

[0212] In this case, the control unit 730 can determine that an abnormal current has occurred based on the current measurement value, provided that the detected current characteristics, such as the change in current magnitude over time, meet the conditions set according to the change in current magnitude over time in a preset abnormal current curve. Alternatively, if the difference between the average current magnitude or the maximum current value and the minimum current value is greater than or equal to the average current magnitude or the difference between the maximum and minimum values ​​in the preset abnormal current curve, the control unit 730 can determine that an abnormal current has occurred (S906). Therefore, the control unit 730 can execute the aforementioned... Figure 8 In step S814, the gate voltage is turned off, and the above can be executed again. Figure 8 In step S811, check if the first time has elapsed. Alternatively, if the first time has elapsed, proceed with the steps following S811.

[0213] Conversely, if the current characteristics detected based on the current measurement value do not conform to the abnormal current curve, the control unit 730 can determine that no abnormal current has occurred (S908). Therefore, the control unit 730 can, after the... Figure 8 The second time set in step S815 or the aforementioned Figure 8 Before receiving an inactive signal from the GFDI (750) in the detection result of step S816, the gate driver 711 is controlled to apply a gate voltage above the threshold voltage. Therefore, it is possible to maintain the state in which a bypass circuit connecting the neutral line and ground is formed.

[0214] Therefore, even if a brief, noisy overcurrent causes the fuse of the GFDI (750) to blow, based on the abnormal current determination result, the abnormal current detection device 701 of this embodiment can maintain the connection between the power device 10 and the power system 30 through the bypass circuit. Thus, the power device 10 can operate normally.

[0215] On the other hand, the management system 200 that receives the abnormal current detection information of the GFDI (750) can display the abnormal status, thereby enabling the operator to replace the GFDI (750).

[0216] As described above, the present invention forms a bypass circuit between the neutral line and the ground by setting a semiconductor circuit breaker 700, so that the current of the neutral line flows to the ground through the semiconductor switch 710. It is possible to determine whether there is abnormal current flow such as leakage current, short circuit current or ground fault current based on the state of the current flowing through the semiconductor switch 710.

[0217] Therefore, for the abnormal current detection device 701 of this embodiment of the invention, if there is a grounding fault between the power device 10 and the power system 30, the overcurrent caused by the grounding fault may flow into the semiconductor switch 710. In such a case, in order to prevent the semiconductor switch 710 from burning out and to prevent safety accidents caused by the inflow of the overcurrent, the control unit 730 may also limit the maximum amount of current that can flow into the semiconductor switch 710.

[0218] As an example, the semiconductor switch 710 can determine the maximum amount of current that can flow from the source terminal to the drain terminal based on the magnitude of the gate voltage. Therefore, the control unit 730 can limit the gate voltage applied to the gate terminal to within a preset range of the threshold voltage. In this case, since the magnitude of the current flowing to the bypass circuit via the semiconductor switch 710 can be limited, the abnormal current curve used to determine the abnormal current can also be determined based on the magnitude of the gate voltage.

[0219] On the other hand, if no abnormal current is detected, the control unit 730 can limit the magnitude of the current flowing from the neutral line to ground via the semiconductor switch 710. However, if no abnormal current is detected, for example, if the ground fault has been repaired, the control unit 730 may not limit the magnitude of the current output from the semiconductor switch 710. That is, by applying a gate voltage of a normal magnitude to the gate terminal, the control unit 730 may not limit the magnitude of the current flowing to the bypass circuit.

[0220] Therefore, if the typically large gate voltage is called the reference gate voltage, and the restricted gate voltage applied to the gate terminal to detect the presence of the abnormal current is called the test voltage, then although both the reference gate voltage and the test voltage can be voltages above the threshold voltage, the test voltage can be a voltage lower than the reference gate voltage.

[0221] On the other hand, the above description shows an example of an electrical device 10 connected to a power system 30, with an abnormal current detection device 701 of the present invention, including a GFDI (750) and a semiconductor circuit breaker 700, provided between the electrical device 10 and the power system 30. However, a plurality of electrical devices may be connected to the power system 30, in which case the abnormal current detection device 701 of the present invention may be provided between each electrical device and the power system.

[0222] Figure 10 An example of an abnormal current detection device according to an embodiment of the present invention is shown, which is connected to a power system and configured between the power devices and the power system.

[0223] Reference Figure 10 A power system 30, including a plurality of converters (20-1, 20-2...20-n), can be connected to a plurality of power devices (10-1, 10-2...10-n). In this case, an abnormal current detection device (701-1, 701-2...701-n) according to an embodiment of the present invention can be configured between each power device and the power system 30.

