Electricity leakage determining device, circuit breaker, distribution board, and program

Abstract

The objective of the present disclosure is to provide an electricity leakage determining device, a circuit breaker, a distribution board, and a program capable of easily matching the sensor characteristics of each of a plurality of coils for measuring current in order to determine an electricity leakage. An electricity leakage determining device (1) is provided with a first air-core coil (21), a second air-core coil (22), a calculating unit (4), and a determining unit (5). The first air-core coil (21) measures a first current (I1), which is a current flowing through a first electric path (L1). The second air-core coil (22) measures a second current (I2), which is a current flowing through a second electric path (L2). The calculating unit (4) calculates the difference between the first current (I1) and the second current (I2). The determining unit (5) determines whether or not an electricity leakage has occurred on the basis of the difference.

Description

Leakage current detection device, circuit breaker, distribution board, and program

[0001] The present disclosure generally relates to a ground fault determining device, a circuit breaker, a distribution board, and a program. More particularly, the present disclosure relates to a ground fault determining device, a circuit breaker, a distribution board, and a program for determining a ground fault.

[0002] Patent Document 1 discloses a ground fault detection device including an annular core, a coil winding wound around the core, and a fuse. The annular core surrounds two or three electric wires of a single-phase two-wire system or a three-phase three-wire system. The fuse is connected in series with the coil winding, and when a differential current occurs between the currents flowing through the two or three electric wires, an induced current based on the differential current flows through the coil winding, causing the fuse to break.

[0003] In a leakage determination device such as the leakage detection device described in Patent Document 1, a leakage in a circuit may be determined based on the results of measuring the current flowing through each of multiple electric wires in the circuit using different coils. In this case, in order to determine a leakage, it is necessary to match the sensor characteristics of the multiple coils that measure the current.

[0004] Japanese Patent Application Laid-Open No. 2007-263663

[0005] An object of the present disclosure is to provide a leakage current determination device, circuit breaker, distribution board, and program that can easily match the sensor characteristics of each of multiple coils that measure current to determine a leakage current.

[0006] A leakage current determination device according to one aspect of the present disclosure is a leakage current determination device that determines whether a leakage current has occurred in a single-phase circuit having at least a first electric circuit and a second electric circuit. The leakage current determination device according to one aspect of the present disclosure includes a first air core coil, a second air core coil, a calculation unit, and a determination unit. The first air core coil measures a first current that is a current flowing in the first electric circuit. The second air core coil measures a second current that is a current flowing in the second electric circuit. The calculation unit calculates the difference between the first current and the second current. The determination unit determines whether the leakage current has occurred based on the difference.

[0007] A leakage current determination device according to one aspect of the present disclosure is a leakage current determination device that determines whether or not a leakage current has occurred in a three-phase circuit having a first electric circuit, a second electric circuit, and a third electric circuit. The leakage current determination device according to one aspect of the present disclosure includes a first air core coil, a second air core coil, a third air core coil, a calculation unit, and a determination unit. The first air core coil measures a first current that is a current flowing in the first electric circuit. The second air core coil measures a second current that is a current flowing in the second electric circuit. The third air core coil measures a third current that is a current flowing in the third electric circuit. The calculation unit calculates a sum of the first current, the second current, and the third current. The determination unit determines whether or not the leakage current has occurred based on the sum.

[0008] A circuit breaker according to an aspect of the present disclosure includes the above-described electric leakage determination device and a breaker unit, which breaks the circuit when the determination unit determines that the electric leakage has occurred.

[0009] A distribution board according to one aspect of the present disclosure includes a main breaker, a plurality of branch breakers, and the above-described leakage current determination device. The plurality of branch breakers are electrically connected to a secondary terminal of the main breaker. The leakage current determination device determines whether a leakage current has occurred in the circuit of at least one of the main breaker and the plurality of branch breakers.

[0010] A program according to one aspect of the present disclosure causes one or more processors of a computer system to realize the functions of the electric leakage determination device described above.

[0011] FIG. 1 is a block diagram showing a schematic configuration of a leakage determination device according to a first embodiment. FIG. 2 is a plan view of a first air core coil and a second air core coil in the leakage determination device according to the first embodiment. FIG. 3 is a front view of a distribution board in the same embodiment. FIG. 4 is a plan view of a first air core coil and a second air core coil in a leakage determination device according to a first modified example. FIG. 5 is a plan view of a first air core coil and a second air core coil in a leakage determination device according to a second modified example. FIG. 6 is an explanatory diagram illustrating a first connection portion and a second connection portion in a leakage determination device according to a third modified example. FIG. 7 is a perspective view of a first connection portion and a second connection portion in a leakage determination device according to a third modified example. FIG. 8 is an exploded perspective view of a leakage determination device according to another modified example, in which multiple boards are stacked along the thickness direction. FIG. 9 is a block diagram showing a schematic configuration of a leakage determination device according to a second embodiment. FIG. 10 is a plan view of a first air core coil, a second air core coil, and a third air core coil in the leakage determination device according to the same embodiment. FIG. 11 is a plan view of the first air core coil, the second air core coil, and the third air core coil in the leakage determining device of the first modified example.

[0012] The embodiments and modifications described below are merely examples of the present disclosure. The present disclosure is not limited to the embodiments and modifications, and various modifications other than these embodiments and modifications are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure. The drawings described in the following embodiments and modifications are schematic drawings, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0013] (1) First Embodiment (1-1) Overview Hereinafter, an overview of an electric leakage determination device 1 according to a first embodiment will be described with reference to FIG.

[0014] The leakage current determination device 1 according to the first embodiment determines whether a leakage current has occurred in a single-phase circuit C1 having at least a first electric circuit L1 and a second electric circuit L2. In the present disclosure, the term "single-phase" includes, for example, a single-phase two-wire system or a single-phase three-wire system. In the following description, it is assumed that the circuit C1 is a single-phase three-wire system.

[0015] The leakage current determination device 1 of the first embodiment includes a first air core coil 21, a second air core coil 22, a calculation unit 4, and a determination unit 5. The first air core coil 21 measures a first current I1, which is a current flowing in a first electrical circuit L1 of the circuit C1. Similarly, the second air core coil 22 measures a second current I2, which is a current flowing in a second electrical circuit L2 of the circuit C1. The calculation unit 4 calculates the difference between the first current I1 measured by the first air core coil 21 and the second current I2 measured by the second air core coil 22. The determination unit 5 determines whether or not a leakage current has occurred in the circuit C1 based on the difference calculated by the calculation unit 4.

