External power supply connection device and external power supply system

Abstract

To provide an external power source connection device capable of detecting an electric leakage having occurred in an external circuit including an external power source and an electric leakage having occurred in an indoor circuit, and an external power supply system.SOLUTION: An external power source connection device 1 is a connection device that connects an external circuit 9 including an external power source 90 and an indoor circuit 8 to be installed indoors. The external power source connection device includes: an isolation transformer 3 having a primary side terminal 30 to be electrically connected to the external circuit 9 and a secondary side terminal 31 to be electrically connected to the indoor circuit 8; external leak detection means 6 to be electrically connected to the primary side terminal 30 of the isolation transformer 3, the external leak detection means 6 configured to detect an electric leakage having occurred at the external circuit 9; and internal leak detection means 7 to be electrically connected to the secondary side terminal 31 of the isolation transformer 3, the internal leak detection means 7 configured to detect an electric leakage having occurred at the indoor circuit 8. An external power supply system S comprises the external power source connection device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an external power supply connection device that electrically connects an indoor circuit installed indoors to an external power supply, and to an external power supply system that includes the external power supply connection device. [Background technology]

[0002] Conventionally, external power supply systems have been provided that enable power to be supplied to an indoor circuit (indoor circuit) from an external power source separate from the commercial power source when the power supply from the commercial power source to the indoor circuit of a consumer is interrupted, and such external power supply systems incorporate an external power supply connection device that electrically connects the external power source and the indoor circuit.

[0003] Known examples of this type of external power supply connection device include a charging / discharging device, such as that disclosed in Patent Document 1, which electrically connects a storage battery (external power supply) mounted on an electric vehicle or the like to a distribution board included in an indoor circuit and to which a load is connected.

[0004] The charging / discharging device includes a connector to which the storage battery is connected, and a power conversion unit that is connected to the connector and a distribution board and converts the power received from the storage battery via the connector before sending it to the distribution board.By connecting a cable or the like connected to the storage battery to the connector, the power from the storage battery can be supplied to a load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2013 / 051484 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned conventional charging / discharging device, a leakage current interrupter and a ground fault detection unit are provided on the primary side of the power conversion unit, so while it is possible to know when a leakage current has occurred in the circuit (circuit including the storage battery) connected to the primary side of the power conversion unit, it is not possible to know when a leakage current has occurred in the indoor circuit connected to the secondary side of the power conversion unit.

[0007] In view of the above circumstances, an object of the present invention is to provide an external power supply connection device and an external power supply system that can detect leakage current that occurs in an external circuit including an external power supply and leakage current that occurs in an indoor circuit. [Means for solving the problem]

[0008] The external power supply connection device of the present invention comprises: An external power supply connection device that connects an external circuit including an external power supply and an indoor circuit installed indoors, an isolation transformer having a primary terminal electrically connected to the external circuit and a secondary terminal electrically connected to the indoor circuit; an external leakage current detection means electrically connected to the primary terminal of the isolation transformer, the external leakage current detection means detecting a leakage current occurring in the external circuit; an internal leakage detection means electrically connected to the secondary terminal of the isolation transformer, and an internal leakage detection means for detecting a leakage that occurs in the indoor circuit.

[0009] The external power supply connection device having the above configuration is configured such that the external circuit electrically connected to the primary terminal and the indoor circuit electrically connected to the secondary terminal are insulated by the isolation transformer, and leakage current occurring in the external circuit is detected by external leakage current detection means connected to the primary terminal of the isolation transformer, and leakage current occurring in the indoor circuit is detected by internal leakage current detection means connected to the secondary terminal of the isolation transformer.

[0010] In this way, the external power supply connection device having the above configuration is capable of detecting both leakage current occurring in the external circuit and leakage current occurring in the indoor circuit.

[0011] In the external power supply connection device of the present invention, the external leakage current detection means has a primary-side grounding part electrically connected to the ground, The internal leakage detection means may have a secondary side grounding part electrically connected to the ground.

[0012] According to the external power supply connection device having the above configuration, the external leakage detection means is grounded by the primary-side grounding section, so that it is possible to detect a serious leakage current occurring in the external circuit. Similarly, the internal leakage detection means is grounded by the secondary-side grounding section, so that it is possible to detect a serious leakage current occurring in the internal circuit.

[0013] In the external power supply connection device of the present invention, The secondary side ground may be connected to the primary side ground.