[0224] In this embodiment of the invention, the abnormal current detection device can be connected between the neutral line and the ground in the line connecting the power device to the power system. More specifically, the GFDI (750-1, 750-2...750-n) of each abnormal current detection device can be connected between the neutral line and the ground, and the semiconductor circuit breaker (700-1, 700-2...700-n) connected to the neutral line can bypass each GFDI (750-1, 750-2...750-n) and be connected to the ground, thereby forming a bypass circuit. Furthermore, the GFDI (750-1, 750-2...750-n) of each abnormal current detection device (701-1, 701-2...701-n) and the semiconductor circuit breaker (700-1, 700-2...700-n) can each be connected to the management system 200. Additionally, the management system 200 can be connected to the display unit 300.

[0225] In this case, each GFDI (750-1, 750-2, ..., 750-n) connected to each center line of the neutral line connecting the power devices (10-1, 10-2, ..., 10-n) to the power system 30 can determine at once whether there is an abnormal current flow between the power device 10 and the power system 30. Furthermore, based on the fuse blow detection results of each GFDI, information on the occurrence of abnormal current can be provided to the management system 200. Thus, the management system 200 can collect information on the power devices (10-1, 10-2, ..., 10-n) experiencing abnormal current based on the information received from the GFDIs connected to the power device 10 where the abnormal current occurred (abnormal current detection information).

[0226] On the other hand, the semiconductor circuit breaker of the abnormal current detection device connected to the power device experiencing abnormal current can be activated based on the abnormal current detection information. Thus, by applying a preset gate voltage to the gate terminal, a bypass circuit is formed that bypasses the GFDI and connects the neutral line of the power device to ground, and the current flowing in the formed bypass circuit is detected. Furthermore, the detection result can be used to determine whether there is abnormal current flowing in the neutral line.

[0227] If the judgment result does not detect any abnormal current, each semiconductor circuit breaker can transmit information indicating that no abnormal current was detected to the management system 200. Therefore, the management system 200 can distinguish and display information on the display unit 300 regarding the electrical devices that no longer detect the abnormal current among those that did. Thus, even with multiple electrical devices connected, it is easy to identify and distinguish the electrical devices experiencing abnormal current.

[0228] On the other hand, although specific embodiments have been described in the above description of the present invention, various modifications can be made without departing from the scope of the present invention. In particular, the embodiments of the present invention have described a configuration in which the management system 200 controls the display unit 300, but unlike this, the abnormal current detection device 701 of the embodiments of the present invention can also directly control the display unit 300.

[0229] For example, the operator can request information from the abnormal current detection device of this embodiment of the invention, which is connected to the electrical equipment being worked on, regarding whether the electrical equipment is operating normally. The abnormal current detection device can also provide this information in response to the request. In this case, the information regarding whether the electrical equipment is operating normally can be provided to the operator without going through the management system.

[0230] On the other hand, the above description illustrates that the abnormal current detection device of the present invention is composed of a GFDI (750) and a semiconductor circuit breaker 700 driven separately from each other, but this is only an embodiment of the present invention and the present invention is not limited thereto.

[0231] For example, the control unit 730 of the semiconductor circuit breaker 700 may be a control unit that controls all operations of the abnormal current detection device according to the embodiment of the present invention. In this case, the GFDI and the semiconductor switch can be operated through the control unit. That is, the GFDI can transmit information to the control unit regarding whether the fuse has blown.

[0232] Therefore, the control unit can transmit ground fault detection information to the management system 200 through the control communication unit. Additionally, the control unit can activate a semiconductor switch and apply a voltage exceeding a threshold voltage to the gate terminal of the semiconductor switch to form a bypass circuit that bypasses the GFDI.

[0233] In addition, through Figure 8 The described operation process can determine whether the current flowing into the neutral line through the bypass circuit is an abnormal current, and provide the judgment result to the management system 200.

[0234] Furthermore, if the blown fuse of the GFDI is replaced, and current is made to flow through the two terminals of the GFDI fuse, the GFDI can transmit the current flow result to the control unit 730. Therefore, the control unit 730 can deactivate the semiconductor switch based on the information received from the GFDI.

[0235] Therefore, the electrical connection between the source and drain terminals of the semiconductor switch is broken, thereby disconnecting the bypass circuit. Consequently, the neutral current can be grounded via the GFDI.

[0236] In addition, when the semiconductor switch becomes inactive, the control unit 730 can send information to the management system that the ground fault does not exist, and prompt the management system 200 that the ground fault state detected from the power device has been eliminated.

[0237] Furthermore, the above description assumes that the current sensing unit is connected between the neutral line and the ground, but unlike this, the neutral line of the power device and the power system can of course also be connected via the current sensing unit.