[0016] As described above, in the electric leakage determination device 1 of embodiment 1, the determination unit 5 determines whether or not an electric leakage has occurred in the circuit C1 based on the measurement results of the first air core coil 21 and the second air core coil 22. In short, the electric leakage determination device 1 of embodiment 1 uses the first air core coil 21 and the second air core coil 22 as multiple coils for measuring current to determine an electric leakage. Because each of the first air core coil 21 and the second air core coil 22 does not use a member made of a ferromagnetic material or the like as a core, changes in sensor characteristics due to the shape, material, temperature, or the like of the core do not occur. In other words, in the electric leakage determination device 1 of embodiment 1, differences are unlikely to occur between the sensor characteristics of the first air core coil 21 and the sensor characteristics of the second air core coil 22.

[0017] Therefore, the leakage current determination device 1 of embodiment 1 has the advantage that the sensor characteristics of the first air core coil 21 and the sensor characteristics of the second air core coil 22 can be easily matched. In short, the leakage current determination device 1 of embodiment 1 has the advantage that the sensor characteristics of each of the multiple coils that measure current to determine leakage current can be easily matched. Note that the "sensor characteristics" referred to in this disclosure refer to characteristics that indicate the magnitude of the output of the coils (first air core coil 21 and second air core coil 22) when detecting a magnetic field generated by the current, relative to the current value. In other words, the "sensor characteristics" refer to characteristics that indicate the magnitude of the coil output when the coils (first air core coil 21 and second air core coil 22) detect a magnetic field generated by a current of a predetermined current value.

[0018] (1-2) Detailed Configuration (1-2-1) Electric Leakage Determination Device The detailed configuration of the electric leakage determination device 1 of the first embodiment will be described below with reference to Fig. 1 and Fig. 2. In the following description, unless otherwise specified, the front, back, left, and right of Fig. 2 are defined as the front, back, left, and right of a substrate 6 (described later) of the electric leakage determination device 1, and further, the direction perpendicular to the paper surface of Fig. 2 is defined as the up-down direction of the substrate 6 (front is up), but these directions are not intended to limit the orientation in which the substrate 6 is attached.

[0019] As shown in Figure 1, the leakage current detection device 1 includes a first air core coil 21, a second air core coil 22, a conversion unit 3, a calculation unit 4, a determination unit 5, a substrate 6 (see Figure 2), and a transmission unit 7.

[0020] The earth leakage determination device 1 of the first embodiment is provided in one of a plurality of branch breakers A3 in a distribution board A1 (see FIG. 3 ) described later. That is, the earth leakage determination device 1 of the first embodiment determines whether an earth leakage has occurred in the first electric circuit L1 and the second electric circuit L2 connected to one of the plurality of branch breakers A3. In the following description, it is assumed that there are a plurality of earth leakage determination devices 1, each of which corresponds one-to-one to each of the plurality of branch breakers A3, and determines whether an earth leakage has occurred in the first electric circuit L1 and the second electric circuit L2 connected to the corresponding branch breaker A3.

[0021] In the distribution board A1 of the first embodiment, a single-phase three-wire system is assumed as the power distribution system, and therefore the leakage current determination device 1 measures the current flowing in any two of the electric circuits: the neutral wire of the neutral pole (N phase), the voltage wire of the first voltage pole (L1 phase), and the voltage wire of the second voltage pole (L2 phase), and determines whether a leakage current has occurred in these two electric circuits. That is, the first electric circuit L1 and the second electric circuit L2 are any two of the electric circuits: the neutral wire of the neutral pole (N phase), the voltage wire of the first voltage pole (L1 phase), and the voltage wire of the second voltage pole (L2 phase).

[0022] The first air-core coil 21 measures the first current I1 flowing through the first electrical path L1. The first air-core coil 21 is a coreless air-core coil that does not use a core and is a Rogowski coil that generates an output corresponding to the first current I1 flowing through the first electrical path L1. The first air-core coil 21 outputs a first measurement signal Si1, which is an analog signal including the measurement result of the first current I1, to the conversion unit 3.

[0023] Similarly, the second air core coil 22 measures the second current I2 flowing through the second electrical path L2. The second air core coil 22 is an air core coil without a core, and is a Rogowski coil that generates an output corresponding to the second current I2 flowing through the second electrical path L2. The second air core coil 22 outputs a second measurement signal Si2, which is an analog signal including the measurement result of the second current I2, to the conversion unit 3.

[0024] 2, a first air core coil 21 and a second air core coil 22 are provided on the substrate 6. The first air core coil 21 and the second air core coil 22 are provided on the same substrate 6. This configuration has the effect of being easier to manufacture than when the first air core coil 21 and the second air core coil 22 are provided on different substrates. In other words, there is an advantage in that the first air core coil 21 and the second air core coil 22 can be manufactured efficiently.

[0025] The substrate 6 is a multi-layered printed circuit board formed in an elongated shape extending in the left-right direction. The substrate 6 has a first side 61 extending along a first direction D1 (left-right direction) and a second side 62 extending along a second direction D2 (front-rear direction) intersecting (here, perpendicular to) the first direction D1. In the first embodiment, the first direction D1 is the longitudinal direction of the substrate 6, and the second direction D2 is the lateral direction of the substrate 6.

[0026] The substrate 6 is provided with a through hole 63 and a through hole 64 that penetrate in the thickness direction. The center of the through hole 63 and the center of the through hole 64 are provided at different positions when viewed from each of the first direction D1 and the second direction D2.

[0027] The first air core coil 21 is formed around a through hole 63 in the substrate 6. The second air core coil 22 is formed around a through hole 64 in the substrate 6. Each of the first air core coil 21 and the second air core coil 22 is a substrate-mounted Rogowski coil, that is, formed by providing wiring wound in the thickness direction of the substrate 6 on the substrate 6 (not shown in FIG. 2 ). Each of the first air core coil 21 and the second air core coil 22 has a circular ring shape when viewed from the thickness direction of the substrate 6.

[0028] The through hole 63 has a shape that allows the first electrical circuit L1 to pass therethrough. Similarly, the through hole 64 has a shape that allows the second electrical circuit L2 to pass therethrough. The substrate 6 is attached to the branch breaker A3 corresponding to the earth leakage detection device 1 so that the first electrical circuit L1 passes through the through hole 63 and the second electrical circuit L2 passes through the through hole 64. In other words, the first air core coil 21 generates an output corresponding to the first current I1 passing through the through hole 63, and the second air core coil 22 generates an output corresponding to the second current I2 passing through the through hole 64.