[0014] According to the external power supply connection device having the above configuration, the internal leakage current detection means can share the primary side grounding section with the external leakage current detection means, thereby simplifying the structure of the secondary side grounding section of the internal leakage current detection means.

[0015] The external power supply connection device of the present invention comprises: an input unit to which power from the external power supply is input, The input may be configured to receive AC power.

[0016] According to the external power supply connection device having the above configuration, AC power can be supplied to the indoor circuit.

[0017] In the external power supply system of the present invention, Any one of the external power supply connection devices described above; a distribution board included in the indoor circuit; a switching device that can switch between a state in which the external connection device and the distribution board are electrically connected and a state in which the external connection device and the distribution board are electrically disconnected; Equipped with.

[0018] In the external power supply system configured as described above, the external circuit electrically connected to the primary terminal is insulated from the indoor circuit electrically connected to the secondary terminal by the isolation transformer, and it is possible to detect both leakage current occurring in the external circuit and leakage current occurring in the indoor circuit. [Effects of the Invention]

[0019] As described above, the external power supply connection device and the external power supply system of the present invention can provide the excellent effect of being able to detect leakage current occurring in an external circuit including an external power supply and leakage current occurring in an indoor circuit. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of an external power supply system according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining a mechanism for detecting a leakage current occurring in an external circuit by the external leakage current detection means of the external power supply connection device according to the embodiment. [Figure 3] FIG. 3 is a diagram for explaining a mechanism for detecting a ground fault that occurs in an indoor circuit by the external ground fault detection means of the external power supply connection device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An external power supply connection device according to an embodiment of the present invention and an external power supply system including the external power supply connection device will be described below with reference to the accompanying drawings.

[0022] As shown in Figure 1, the external power supply connection device 1 is configured to be switchable between a state in which an indoor circuit 8 installed indoors and an external circuit 9 for supplying power to the indoor circuit 8 are electrically connected, and a state in which the electrical connection between the indoor circuit 8 and the external circuit 9 is disconnected.

[0023] The external power supply connection device 1 is used, for example, in an environment where a commercial power system P is connected to an indoor circuit 8, so that an external circuit 9, which is a power system separate from the commercial power system P, can be connected to the indoor circuit 8 when the power supply from the commercial power system P to the indoor circuit 8 is interrupted due to a power outage or the like.

[0024] Before describing the external power supply connection device 1, the indoor circuit 8 and the external circuit 9 will be described.

[0025] The indoor circuit 8 includes a distribution board 80 to which a load is connected, a switching device 81 that electrically connects the commercial power system P and the distribution board 80, and an indoor electrical circuit 82 that electrically connects the switching device 81 and the external power supply connection device 1.

[0026] A portion of all indoor loads is connected to the distribution board 80.

[0027] The switching device 81 can be switched between an external circuit disconnected state in which the distribution board 80 and the external circuit 9 are electrically disconnected, and an external circuit connected state in which the distribution board 80 and the external circuit 9 are electrically connected.

[0028] In addition, the switching device 81 of this embodiment is configured to electrically connect the distribution board 80 and the commercial power system P when switched to the external circuit disconnected state, and to electrically disconnect the distribution board 80 and the commercial power system P when switched to the external circuit connected state.

[0029] The indoor circuit 8 has two indoor electrical circuits 82. In this embodiment, one of the two indoor electrical circuits 82 is referred to as a first indoor electrical circuit 820, and the other indoor electrical circuit 82 is referred to as a second indoor electrical circuit 821.

[0030] The first indoor electrical circuit 820 is an ungrounded electrical circuit, and the second indoor electrical circuit 821 is a grounded electrical circuit. That is, the grounding method of the indoor circuit 8 is so-called one-side grounding.

[0031] The external circuit 9 has an external power supply 90 that serves as a power source, and an external electrical circuit 91 that electrically connects the external power supply 90 and the external power supply connection device 1.

[0032] The external power source 90 may be configured as a so-called distributed power source. The external power source 90 may be, for example, a mobile power source such as a storage battery mounted on an electric vehicle, or a stationary power source such as a private power generation facility (for example, a solar power generation system). The distributed power source according to this embodiment is a storage battery mounted on an electric vehicle, and the power of the storage battery is converted into AC power and then supplied to the external circuit 91.

[0033] The external circuit 9 has two external electric circuits 91. In this embodiment, one of the two external electric circuits 91 is referred to as a first external electric circuit 910, and the other external electric circuit 91 is referred to as a second external electric circuit 911.