[0238] In this case, as described above, if we assume the current sensing unit is a GFDI (GF-connected circuit breaker), then the first terminal of the GFDI fuse can also be connected to the N (neutral) terminal of the power system, and the second terminal of the GFDI fuse can also be connected to the N terminal of the power device. In this case, the neutral wire connecting the second terminal to the N terminal of the power device can be connected to ground.

[0239] The present invention described above can also be implemented as computer-readable code on a medium containing a program. Computer-readable media include all kinds of recording devices that store data readable by a computer system. Examples of computer-readable media include HDDs (Hard Disk Drives), SSDs (Solid State Disks), SDDs (Silicon Disk Drives), ROMs, RAMs, CD-ROMs, magnetic disks, floppy disks, optical data storage devices, etc., and also include those implemented via carrier waves (e.g., transmitted over the Internet). Additionally, the computer may also include a control unit for the semiconductor circuit breaker. Therefore, the above detailed description should not be construed as limiting in all respects, but should be considered exemplary. The scope of the invention should be determined according to a reasonable interpretation of the appended claims, and all modifications made within the equivalent scope of the invention are included within the scope of the invention.

Claims

1. An abnormal current detection device, characterized in that, include: A semiconductor switch is connected to any one of a plurality of circuits that connect an electric system to an electric device, thereby connecting the electric system to the electric device. A gate driver applies a gate voltage to the semiconductor switch; as well as The control unit determines whether a ground fault current exists between the connected power system and the power device based on the current flowing into the semiconductor switch. Based on the determination result, it controls the gate driver to disconnect the power device from the power system. If the power device is disconnected from the power system, it controls the gate driver to connect the power device and the power system at a preset constant time period. Then, it determines whether a ground fault current exists again based on the current flowing into the semiconductor switch, and controls the gate driver again based on the re-determination result to disconnect the power device from the power system or keep the power device connected to the power system.

2. The abnormal current detection device according to claim 1, characterized in that, Any one of the plurality of circuits is the neutral line connecting the electrical device to the power system. The neutral wire is connected to the ground. The source terminal of the semiconductor switch is connected to the neutral line, and the drain terminal of the semiconductor switch is connected to the ground.

3. The abnormal current detection device according to claim 2, characterized in that, If the power device is disconnected from the power system, the control unit applies a limited-level gate voltage to the gate terminal of the semiconductor switch at a constant time period, temporarily connecting the source terminal and the drain terminal, thereby determining whether a ground fault current exists. If the re-evaluation result indicates that there is no ground fault current, then the gate voltage of the restricted level is restored.

4. The abnormal current detection device according to claim 3, characterized in that, The restricted gate voltage is a voltage above a threshold voltage that enables electrical connection between the source and drain terminals in the semiconductor switch. It is a voltage that is lower than the level of the gate voltage after recovery.

5. The abnormal current detection device according to claim 1, characterized in that, The management system, which is communicatively connected to the abnormal current detection device, transmits a reference current to the abnormal current detection device based on ground fault detection information, including the detection result of the ground fault current and information associated with the power device that detected the ground fault current. The reference current is used by the abnormal current detection device to further determine whether the ground fault current exists. The abnormal current detection device determines whether the ground fault current exists by comparing the detection result of the current flowing into the semiconductor switch from the power device and the power system connected at the constant time period with the reference current.

6. The abnormal current detection device according to claim 5, characterized in that, The control unit compares the analysis results of the current characteristics flowing into the semiconductor switch with the abnormal current characteristics based on a preset abnormal current curve. Based on the comparison results, and according to whether the analyzed current characteristics match the abnormal current characteristics, it determines or further determines whether the ground fault current exists. The abnormal current curve includes at least one of the following: the change in current magnitude over time, the average current magnitude, and the difference between the maximum and minimum current values, provided by the management system.

7. A control method for an abnormal current detection device, The abnormal current detection device includes a semiconductor switch connected to any one of a plurality of circuits connecting the power system and the power device, characterized in that, The control method includes: The step of controlling the semiconductor switch to connect the power device to the power system; The steps include detecting the current flowing between the connected power device and the power system, and determining whether a ground fault current exists based on a preset ground fault detection current. The step of controlling the semiconductor switch based on the result of the first determination to disconnect the power device from the power system; Check whether the preset constant time has elapsed; If the result of the check is that the constant time has elapsed, then the step of controlling the semiconductor switch to reconnect the power device to the power system; and The steps include detecting the current flowing between the reconnected power device and the power system, and determining whether there is a ground fault current based on a preset reference current. Based on the result of the second judgment, the step of checking whether the constant time has elapsed is then executed, followed by the second judgment step, or the step of maintaining the connection between the power device and the power system.