[0029] As shown in FIG. 2 , the center of the first air core coil 21 and the center of the second air core coil 22 are located at different positions when viewed from each of the first direction D1 and the second direction D2. The “center of the first air core coil 21” here refers to the center of the area occupied by the first air core coil 21 when viewed from the thickness direction of the substrate 6, and more specifically, the center of the annular-shaped first air core coil 21 when viewed from the thickness direction of the substrate 6. Similarly, the “center of the second air core coil 22” here refers to the center of the area occupied by the second air core coil 22 when viewed from the thickness direction of the substrate 6, and more specifically, the center of the annular-shaped second air core coil 22 when viewed from the thickness direction of the substrate 6. This configuration allows the number of turns of the first air core coil 21 and the second air core coil 22 to be increased, thereby improving the measurement accuracy of the first air core coil 21 and the second air core coil 22. This has the advantage of improving the accuracy with which the leakage current detection device 1 determines a leakage current.

[0030] In the first embodiment, the substrate 6 in each of the multiple electric leakage determination devices 1 is a single substrate. That is, in the first embodiment, the multiple electric leakage determination devices 1 share the substrate 6, and the single substrate 6 is attached to the multiple branch breakers A3 corresponding to each of the multiple electric leakage determination devices 1. The substrate 6 in the first embodiment is provided with multiple through holes 63 and multiple through holes 64. The multiple through holes 63 are arranged side by side in the first direction D1. Similarly, the multiple through holes 64 are arranged side by side in the first direction D1. Furthermore, the centers of the multiple through holes 63 and the multiple through holes 64 are located at different positions from each other when viewed from the first direction D1 and the second direction D2. The substrate 6 in the first embodiment is attached so that the first electric circuit L1 in each of the multiple branch breakers A3 passes through one of the multiple through holes 63, and the second electric circuit L2 in each of the multiple branch breakers A3 passes through one of the multiple through holes 64.

[0031] The first air core coil 21 in each of the plurality of electric leakage determination devices 1 corresponds one-to-one to the plurality of through holes 63 and is formed around the corresponding through hole 63. Similarly, the second air core coil 22 in each of the plurality of electric leakage determination devices 1 corresponds one-to-one to the plurality of through holes 64 and is formed around the corresponding through hole 64.

[0032] The converter 3 converts the input analog signal into a digital signal. As shown in FIG. 2 , one converter 3 in the first embodiment is provided for each pair of the first air core coil 21 and the second air core coil 22. The converter 3 is configured as a single integrated circuit (e.g., an application-specific integrated circuit (ASIC)). The converter 3 is provided on a substrate 6. In the first embodiment, a first terminal of the converter 3 is electrically connected to the positive electrode of the first air core coil 21, and a second terminal of the converter 3 is electrically connected to the negative electrode of the first air core coil 21. Similarly, a third terminal of the converter 3 is electrically connected to the positive electrode of the second air core coil 22, and a fourth terminal of the converter 3 is electrically connected to the negative electrode of the second air core coil 22. The converter 3 alternately acquires a first measurement signal Si1 input from the first air core coil 21 and a second measurement signal Si2 input from the second air core coil 22 in a time-division manner.

[0033] The converter 3 digitally converts each of the first measurement signal Si1 input from the first air core coil 21 and the second measurement signal Si2 input from the second air core coil 22. That is, the first measurement signal Si1 input from the first air core coil 21 and the second measurement signal Si2 input from the second air core coil 22 are each digitally converted by the same converter 3. This configuration makes it possible to prevent a difference from occurring between the digitally converted output of the first air core coil 21 and the digitally converted output of the second air core coil 22. Therefore, the electric leakage determination device 1 of embodiment 1 has the advantage of being able to accurately determine an electric leakage.

[0034] More specifically, the converter 3 amplifies each of the first and second measurement signals Si1 and Si2, converts the amplified first and second measurement signals Si1 and Si2 into digital signals, and outputs the digitally converted first and second measurement signals Si1 and Si2 to the calculator 4.

[0035] The calculator 4 calculates the difference between the first current I1 and the second current I2 based on the first measurement signal Si1 and the second measurement signal Si2 that have been digitally converted by the converter 3. That is, the calculator 4 calculates the difference between the first current I1 and the second current I2 based on the first measurement signal Si1 and the second measurement signal Si2 input from the converter 3. More specifically, the calculator 4 calculates the current value of the first current I1 and the current value of the second current I2 based on the first measurement signal Si1 and the second measurement signal Si2 input from the converter 3, and calculates the difference between the current value of the first current I1 and the current value of the second current I2.

[0036] Specifically, the calculation unit 4 integrates each of the first measurement signal Si1 and the second measurement signal Si2 input from the conversion unit 3. The first measurement signal Si1 output from the first air core coil 21 indicates a value obtained by differentiating the current value of the first current I1, and the second measurement signal Si2 output from the second air core coil 22 indicates a value obtained by differentiating the current value of the second current I2. Therefore, the calculation unit 4 generates a digital signal indicating the current value of the first current I1 by integrating the first measurement signal Si1 converted into digital form by the conversion unit 3. Similarly, the calculation unit 4 generates a digital signal indicating the current value of the second current I2 by integrating the second measurement signal Si2 converted into digital form by the conversion unit 3. The calculation unit 4 calculates the difference between the instantaneous current values ​​of the first current I1 and the second current I2 based on the digital signals indicating the current values ​​of the first current I1 and the second current I2, and generates data indicating the calculated difference. The calculation unit 4 outputs data indicating the calculated difference to the determination unit 5 as a power signal.

[0037] The determination unit 5 determines whether or not a leakage current has occurred in the circuit C1 based on the difference between the first current I1 and the second current I2 calculated by the calculation unit 4. More specifically, the determination unit 5 compares the difference between the instantaneous value of the first current I1 and the instantaneous value of the second current I2 with a preset tolerance range. The determination unit 5 then determines that a leakage current has occurred in the circuit C1 if the difference is outside the tolerance range, and determines that a leakage current has not occurred in the circuit C1 if the difference is within the tolerance range. The determination unit 5 in the first embodiment outputs the determination result to the transmission unit 7 and a tripping control unit 93 (see FIG. 1 ) of the circuit breaker 10, which will be described later.