[0034] As shown in Figure 2, the external power supply connection device 1 includes an input unit 2 to which power is input from an external circuit 9, an isolation transformer 3 having a primary terminal 30 electrically connected to the external circuit 9 and a secondary terminal 31 electrically connected to an indoor circuit 8, a primary connection circuit 4 connected to the input unit 2 and the primary terminal 30 of the isolation transformer 3, a secondary connection circuit 5 connected to the secondary terminal 31 of the isolation transformer 3, external leakage current detection means 6 for detecting leakage current that occurs in the external circuit 9, and internal leakage current detection means 7 for detecting leakage current that occurs in the indoor circuit 8.

[0035] In this embodiment, the phenomenon in which current flows outside a circuit (indoor circuit 8 or external circuit 9) is called a ground fault, and a ground fault in which the current flowing from a circuit to the ground is small is called a light ground fault, and a ground fault in which the current flowing from a circuit to the ground is large is called a heavy ground fault. Furthermore, a phenomenon in which current flows when circuits of different phases come into contact and short out is called a short circuit.

[0036] A first external electric circuit 910 and a second external electric circuit 911 can be connected to the input unit 2. To connect the first external electric circuit 910 and the second external electric circuit 911 to the input unit 2, for example, plugs may be attached to the first external electric circuit 910 and the second external electric circuit 911, and the input unit 2 may be configured as a socket so that the plug can be inserted into and removed from this socket.

[0037] The primary terminal 30 of the isolation transformer 3 is connected to the primary core, and the secondary terminal 31 is connected to the secondary core. In addition, since the primary core and secondary core are insulated from each other in the isolation transformer 3, the external circuit 9 electrically connected to the primary terminal 30 and the indoor circuit 8 electrically connected to the secondary terminal 31 are also insulated from each other.

[0038] The isolation transformer 3 of this embodiment has two primary side terminals 30 and two secondary side terminals 31. One of the two primary side terminals 30 (hereinafter referred to as the first primary side terminal 300) is electrically connected to a first external electric circuit 910, and the other of the two primary side terminals 30 (hereinafter referred to as the second primary side terminal 301) is electrically connected to a second external electric circuit 911.

[0039] Furthermore, one of the two secondary terminals 31 (hereinafter referred to as the first secondary terminal 310) is electrically connected to a first indoor electrical circuit 820 of the indoor circuit 8, and the other of the two secondary terminals 31 (hereinafter referred to as the second secondary terminal 311) is electrically connected to a second indoor electrical circuit 821 of the indoor circuit 8.

[0040] The primary side connection circuit 4 has a first primary side connection circuit 40 connected to a first external circuit 910 via an input section 2 and connected to a first primary side terminal 300, and a second primary side connection circuit 41 connected to a second external circuit 911 via an input section 2 and connected to a second primary side terminal 301.

[0041] The secondary side connecting electric circuit 5 has a first secondary side connecting electric circuit 50 connected to the first secondary side terminal 310 and a second secondary side connecting electric circuit 51 connected to the second secondary side terminal 311.

[0042] The external leakage current detection means 6 has a branch connection part 60 electrically connected to the primary side connection circuit 4 and into which the current flowing in the primary side connection circuit 4 flows, a primary side detection part 61 which detects that a leakage current has occurred in the external circuit 9 based on the state of the current flowing from the primary side connection circuit 4 to the branch connection part 60, and a primary side grounding part 62 which electrically connects the primary side detection part 61 to the ground.

[0043] As described above, the branch connection unit 60 is electrically connected to the primary-side connecting electric circuit 4, and therefore the external leakage detection means 6 is electrically connected to the primary-side terminal 30 of the isolation transformer 3 via the primary-side connecting electric circuit 4, and is also electrically connected to the external circuit 9 via the primary-side connecting electric circuit 4 and the input unit 2. In other words, the branch connection unit 60 is connected between the external circuit 9 and the isolation transformer 3.

[0044] The branch connection portion 60 has a first branch portion 600 electrically connected to the first primary side connecting electric circuit 40 and a second branch portion 601 electrically connected to the second primary side connecting electric circuit 41.

[0045] The first branch 600 and the second branch 601 are configured with resistors and are connected in series to each other. The resistors that make up the first branch 600 and the second branch 601 are configured with the same resistance value.