8. The control method for the abnormal current detection device according to claim 7, characterized in that, Any one of the plurality of circuits is the neutral line connecting the electrical device to the power system. The neutral wire is connected to the ground. The source terminal of the semiconductor switch is connected to the neutral line, and the drain terminal of the semiconductor switch is connected to the ground. The step of controlling the semiconductor switch to connect the power device to the power system is to apply a first gate voltage above a preset threshold voltage to the gate terminal of the semiconductor switch, so as to electrically connect the source terminal and the drain terminal of the semiconductor switch. The step of controlling the semiconductor switch to reconnect the power device to the power system is to apply a second gate voltage, which is above the threshold voltage and below the first gate voltage, to the gate terminal of the semiconductor switch.

9. An abnormal current detection device, characterized in that, include: A current detection unit is configured in any one of a plurality of circuits that connect the power system and the power device, connects the power system and the power device, detects the presence of abnormal current based on preset detection information, and disconnects the power device from the power system based on the abnormal current detection result. A semiconductor switch, connected to the current sensing unit, forms a bypass circuit that bypasses the current sensing unit. The semiconductor switch includes a gate driver. In order to form the bypass circuit, the gate driver applies a gate voltage to control the first terminal and the second terminal, which are respectively connected to the first and second poles of the current sensing unit, to be electrically connected or to disconnect the first terminal from the second terminal. as well as If the power device is disconnected from the power system based on whether the current detection unit detects an abnormal current, the control unit electrically connects the first terminal and the second terminal, determines whether an abnormal current exists based on the current flowing in the bypass circuit through the connected first terminal and the second terminal, and controls the semiconductor switch based on the determination result to disconnect the bypass circuit or maintain the connection between the power system and the power device through the bypass circuit.

10. The abnormal current detection device according to claim 9, characterized in that, The current detection unit is a ground fault detection indicator, which includes a fuse that blows when an overcurrent exceeding a preset fusing current flows in. The fuse is connected between the neutral wire and ground in one of the plurality of circuits that connect the power system to the power device.

11. The abnormal current detection device according to claim 10, characterized in that, The first terminal of the fuse is connected to the neutral wire, and the second terminal of the fuse is connected to the ground wire. The first terminal of the semiconductor switch is connected between the first electrode of the fuse and the neutral line, and the second terminal of the semiconductor switch is connected between the second electrode of the fuse and the ground.

12. The abnormal current detection device according to claim 10, characterized in that, The control unit, in conjunction with the melting of the fuse, activates the inactive semiconductor switch. When the blown fuse is replaced and the first and second terminals of the fuse are electrically connected, the control unit switches the activated semiconductor switch to an inactive state.

13. The abnormal current detection device according to claim 9, characterized in that, The control unit forms a first bypass circuit by controlling the semiconductor switch to apply a first gate voltage exceeding a preset threshold voltage. The presence of the abnormal current is determined by the formed first bypass circuit. If the result of the determination is that there is no abnormal current, the control unit controls the semiconductor switch to apply a second gate voltage greater than the first gate voltage to form a second bypass circuit for maintaining the connection between the power system and the power device.

14. An abnormal current detection device, characterized in that, include: The current detection unit connects the neutral line to the ground in a plurality of circuits that connect the power system and the power device, detects abnormal current flowing in the neutral line, and disconnects the power device from the power system if an abnormal current is detected. as well as A semiconductor circuit breaker includes a semiconductor switch and a control unit. The semiconductor switch is connected to a current detection unit to receive an abnormal current detection result provided by the current detection unit. If the current detection unit detects an abnormal current and disconnects the power device from the power system, a bypass circuit is formed that bypasses the current detection unit and connects the neutral line to the ground. The control unit determines whether there is an abnormal current flowing in the neutral line based on the current flowing in the bypass circuit, and controls the semiconductor switch according to the determination result to disconnect the bypass circuit or maintain the connection between the neutral line and the ground through the bypass circuit.

15. The abnormal current detection device according to claim 14, characterized in that, The current detection unit is a ground fault detection indicator, which includes a fuse that blows when an abnormal current exceeding a preset fusing current flows in. The ground fault detection indicator transmits abnormal current detection information to the management system and the semiconductor circuit breaker based on the blown fuse. After receiving the abnormal current detection information, the semiconductor circuit breaker switches from an inactive state to an active state.

16. The abnormal current detection device according to claim 15, characterized in that, If the neutral wire is connected to the ground through the fuse due to the replacement of the blown fuse, the ground fault detection indicator sends an inactive signal to the semiconductor circuit breaker. If the inactive signal is received, the semiconductor circuit breaker switches from the active state to the inactive state and sends information to the management system indicating that the power device is properly connected.

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