[0038] The transmitter 7 transmits the determination result of the determination unit 5 to the external device X1. The transmitter 7 has a function of communicating with the external device X1. In the first embodiment, the external device X1 displays the determination result of the determination unit 5 on the display unit X2. The external device X1 may also output the determination result of the determination unit 5 as audio. The external device X1 is, for example, a controller configured to control devices compatible with a Home Energy Management System (HEMS) (hereinafter referred to as HEMS-compatible devices). The HEMS-compatible devices referred to here are devices whose power consumption is to be managed, and include, for example, smart meters, solar power generation devices, power storage devices, fuel cells, electric vehicles, air conditioners, lighting fixtures, hot water heaters, refrigerators, and television sets. Note that the HEMS-compatible devices are not limited to these devices.

[0039] The communication method between the transmitter 7 and the external device X1 may be wireless communication using radio waves as a medium, such as a specified low-power radio station (a radio station that does not require a license) in the 920 MHz band, ZigBee (registered trademark), Bluetooth (registered trademark), etc. The communication method between the transmitter 7 and the external device X1 may also be wired communication such as a wired local area network (LAN).

[0040] The leakage current determination device 1 preferably includes a computer system. In the computer system, a processor such as a CPU or MPU reads and executes a program stored in memory, thereby realizing the functions of the calculation unit 4 and the determination unit 5. The computer system includes a processor that operates according to the program as its main hardware component. The type of processor is not important as long as it can realize the function by executing the program. The processor is composed of one or more electronic circuits, including an IC or LSI. While the terms IC and LSI are used here, the term may be changed depending on the degree of integration, and may also be called a system LSI, VLSI, or ULSI. Field programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, or reconfigurable logic devices that can reconfigure the connections within the LSI or set up circuit partitions within the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated on a single chip or provided on multiple chips. Multiple chips may be integrated into a single device or provided on multiple devices.

[0041] (1-2-2) Circuit Breaker Hereinafter, a detailed configuration of the circuit breaker 10 of the first embodiment will be described with reference to FIG.

[0042] As shown in FIG. 1 , the circuit breaker 10 includes the above-described earth leakage determining device 1 , a breaker unit 91 , an operation unit 92 , and a breaker control unit 93 .

[0043] The interrupter 91 interrupts the circuit C1 when the operating unit 92 is operated. More specifically, when the operating unit 92 is operated, the interrupter 91 forcibly opens a contact 911 inserted in the first electrical circuit L1 and a contact 912 inserted in the second electrical circuit L2, thereby interrupting the circuit C1.

[0044] Furthermore, the interrupter 91 interrupts the circuit C1 based on the control content of the interrupter control unit 93. The interrupter control unit 93 controls whether the interrupter 91 interrupts the circuit C1 based on the determination result input from the determination unit 5 of the electric leakage determination device 1. The interrupter control unit 93 controls the interrupter 91 to interrupt the circuit C1 when the determination unit 5 determines that an electric leakage has occurred in the circuit C1. In other words, the interrupter 91 interrupts the circuit C1 when the determination unit 5 determines that an electric leakage has occurred in the circuit C1.

[0045] (1-2-3) Distribution Board Below, a detailed configuration of the distribution board A1 of embodiment 1 will be described with reference to FIG. 3. Note that in embodiment 1, a case where the distribution board A1 is used in a detached house is illustrated as an example, but the present invention is not limited to this example. The distribution board A1 may also be used in each dwelling unit of an apartment building, an office, a store, etc. Furthermore, in the following description, unless otherwise specified, the top, bottom, left, and right of FIG. 3 are defined as the top, bottom, left, and right of the distribution board A1, and further, the direction perpendicular to the plane of FIG. 3 is defined as the front-to-rear direction of the distribution board A1 (front is the front), but these directions are not intended to limit the orientation in which the distribution board A1 is installed.

[0046] As shown in FIG. 3, the distribution board A1 includes a main breaker A2, a plurality of branch breakers A3, a plurality of earth leakage determining devices 1, and a cabinet A4.

[0047] The cabinet A4 is made of, for example, synthetic resin, and is formed in a box shape with an open front as shown in Fig. 3, and is attached to the wall of a house or the like. The cabinet A4 has a space for accommodating at least the main breaker A2, the plurality of branch breakers A3, and the earth leakage detection device 1. An outer cover A5 is attached to the cabinet A4, and is movable between a position that closes the front of the cabinet A4 and a position that opens it.

[0048] The main breaker A2 has a primary terminal and a secondary terminal. The primary terminal of the main breaker A2 is electrically connected to a single-phase three-wire service line of the system power supply (commercial power supply). The secondary terminal of the main breaker A2 is electrically connected to each of the multiple branch breakers A3 via three conductive bars.

[0049] In the distribution board A1 of embodiment 1, a single-phase three-wire system is assumed as the power distribution method, and therefore the three conductive bars are used as a conductive bar for the neutral pole (N phase), a conductive bar for the first voltage pole (L1 phase), and a conductive bar for the second voltage pole (L2 phase).

[0050] The branch breakers A3 are divided into upper and lower sections, with multiple units (11 units in the example of FIG. 3 ) arranged side by side in the left-right direction. Each of the branch breakers A3 has a primary terminal and a secondary terminal. The primary terminal of each of the branch breakers A3 is electrically connected to the secondary terminal of the main breaker A2 via any two of the three conductive bars. More specifically, the branch breakers A3 connected to the neutral pole and the first voltage pole are electrically connected to the secondary terminal of the main breaker A2 via the neutral pole conductive bar and the first voltage pole conductive bar. The branch breakers A3 connected to the neutral pole and the second voltage pole are electrically connected to the secondary terminal of the main breaker A2 via the neutral pole conductive bar and the second voltage pole conductive bar. The branch breakers A3 connected to the first voltage pole and the second voltage pole are electrically connected to the secondary terminal of the main breaker A2 via the first voltage pole conductive bar and the second voltage pole conductive bar.

[0051] A plurality of electrical circuits are electrically connected to the secondary terminals of each of the plurality of branch breakers A3. One or more loads, such as lighting fixtures, hot water supply equipment, and wiring fixtures, such as electrical outlets and wall switches, are connected to the electrical circuits connected to the secondary terminals of each of the plurality of branch breakers A3.