[0046] Therefore, when the electrical circuit is normal, the current flowing through the first primary side connecting electrical circuit 40 and the current flowing through the second primary side connecting electrical circuit 41 are the same magnitude, so the voltages across each resistor are the same, resulting in a balanced state and no current flowing through the primary side detector 61.

[0047] On the other hand, when a leakage current occurs in the electric circuit, a difference occurs between the magnitude of the current flowing through the first primary-side connecting electric circuit 40 and the magnitude of the current flowing through the second primary-side connecting electric circuit 41. As a result, the magnitude of the voltage applied to the resistors constituting the first branch portion 600 and the second branch portion 601 differs, causing an imbalance, and a current flows to the primary-side detection unit 61 through the first branch portion 600 or the second branch portion 601. As a result, the secondary-side detection unit 61 detects that a leakage current has occurred in the external circuit 9.

[0048] The primary side detection unit 61 is configured to receive current from the first branch 600 and the second branch 601, and is capable of detecting the occurrence of a leakage current in the external circuit 9 based on the current received from the first branch 600 and the second branch 601. The primary side detection unit 61 may be configured by, for example, a current detector.

[0049] The primary side grounding section 62 is electrically connected to the primary side detection section 61 and the ground. Therefore, in the external leakage current detection means 6 of this embodiment, the neutral point of the first primary side connecting electric circuit 40 and the second primary side connecting electric circuit 41 is formed by the first branch section 600 and the second branch section 601, and this neutral point is grounded via the primary side detection section 61 and the primary side grounding section 62. In this way, the primary side grounding section 62 is in a state where it grounds the midpoint of the resistor provided between each phase in the primary side connecting electric circuit 4.

[0050] As a result, the external leakage current detection means 6 is configured to be able to detect not only minor leakage current that occurs in the external circuit 9 but also ground faults. The external leakage current detection means 6 may be configured to connect the primary side detection unit 61 to the ground via a grounding resistor (for example, a grounding rod, etc.).

[0051] Here, a mechanism for detecting a leakage current occurring in the external circuit 9 by the external leakage current detection means 6 will be described.

[0052] When no leakage current occurs in the external circuit 9, no current flows to the ground from the first external electric circuit 910 and the second external electric circuit 911, and therefore the resistance R1 of the first external electric circuit 910 to the ground and the resistance R2 of the second external electric circuit 911 to the ground are infinite, as shown in Fig. 2. Note that the resistances R1 and R2 shown in Fig. 2 are shown for the purpose of explanation and do not represent resistors connecting the first external electric circuit 910 to the ground or resistors connecting the second external electric circuit 911 to the ground.

[0053] In this case, the current flowing through the first external electric circuit 910 is the same in magnitude as the current flowing through the second external electric circuit 911, so the voltages applied to the first primary-side connecting electric circuit 40 and the second primary-side connecting electric circuit 41 are equal, resulting in a state of equilibrium and no current flow. The current flows to the primary-side detection unit 61 through the first branch 600, and the current flowing through the second external electric circuit 911 flows to the primary-side detection unit 61 through the second primary-side connecting electric circuit 41 and the second branch 601. The primary-side detection unit 61 determines that no leakage current is occurring in the external circuit 9 while no current is flowing in from either the first branch 600 or the second branch 601.

[0054] On the other hand, if a ground fault occurs in the first external electric circuit 910, the resistance R1 of the first external electric circuit 910 to the ground decreases, and the current flowing through the first external electric circuit 910 flows to the ground before reaching the first primary-side connecting electric circuit 40. At this time, the primary-side detection unit 61 determines that a ground fault has occurred in the first external electric circuit 910 because the current flowing through the first external electric circuit 910 and the current flowing through the second external electric circuit 911 differ in magnitude, disrupting the equilibrium state, and current flows to the primary-side detection unit 61 via the first branch unit 600.

[0055] Furthermore, if a ground fault occurs in the second external electric circuit 911, the resistance R2 of the second external electric circuit 911 to the ground decreases, and the current flowing through the second external electric circuit 911 flows to the ground before reaching the second primary side connecting electric circuit 41. At this time, the primary side detection unit 61 cannot receive current from the second branch unit 601, and therefore determines that a ground fault has occurred in the second external electric circuit 911.

[0056] In this way, the external leakage current detection means 6 is capable of capturing the current flowing in the first primary side connecting circuit 40 and the current flowing in the second primary side connecting circuit 41 when the neutral point (neutral point of the first primary side connecting circuit 40 and the second primary side connecting circuit 41) formed by the first branch section 600 and the second branch section 601 is grounded, and is configured to detect leakage current occurring in the first external circuit 910 or the second external circuit 911 when the balance between the current flowing in the first external circuit 910 and the current flowing in the second external circuit 911 is disrupted.

[0057] The internal leakage current detection means 7 has a conductive connection part 70 that electrically connects the secondary side connection circuit 5 and the indoor circuit 82, a secondary side detection part 71 that detects leakage current that occurs in the indoor circuit 8 based on the current flowing through the secondary side connection circuit 5, and a secondary side grounding part 72 that grounds the conductive connection part 70.

[0058] As described above, the conductive connection part 70 electrically connects the secondary side connecting electric circuit 5 and the indoor electric circuit 82, so that the internal leakage detection means 7 is electrically connected to the secondary side terminal 31 of the isolation transformer 3 via the secondary side connecting electric circuit 5, and is also electrically connected to the indoor electric circuit 82.

[0059] The conductive connection part 70 has a first conductive connection part 700 that is electrically connected to the first secondary side terminal 310 via the first secondary side connecting circuit 50 and is also electrically connected to the first indoor circuit 820, and a second conductive connection part 701 that is electrically connected to the second secondary side terminal 311 via the second secondary side connecting circuit 51 and is also electrically connected to the second indoor circuit 821.

[0060] The secondary-side detection unit 71 may be configured to have, in addition to a detection function of detecting a ground fault in the indoor circuit 8, a cut-off function of disconnecting (cutting off) the indoor circuit 8 when a ground fault in the indoor circuit 8 is detected, and a function of detecting a short circuit that has occurred in the indoor circuit 8. That is, the secondary-side detection unit 71 of this embodiment may be configured by a so-called earth leakage breaker.

[0061] The secondary-side grounding part 72 is connected to the secondary-side connecting electric circuit 5. In this embodiment, the secondary-side grounding part 72 is connected to the second secondary-side connecting electric circuit 51, which is the neutral line part between the isolation transformer 3 and the external leakage detection means 6, and this neutral line part is grounded.

[0062] Furthermore, the secondary side grounding section 72 of this embodiment is connected to the primary side grounding section 62. Therefore, the secondary side grounding section 72 is connected to the grounding means via the primary side grounding section 62. Therefore, in the external power supply connection device 1 of this embodiment, the primary side grounding section 62 of the external leakage current detection means 6 is configured to be shared by the external leakage current detection means 6 and the internal leakage current detection means 7.

[0063] Here, we will explain how the internal leakage detection means 7 detects leakage that occurs in the indoor circuit 8. As described above, the indoor circuit 8 of this embodiment is one-sided grounded, with only the second indoor electric circuit 821 being grounded, so the internal leakage detection means 7 is configured to detect leakage that occurs in only the first indoor electric circuit 820.

[0064] When no leakage current occurs in the indoor circuit 8, no current flows from the first indoor electric circuit 820 to the ground, and therefore the resistance R3 of the first indoor electric circuit 820 to the ground is infinite, as shown in Figure 3. Note that the resistance R3 shown in Figure 3 is also shown for the purpose of explanation, and does not represent a resistor connecting the first indoor electric circuit 820 to the ground.

[0065] If a ground fault occurs in the first indoor electric circuit 820, the resistance R3 of the first indoor electric circuit 820 to the ground decreases, and current is shunted from the first indoor electric circuit 820 to the ground. The current flowing to the ground reaches the primary-side grounding part 62, and then reaches the internal electric leakage detection means 7 via the secondary-side grounding part 72 and the second secondary-side connecting electric circuit 5. When the internal electric leakage detection means 7 receives current from the second secondary-side connecting electric circuit 5, the magnitude of the current flowing through the round-trip electric circuits between the first indoor electric circuit 820 and the second indoor electric circuit 821 differs, and the internal electric leakage detection means 7 detects a ground fault based on the current difference. It is determined that a ground fault has occurred in the first indoor electric circuit 820 of the indoor circuit 8.

[0066] This completes the description of the configuration of the external power supply connection device 1. In this embodiment, the external power supply system S is made up of the external power supply connection device 1, the distribution board 80, and the switching device 81, and the external power supply system S is able to receive power to be supplied to a load from the commercial power system P or the external circuit 9 by switching the switching device 81 to the external circuit disconnected state or the external circuit connected state.