[0052] In the first embodiment, the plurality of leakage current determination devices 1 are associated one-to-one with the plurality of branch breakers A3. Each of the plurality of leakage current determination devices 1 determines whether or not a leakage current has occurred in the circuit C1 of the corresponding branch breaker A3. More specifically, each of the plurality of leakage current determination devices 1 determines whether or not a leakage current has occurred in the circuit C1 that electrically connects the main breaker A2 and a load (electrical path) connected to the corresponding branch breaker A3 via the corresponding branch breaker A3. That is, the circuit C1 includes any two of the three conductive bars that electrically connect the corresponding branch breaker A3 to the main breaker A2 and an electrical path connected to the secondary terminal of the corresponding branch breaker A3.

[0053] First, we will explain the earth leakage determination device 1 associated with the branch breaker A3 connected to the neutral pole and the first voltage pole. The earth leakage determination device 1 is mounted on the distribution board A1 so that the first air core coil 21 measures the current flowing through the conductive bar of the neutral pole and the second air core coil 22 measures the current flowing through the conductive bar of the first voltage pole. More specifically, the circuit board 6 of the earth leakage determination device 1 is attached to the branch breaker A3 associated with the earth leakage determination device 1 so that the conductive bar of the neutral pole passes through the through-hole 63 and the conductive bar of the first voltage pole passes through the through-hole 64. The determination unit 5 of the earth leakage determination device 1 determines whether an earth leakage has occurred in the circuit C1 based on the difference between the current flowing through the conductive bar of the neutral pole and the current flowing through the conductive bar of the first voltage pole. In short, in the above-described earth leakage determination device 1, the first electric circuit L1 is the neutral wire of a single-phase three-wire system, and the second electric circuit L2 is one of the two voltage wires of the single-phase three-wire system (specifically, the L1-phase voltage wire). This configuration has the advantage that when determining whether or not there is an earth leakage in the current flowing between the neutral wire and the voltage wire of the single-phase three-wire system, the sensor characteristics of each of the multiple coils can be easily matched.

[0054] Next, we will explain the earth leakage determination device 1 associated with the branch breaker A3 connected to the neutral pole and the second voltage pole. The earth leakage determination device 1 is provided on the distribution board A1 so that the first air core coil 21 measures the current flowing through the conductive bar of the neutral pole, and the second air core coil 22 measures the current flowing through the conductive bar of the second voltage pole. More specifically, the circuit board 6 of the earth leakage determination device 1 is attached to the branch breaker A3 associated with the earth leakage determination device 1 so that the conductive bar of the neutral pole passes through the through-hole 63 and the conductive bar of the second voltage pole passes through the through-hole 64. The determination unit 5 of the earth leakage determination device 1 determines whether an earth leakage has occurred in the circuit C1 based on the difference between the current flowing through the conductive bar of the neutral pole and the current flowing through the conductive bar of the second voltage pole. In short, in the above-described earth leakage determination device 1, the first electric circuit L1 is the neutral wire of a single-phase three-wire system, and the second electric circuit L2 is one of the two voltage wires of the single-phase three-wire system (specifically, the L2-phase voltage wire). This configuration has the advantage that when determining whether or not there is an earth leakage in the current flowing between the neutral wire and the voltage wire of the single-phase three-wire system, the sensor characteristics of each of the multiple coils can be easily matched.

[0055] Next, a description will be given of the leakage current determination device 1 associated with the branch breaker A3 connected to the first and second voltage poles. The leakage current determination device 1 is provided on the distribution board A1 so that the first air-core coil 21 measures the current flowing through the conductive bar of the first voltage pole, and the second air-core coil 22 measures the current flowing through the conductive bar of the second voltage pole. More specifically, the circuit board 6 of the leakage current determination device 1 is attached to the branch breaker A3 associated with the leakage current determination device 1 so that the conductive bar of the first voltage pole passes through the through-hole 63 and the conductive bar of the second voltage pole passes through the through-hole 64. The determination unit 5 of the leakage current determination device 1 determines whether or not a leakage current has occurred in the circuit C1 based on the difference between the current flowing through the conductive bar of the first voltage pole and the current flowing through the conductive bar of the second voltage pole. In short, in the above-described leakage determination device 1, the first electric circuit L1 is one of the two voltage lines of a single-phase three-wire system (specifically, the L1-phase voltage line), and the second electric circuit L2 is the other of the two voltage lines (specifically, the L2-phase voltage line). This configuration has the advantage that, when determining whether or not a current flowing between two voltage lines in a single-phase three-wire system is leaking, the sensor characteristics of each of the multiple coils can be easily matched.

[0056] (1-3) Modifications of Embodiment 1 The above-described embodiment 1 is merely one of various embodiments of the present disclosure. The above-described embodiment 1 can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. The following modifications may be realized in appropriate combination. The same components as those in the above-described embodiment 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0057] (1-3-1) First Modification of Embodiment 1 In the electric leakage determination device 1 of the above-described embodiment 1, the center of the first air core coil 21 and the center of the second air core coil 22 are disposed at different positions when viewed from each of the first direction D1 and the second direction D2. However, in the electric leakage determination device 1A of the first modification shown in Fig. 4, the center of the first air core coil 21 and the center of the second air core coil 22 are disposed so as to be aligned in the second direction D2.

[0058] The detailed configuration of the electric leakage determining device 1A of the first modified example will be described below.

[0059] The leakage current determining device 1A of the first modified example includes a first air core coil 21A, a second air core coil 22A, a conversion unit 3A, a calculation unit 4, a determination unit 5, a substrate 6A, and a transmission unit 7.

[0060] The substrate 6A is provided with a through hole 63A and a through hole 64A that penetrate through the substrate 6A in the thickness direction. The centers of the through holes 63A and 64A are located at different positions when viewed from the first direction D1, but at the same position when viewed from the second direction D2. In other words, the centers of the through holes 63A and 64A are aligned in the second direction D2.

[0061] The first air core coil 21A is formed around the through hole 63A in the substrate 6A. The second air core coil 22A is formed around the through hole 64A in the substrate 6A. Therefore, the centers of the first air core coil 21A and the second air core coil 22A are formed at different positions when viewed from the first direction D1, but at the same position when viewed from the second direction D2. In other words, the centers of the first air core coil 21A and the second air core coil 22A are formed to be aligned in the second direction D2.

[0062] In the electric leakage determination device 1A of the first modification, similar to the electric leakage determination device 1 of the first embodiment, the substrate 6A in each of the plurality of electric leakage determination devices 1A is a single substrate. That is, in the first modification, each of the plurality of electric leakage determination devices 1A shares the substrate 6A, and the substrate 6A is provided with a plurality of through holes 63A and a plurality of through holes 64A. The plurality of through holes 63A are arranged side by side in the first direction D1. Similarly, the plurality of through holes 64A are arranged side by side in the first direction D1. Furthermore, the center of each of the plurality of through holes 63A and the center of each of the plurality of through holes 64A are located at the same position as viewed from the second direction D2. The substrate 6A of the first modification 1 is attached so that the first electric circuit L1 and the second electric circuit L2 connected to each of the plurality of branch breakers A3 pass through the corresponding through holes 63A and 64A.