[0067] Next, a description will be given of the operations of the external power connection device 1 and the external power supply system S. In this embodiment, the operations of the external power connection device 1 and the external power supply system S will be described using an environment in which a commercial power system P is connected to the switching device 81 as an example.

[0068] When the switching device 81 is switched to the external circuit disconnection state, if a leakage current occurs in the first indoor circuit 820, current is diverted from the first indoor circuit 820 to the ground, and the secondary side detection unit 71 detects the leakage current through the primary side grounding unit 62, the secondary side grounding unit 72, and the second secondary side connecting circuit 51.

[0069] When the secondary-side detector 71 detects a current that has been diverted from the first indoor electric circuit 820 to the ground, it detects that a ground fault has occurred in the first indoor electric circuit 820.

[0070] Next, when the switching device 81 is switched to the external circuit connection state, if a leakage current occurs in the first external electric circuit 910 and the primary side detection unit 61 receives current only from the second branch 601, the primary side detection unit 61 detects that a leakage current has occurred in the first external electric circuit 910, and if a leakage current occurs in the second external electric circuit 911 and the primary side detection unit 61 receives current only from the first branch 600, the primary side detection unit 61 detects that a leakage current has occurred in the second external electric circuit 911.

[0071] As described above, in the external power supply connection device 1 and the external power supply system S according to this embodiment, the external circuit 9 connected to the primary terminal 30 and the indoor circuit 8 connected to the secondary terminal 31 are insulated from each other by the isolation transformer 3, so that an electrical abnormality occurring in either the external circuit 9 or the indoor circuit 8 is prevented from spreading to the other of the external circuit 9 and the indoor circuit 8.

[0072] In addition, when the internal leakage current detection means 7 detects a leakage current in the indoor circuit 8, it can disconnect the electrical connection between the external power supply connection device 1 and the indoor circuit 8, making it easier to prevent an electrical abnormality that occurs in the indoor circuit 8 from spreading to the external power supply connection device 1 or the external circuit 9.

[0073] Furthermore, the external power supply connection device 1 is configured to insulate the external circuit 9 electrically connected to the primary terminal 30 from the indoor circuit 8 electrically connected to the secondary terminal 31 by the isolation transformer 3, and detect leakage current occurring in the external circuit 9 by the external leakage current detection means 6 connected to the primary terminal 30 of the isolation transformer 3, and detect leakage current occurring in the indoor circuit 8 by the internal leakage current detection means 7. Therefore, the external power supply connection device 1 and the external power supply system S can achieve the excellent effect of being able to detect leakage current occurring in both the external circuit 9 and the indoor circuit 8.

[0074] Furthermore, since the external leakage current detection means 6 is grounded by the primary side grounding part 62, it can detect serious leakage current (light ground fault) that occurs in the external circuit 9, and similarly, since the internal leakage current detection means 7 is grounded by the secondary side grounding part 72, it can also detect serious leakage current (heavy ground fault) that occurs in the indoor circuit, thereby increasing safety.

[0075] Furthermore, the internal leakage detection means 7 is configured to share the primary-side grounding part 62 with the external leakage detection means 6, which simplifies the structure of the secondary-side grounding part 72 of the internal leakage detection means 7. Accordingly, the construction work for installing the secondary-side grounding part 72 of the internal leakage detection means 7 can also be simplified, making it easier to introduce the external power supply connection device 1 and the external power supply system S.

[0076] It should be noted that the external power supply connection device and external power supply system according to the present invention are not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the gist of the present invention.

[0077] In the above embodiment, the external power supply system S is configured to supply power from the external circuit 9 to some of the multiple loads (a so-called specific load system), but is not limited to this configuration. For example, the external power supply system S may be configured to supply power from the external circuit 9 to all indoor loads (a so-called full load system). In this case, for example, all indoor loads may be connected to the distribution board 80.

[0078] In the above embodiment, the external leakage current detection means 6 is configured to be able to detect light ground faults and heavy ground faults that occur in the external circuit 9, but is not limited to this configuration. The external leakage current detection means 6 may be configured to detect only light ground faults that occur in the external circuit 9, or to detect only heavy ground faults that occur in the external circuit 9, for example.

[0079] Furthermore, the external leakage current detection means 6 may have a function (shutoff function) of disconnecting the electrical connection between the external power supply connection device 1 and the external circuit 9 when a light ground fault or a heavy ground fault that has occurred in the external circuit 9 is detected. In this way, measures can be taken against a light ground fault or a heavy ground fault that has occurred in the external circuit 9, thereby increasing safety.