[0063] The conversion unit 3A of the first modified example is provided for each pair of the first air core coil 21A and the second air core coil 22A in the electric leakage determination device 1A (hereinafter referred to as the left electric leakage determination device 1A) and the first air core coil 21 and the second air core coil 22 in the electric leakage determination device 1A adjacent to the above-mentioned electric leakage determination device 1A (hereinafter referred to as the right electric leakage determination device 1A). In the first modified example, the first terminal of the conversion unit 3A is electrically connected to the positive electrode of the first air core coil 21 in the left electric leakage determination device 1A, and the second terminal of the conversion unit 3A is electrically connected to the negative electrode of the first air core coil 21 in the left electric leakage determination device 1A. Similarly, in the first modified example, the third terminal of the conversion unit 3A is electrically connected to the positive electrode of the second air core coil 22 in the left-side electric leakage determination device 1A, and the fourth terminal of the conversion unit 3A is electrically connected to the negative electrode of the second air core coil 22A in the left-side electric leakage determination device 1A. Furthermore, the fifth terminal of the conversion unit 3A is electrically connected to the positive electrode of the first air core coil 21A in the right-side electric leakage determination device 1A, and the sixth terminal of the conversion unit 3A is electrically connected to the negative electrode of the first air core coil 21A in the right-side electric leakage determination device 1A. Similarly, in the first modified example, the seventh terminal of the conversion unit 3A is electrically connected to the positive electrode of the second air core coil 22 in the right-side electric leakage determination device 1A, and the eighth terminal of the conversion unit 3A is electrically connected to the negative electrode of the second air core coil 22 in the right-side electric leakage determination device 1A. In addition, the conversion unit 3A alternately acquires, in a time-division manner, a first measurement signal Si1 input from the first air-core coil 21 in each of the left-side leakage current determination device 1A and the right-side leakage current determination device 1, and a second measurement signal Si2 input from the second air-core coil 22A in each of the left-side leakage current determination device 1A and the right-side leakage current determination device 1A.

[0064] That is, in the first modification, two adjacent electric leakage determination devices 1A share the conversion unit 3A. This configuration eliminates the need for each of the two adjacent electric leakage determination devices 1A to have a conversion unit 3A, which has the effect of reducing the number of conversion units 3D. That is, there is an advantage that the configuration of multiple electric leakage determination devices 1A can be simplified and manufacturing costs can be reduced.

[0065] (1-3-2) Second Modification of Embodiment 1 The leakage determination device 1 of the above-described embodiment 1 measures the current flowing in any two of the electric paths: the neutral wire of the neutral pole (N phase), the voltage wire of the first voltage pole (L1 phase), and the voltage wire of the second voltage pole (L2 phase). However, the leakage determination device 1B of the second modification shown in FIG. 5 measures the current flowing in each of the neutral wire of the neutral pole (N phase), the voltage wire of the first voltage pole (L1 phase), and the voltage wire of the second voltage pole (L2 phase).

[0066] The detailed configuration of the electric leakage determining device 1B of the second modified example will be described below.

[0067] The second modified example of the leakage current detection device 1B includes a first air core coil 21B, a second air core coil 22B, a third air core coil 23B, a conversion unit 3B, a calculation unit 4, a determination unit 5, a substrate 6, and a transmission unit 7.

[0068] The first air core coil 21B measures the current flowing in the first electrical circuit L1, which is the neutral conductor of the neutral pole (N phase). Similarly, the second air core coil 22B measures the current flowing in the second electrical circuit L2, which is the voltage conductor of the first voltage pole (L1 phase). Furthermore, the third air core coil 23B measures the current flowing in the third electrical circuit L3, which is the voltage conductor of the second voltage pole (L2 phase).

[0069] The substrate 6B is provided with through holes 63B, 64B, and 65B that penetrate through the substrate 6B in the thickness direction. The centers of the through holes 63B, 64B, and 65B are located at different positions when viewed from the first direction D1, and at the same position when viewed from the second direction D2.

[0070] The first air core coil 21B is formed around the through hole 63B of the substrate 6B. The second air core coil 22B is formed around the through hole 64B of the substrate 6B. The third air core coil 23B is formed around the through hole 65B of the substrate 6B. Therefore, the centers of the first air core coil 21B, the second air core coil 22B, and the third air core coil 23B are located at different positions when viewed from the first direction D1, but at the same position when viewed from the second direction D2. In other words, the centers of the first air core coil 21B, the second air core coil 22B, and the third air core coil 23B are aligned in the second direction D2.

[0071] In the electric leakage determination device 1B of the second modified example, similar to the electric leakage determination device 1 of the first embodiment, the substrate 6B in each of the plurality of electric leakage determination devices 1B is a single substrate. That is, in the second modified example, each of the plurality of electric leakage determination devices 1B shares the substrate 6B, and the substrate 6B is provided with a plurality of through holes 63B, a plurality of through holes 64B, and a plurality of through holes 65B. The plurality of through holes 63B are arranged side by side in the first direction D1. Similarly, the plurality of through holes 64B are arranged side by side in the first direction D1. The plurality of through holes 65B are arranged side by side in the first direction D1. Furthermore, the centers of the plurality of through holes 63B, the centers of the plurality of through holes 64B, and the centers of the plurality of through holes 65B are located at the same position when viewed from the second direction D2. The substrate 6B of the second modified example is mounted so that the first electrical circuit L1, the second electrical circuit L2, and the third electrical circuit L3 connected to each of the multiple branch breakers A3 pass through the corresponding through holes 63B, 64B, and 65B.

[0072] The conversion unit 3 digitally converts each of the first measurement signal input from the first air core coil 21, the second measurement signal input from the second air core coil 22, and the third measurement signal input from the third air core coil 23. In the second modified example, each of two adjacent earth leakage determination devices 1B shares the conversion unit 3B, as in the first modified example. A detailed description of the configuration of the conversion unit 3B will be omitted.

[0073] First, when the earth leakage determination device 1B corresponds to the branch breaker A3 connected to the neutral pole and the first voltage pole, the calculation unit 4 of the second modification calculates the difference between the current flowing in the first electric circuit L1, which is the neutral conductor of the neutral pole (N phase), and the current flowing in the second electric circuit L2, which is the voltage conductor of the first voltage pole (L1 phase), based on the first measurement signal and the second measurement signal converted into digital form by the conversion unit 3B. The determination unit 5 of the second modification determines whether an earth leakage has occurred in the circuit C1 based on the difference calculated by the calculation unit 4. That is, in the above case, the determination unit 5 of the second modification determines whether an earth leakage has occurred in the circuit C1 based on the difference between the current flowing in the conductive bar of the neutral pole and the current flowing in the conductive bar of the first voltage pole.

[0074] Next, when the earth leakage determination device 1B corresponds to the branch breaker A3 connected to the neutral pole and the second voltage pole, the calculation unit 4 of the second modified example calculates the difference between the current flowing in the first electric circuit L1, which is the neutral conductor of the neutral pole (N phase), and the current flowing in the third electric circuit L3, which is the voltage conductor of the second voltage pole (L2 phase), based on the first measurement signal and the third measurement signal converted into digital form by the conversion unit 3B. The determination unit 5 of the second modified example determines whether an earth leakage has occurred in the circuit C1 based on the difference calculated by the calculation unit 4. That is, in the above case, the determination unit 5 of the second modified example determines whether an earth leakage has occurred in the circuit C1 based on the difference between the current flowing in the conductive bar of the neutral pole and the current flowing in the conductive bar of the second voltage pole.

[0075] Furthermore, when the leakage current determination device 1B corresponds to the branch breaker A3 connected to the first voltage pole and the second voltage pole, the calculation unit 4 of the second modification calculates the difference between the current flowing in the second electric circuit L2, which is the voltage line of the first voltage pole (L1 phase), and the current flowing in the third electric circuit L3, which is the voltage line of the second voltage pole (L2 phase), based on the second measurement signal and the third measurement signal converted into digital form by the conversion unit 3B. The determination unit 5 of the second modification determines whether or not a leakage current has occurred in the circuit C1 based on the difference calculated by the calculation unit 4. That is, in the above case, the determination unit 5 of the second modification determines whether or not a leakage current has occurred in the circuit C1 based on the difference between the current flowing in the conductive bar of the first voltage pole and the current flowing in the conductive bar of the second voltage pole.

[0076] (1-3-3) Third Modification of Embodiment 1 The leakage current determination device 1C of the third modification shown in Figures 6 and 7 electrically connects a selected one of the neutral wire L4 of the neutral pole (N phase) and the voltage wire L5 of the first voltage pole (L1 phase) to the first electrical circuit L1.

[0077] The detailed configuration of the electric leakage determination device 1C of the third modified example will be described below.

[0078] The third variant of the leakage current detection device 1C comprises a first air core coil 21, a second air core coil 22, a conversion unit 3, a calculation unit 4, a determination unit 5, a substrate 6, a transmission unit 7, a first connection unit 81, a switching bar 82, and a second connection unit 83.

[0079] The first connection portion 81 electrically connects a selected one of the neutral wire L4 of the neutral pole (N phase) and the voltage wire L5 of the first voltage pole (L1 phase) to the first electric circuit L1. Therefore, the first air core coil 21 of the third modified example measures, as the first current I1, the current flowing through the neutral wire L4 or the voltage wire L5 electrically connected to the first electric circuit L1 by the first connection portion 81.

[0080] More specifically, the first connection portion 81 is interlocked with the switching bar 82 and is configured to be movable between a first position and a second position. When the switching bar 82 is operated, the first connection portion 81 moves from the first position to the second position, or from the second position to the first position. When the first connection portion 81 is located in the first position, as shown in FIG. 6 , the first connection portion 81 electrically connects the neutral conductor L4 of the neutral pole to the first electrical circuit L1 and does not electrically connect the voltage conductor L5 of the first voltage pole to the first electrical circuit L1. When the first connection portion 81 is located in the first position, the first air core coil 21 of the third modified example measures the current flowing through the neutral conductor L4 as the first current I1.

[0081] On the other hand, when the first connection portion 81 is located in the second position, the voltage wire L5 of the first voltage pole is electrically connected to the first electric circuit L1, and the neutral wire L4 of the neutral pole is not electrically connected to the first electric circuit L1, as shown in Fig. 7. When the first connection portion 81 is located in the second position, the first air core coil 21 of the third modified example measures the current flowing in the first electric circuit L1 as the first current I1.

[0082] The second connection portion 83 electrically connects the voltage line L6 of the second voltage pole (L2 phase) to the second electrical path L2. Therefore, the second air core coil 22 of the third modified example measures the current flowing through the voltage line L6 of the second voltage pole (L2 phase) as the first current I1.

[0083] As described above, when the first connection part 81 is located at the first position, the calculation part 4 calculates the difference between the current flowing in the neutral wire L4 and the current flowing in the voltage line L6 of the second voltage pole (L2 phase), and the determination part 5 determines whether or not a leakage current has occurred in the circuit C1 based on the difference calculated by the calculation part 4. On the other hand, when the first connection part 81 is located at the second position, the calculation part 4 calculates the difference between the current flowing in the voltage line L5 of the first voltage pole (L1 phase) and the current flowing in the voltage line L6 of the second voltage pole (L2 phase), and the determination part 5 determines whether or not a leakage current has occurred in the circuit C1 based on the difference calculated by the calculation part 4.

[0084] (1-3-4) Other Modifications of Embodiment 1 Other modifications of the above-described embodiment 1 are listed below. The following modifications may be realized in appropriate combination. Furthermore, functions similar to those of the electric leakage determination device 1 according to the above-described embodiment 1 may be embodied as a computer program, a non-transitory recording medium on which a program is recorded, or the like. The program according to one aspect is a program that causes one or more processors of a computer system to realize the functions of the electric leakage determination device 1 according to the above-described embodiment 1.