[0080] Although not specifically mentioned in the above embodiment, the external leakage current detection means 6 may be configured to include a primary-side leakage current notification unit that notifies the user of a light ground fault or a heavy ground fault in the external circuit 9 when the primary-side detection unit 61 detects such a fault. The primary-side leakage current notification unit may be configured, for example, as an alarm or a warning light. Even in this case, safety is enhanced because measures can be taken to deal with light ground faults or heavy ground faults that occur in the external circuit 9. The primary-side leakage current notification unit may be integrated with the primary-side detection unit 61 or may be separate from the primary-side detection unit 61.

[0081] Although not specifically mentioned in the above embodiment, the external leakage current detection means 6 may include, for example, a short circuit detection means for detecting a short circuit that has occurred in the external circuit 9. In this case, even when the short circuit detection means detects a short circuit that has occurred in the external circuit 9, the primary side leakage current notification unit may be configured to notify that a light ground fault or a heavy ground fault has occurred in the external circuit 9, or the external leakage current detection means 6 may be configured to cut off the electrical connection between the external power supply connection device 1 and the external circuit 9.

[0082] In the above embodiment, the internal leakage current detection means 7 is configured to be able to detect light ground faults and heavy ground faults that occur in the indoor circuit 8, but is not limited to this configuration. The internal leakage current detection means 7 may be configured to detect only light ground faults that occur in the indoor circuit 8, or to detect only heavy ground faults that occur in the indoor circuit 8, for example.

[0083] The internal leakage current detection means 7 in the above embodiment has a function (shut-off function) of disconnecting the electrical connection between the external power supply connection device 1 and the indoor circuit 8 when a leakage current or short circuit that has occurred in the indoor circuit 8 is detected, but it may also be limited to detecting a leakage current or short circuit that has occurred in the indoor circuit 8.

[0084] Although not specifically mentioned in the above embodiment, the internal leakage current detection means 7 may be configured to have a secondary leakage current notification unit that notifies the user of a light ground fault or a heavy ground fault in the external circuit 9 when the secondary side detection unit 71 detects a leakage current or a short circuit in the indoor circuit 8. The secondary side leakage current notification unit may be configured, for example, as an alarm or a warning light. In this way, measures can be taken to deal with a light ground fault or a heavy ground fault in the indoor circuit 8, thereby improving safety. The secondary side leakage current notification unit may be integrated with the secondary side detection unit 71 or may be separate from the secondary side detection unit 71.

[0085] In the above embodiment, it was explained that the internal leakage current detection means 7 may be capable of detecting a short circuit that occurs in the indoor circuit 8, but the internal leakage current detection means 7 does not have to have the function of detecting a short circuit that occurs in the indoor circuit 8. [Explanation of symbols]

[0086] 1...external power supply connection device, 2...input section, 3...insulating transformer, 4...primary side connecting circuit, 5...secondary side connecting circuit, 5...second secondary side connecting circuit, 6...external leakage current detection means, 7...internal leakage current detection means, 8...indoor circuit, 9...external circuit, 30...primary side terminal, 31...secondary side terminal, 40...first primary side connecting circuit, 41...second primary side connecting circuit, 50...first secondary side connecting circuit, 51...second secondary side connecting circuit, 60...branch connection section, 61...primary side detection section, 62...primary side grounding section, 63...current transformer, 64...current transformer, 70...conductive connection section, 71...secondary side detection section section, 72...secondary side grounding section, 80...distribution board, 81...switching device, 82...indoor electric circuit, 90...external power supply, 91...external electric circuit, 300...first primary side terminal, 301...second primary side terminal, 310...first secondary side terminal, 311...second secondary side terminal, 600...first branch section, 601...second branch section, 700...first conductive connection section, 701...second conductive connection section, 820...first indoor electric circuit, 821...second indoor electric circuit, 910...first external electric circuit, 911...second external electric circuit, P...commercial power system, R1, R2, R3...resistor, S...external power supply system

Claims

1. An external power supply connection device that connects an external circuit including an external power supply to an indoor circuit installed indoors in a building, the indoor circuit includes a distribution board to which a load is connected, and a switching device provided in an electric path electrically connecting the commercial power system and the distribution board, and electrically connecting the commercial power system, the distribution board, and the external power supply connection device; the switching device is switchable between an external circuit disconnection state in which the commercial power system and the distribution board are electrically connected and the external circuit is electrically disconnected from the distribution board, and an external circuit connection state in which the commercial power system and the distribution board are electrically disconnected and the external circuit is electrically connected to the distribution board; an isolation transformer having two primary terminals electrically connected to the external circuit and a secondary terminal electrically connected to the switching device; an external leakage current detection means electrically connected to the primary terminal of the isolation transformer, the external leakage current detection means detecting a leakage current occurring in the external circuit; an internal leakage detection means electrically connected to the secondary terminal of the isolation transformer, an internal leakage detection means for detecting a leakage current occurring in the indoor circuit; an input unit to which power from the external power supply is input; a first primary-side connecting circuit electrically connected to the external circuit and one of the primary-side terminals via the input section; a second primary-side connecting electric circuit electrically connected to the external circuit and the other primary-side terminal via the input portion, The external power supply connection device is the input section is provided so as to be exposed to the outdoors so that the external circuit can be connected from outdoors, the first primary-side connecting electric circuit, the second primary-side connecting electric circuit, the insulating transformer, the external leakage detection means, and the internal leakage detection means, which are electrically secondary to the input unit, are installed indoors; The external leakage detection means a branch connection portion having a first branch portion which is a resistor electrically connected to the first primary side connecting electric path and a second branch portion which is a resistor electrically connected to the second primary side connecting electric path and has approximately the same resistance value as the first branch portion, and which constitutes an electrical neutral point between the first primary side connecting electric path and the second primary side connecting electric path; a primary side detector electrically connected to the neutral point; a primary-side grounding unit that electrically connects the primary-side detection unit to the ground, the primary side detection unit detects a current flowing from the neutral point to the ground via the primary side grounding unit; External power connection device.

2. the external leakage current detection means has the primary side grounding part electrically connected to the ground, the internal leakage detection means has a secondary side grounding part electrically connected to the ground; 2. The external power supply connection device according to claim 1.

3. the secondary side grounding portion is connected to the primary side grounding portion; 3. The external power supply connection device according to claim 2.

4. an input unit to which power from the external power supply is input, the input is configured to receive AC power; 4. The external power supply connection device according to claim 1.

5. An external power supply system comprising an external circuit including an external power source, an indoor circuit installed indoors in a building, and an external power supply connection device that electrically connects the external circuit and the indoor circuit, the indoor circuit includes a distribution board to which a load is connected, and a switching device provided in an electric path electrically connecting the commercial power system and the distribution board, and electrically connecting the commercial power system, the distribution board, and the external power supply connection device; the switching device is switchable between an external circuit disconnection state in which the commercial power system and the distribution board are electrically connected and the external circuit is electrically disconnected from the distribution board, and an external circuit connection state in which the commercial power system and the distribution board are electrically disconnected and the external circuit is electrically connected to the distribution board; The external power supply connection device is an isolation transformer having two primary terminals electrically connected to the external circuit and a secondary terminal electrically connected to the switching device; an external leakage current detection means electrically connected to the primary terminal of the isolation transformer, the external leakage current detection means detecting a leakage current occurring in the external circuit; an internal leakage detection means electrically connected to the secondary terminal of the isolation transformer, an internal leakage detection means for detecting a leakage current occurring in the indoor circuit; an input unit to which power from the external power supply is input; a first primary-side connecting circuit electrically connected to the external circuit and one of the primary-side terminals via the input section; a second primary-side connecting electric circuit electrically connected to the external circuit and the other primary-side terminal via the input portion, the input section is provided so as to be exposed to the outdoors so that the external circuit can be connected from outdoors, the first primary-side connecting electric circuit, the second primary-side connecting electric circuit, the insulating transformer, the external leakage detection means, and the internal leakage detection means, which are electrically secondary to the input unit, are installed indoors; The external leakage detection means a branch connection portion having a first branch portion which is a resistor electrically connected to the first primary side connecting electric path and a second branch portion which is a resistor electrically connected to the second primary side connecting electric path and has approximately the same resistance value as the first branch portion, and which constitutes an electrical neutral point between the first primary side connecting electric path and the second primary side connecting electric path; a primary side detector electrically connected to the neutral point; a primary-side grounding unit that electrically connects the primary-side detection unit to the ground, The primary side detection unit detects a current flowing from the neutral point to the ground via the primary side grounding unit.

6. In the power supply system according to claim 5, An external power supply system, wherein the external power supply connection device is the external power supply connection device according to any one of claims 2 to 4.

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