[0085] As shown in FIG. 8 , the leakage current detection device 1 may include a plurality of substrates 6, which may be stacked along the thickness direction (vertical direction) of each of the substrates 6. In this case, the first air core coils 21 on each of the substrates 6 are aligned along the thickness direction, and the second air core coils 22 on each of the substrates 6 are aligned along the thickness direction. More specifically, in the above configuration, the first terminal of the conversion unit 3 is electrically connected to the positive electrode of the topmost first air core coil 21 among the plurality of first air core coils 21 aligned along the thickness direction, and the second terminal of the conversion unit 3 is electrically connected to the positive electrode of the bottommost first air core coil 21 among the plurality of first air core coils 21 aligned along the thickness direction. Furthermore, the negative electrode of each of the plurality of first air core coils 21, excluding both the topmost and bottommost first air core coils 21, is electrically connected to the positive electrode of the first air core coil 21 aligned below it. Similarly, the third terminal of the conversion unit 3 is electrically connected to the positive electrode of the second air core coil 22 that is arranged at the top of the plurality of second air core coils 22 lined up along the thickness direction, and the fourth terminal of the conversion unit 3 is electrically connected to the positive electrode of the second air core coil 22 that is arranged at the bottom of the plurality of second air core coils 22 lined up along the thickness direction. The negative electrode of each of the plurality of second air core coils 22, excluding both the topmost and bottommost second air core coils 22, is electrically connected to the positive electrode of the second air core coil 22 lined up below it. The conversion unit 3 alternately acquires the first measurement signals Si1 input from the plurality of first air core coils 21 and the second measurement signals Si2 input from the plurality of second air core coils 22 in a time-division manner.

[0086] The above configuration increases the output of the first air core coil 21 and the second air core coil 22, thereby increasing the sensitivity of the first air core coil 21 and the second air core coil 22. In other words, it improves the measurement accuracy of the first air core coil 21 and the second air core coil 22. This has the advantage of improving the accuracy with which the leakage current detection device 1 determines a leakage current.

[0087] Furthermore, in the leakage detection device 1, the positive electrode of the first air core coil 21 may be electrically connected to the positive electrode of the second air core coil 22, and the negative electrode of the first air core coil 21 may be electrically connected to the negative electrode of the second air core coil 22. In the above configuration, the first terminal of the conversion unit 3 is electrically connected to both the positive electrode of the first air core coil 21 and the positive electrode of the second air core coil 22, and the second terminal of the conversion unit 3 is electrically connected to both the negative electrode of the first air core coil 21 and the negative electrode of the second air core coil 22. As a result, when a leakage current occurs in the circuit C1, i.e., when there is a difference between the current value of the first current I1 and the current value of the second current I2, the conversion unit 3 receives an electrical signal from the first air core coil 21 or the second air core coil 22 and converts the input electrical signal into a digital signal. The calculation unit 4 calculates the difference between the first current I1 and the second current I2 based on the electrical signal digitally converted by the conversion unit 3. According to the above configuration, it is possible to reduce the number of signals that are converted by the conversion unit 3. In other words, there is an advantage in that the load on the conversion unit 3 can be reduced.

[0088] Although the first embodiment described above assumes that the circuit C1 is a single-phase, three-wire circuit, the circuit C1 may also be a single-phase, two-wire circuit. That is, the first electrical path L1 is a voltage line (more specifically, an L-phase voltage line) of the single-phase, two-wire system, and the second electrical path L2 is a neutral line of the single-phase, two-wire system. This configuration has the advantage that, when determining whether or not a current is leaking between the neutral line and the voltage line of the single-phase, three-wire system, the sensor characteristics of each of the multiple coils can be easily matched.

[0089] In the first embodiment described above, each of the plurality of leakage current determination devices 1 determines whether or not a leakage current has occurred in the circuit C1 of the corresponding branch breaker A3 among the plurality of branch breakers A3. However, the plurality of leakage current determination devices 1 may be associated one-to-one with one or more of the plurality of branch breakers A3, and each of the plurality of leakage current determination devices 1 may determine whether or not a leakage current has occurred in the circuit C1 of the corresponding branch breaker A3. Alternatively, the leakage current determination device 1 may determine whether or not a leakage current has occurred in the circuit C1 of the main breaker A2. In other words, the leakage current determination device 1 may determine whether or not a leakage current has occurred in the circuit C1 of at least one of the main breaker A2 and the plurality of branch breakers A3.

[0090] In the first embodiment, the substrate 6 in each of the plurality of electric leakage determination devices 1 is a single substrate, but may be an individual substrate. That is, the plurality of electric leakage determination devices 1D do not need to share the substrate 6D.

[0091] (2) Second Embodiment (2-1) Overview An overview of an electric leakage determination device 1D according to a second embodiment will be described below with reference to Fig. 9. Components similar to those in the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0092] The leakage current determination device 1D according to the second embodiment determines whether a leakage current has occurred in a three-phase circuit CA1 having a first electric circuit LA1, a second electric circuit LA2, and a third electric circuit LA3. In the present disclosure, the term "three-phase" includes, for example, a three-phase, three-wire system. In the following description, it is assumed that the circuit CA1 is a three-phase, three-wire system.

[0093] The leakage current determination device 1D of the second embodiment includes a first air core coil 21D, a second air core coil 22D, a calculation unit 4D, and a determination unit 5D. The first air core coil 21D measures a first current IA1, which is the current flowing in the first electrical circuit LA1 of the circuit CA1. Similarly, the second air core coil 22 measures a second current IA2, which is the current flowing in the second electrical circuit LA2 of the circuit CA1. The third air core coil 23 measures a third current IA3, which is the current flowing in the third electrical circuit LA3 of the circuit CA1. The calculation unit 4D calculates the sum of the first current IA1 measured by the first air core coil 21D, the second current IA2 measured by the second air core coil 22D, and the third current IA3 measured by the third air core coil 23D. The determination unit 5D determines whether or not a leakage current has occurred in the circuit CA1 based on the sum calculated by the calculation unit 4D.

[0094] As described above, in the electric leakage determination device 1D of the second embodiment, the determination unit 5D determines whether an electric leakage has occurred in the circuit CA1 based on the measurement results of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D. In other words, the electric leakage determination device 1D of the second embodiment uses the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D as the coils for measuring current to determine an electric leakage. Because each of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D does not use a ferromagnetic material or other material as a core, changes in sensor characteristics due to the shape, material, temperature, or the like of the core do not occur. In other words, the electric leakage determination device 1D of the second embodiment can suppress differences in the sensor characteristics of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D.

[0095] As described above, the electric leakage determination device 1D of the second embodiment has the advantage that it is possible to easily match the sensor characteristics of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D. In short, the electric leakage determination device 1D of the second embodiment has the advantage that it is possible to easily match the sensor characteristics of each of the multiple coils that measure current to determine an electric leakage.

[0096] (2-2) Detailed Configuration (2-2-1) Electric Leakage Determining Device Hereinafter, the detailed configuration of the electric leakage determining device 1D of the second embodiment will be described with reference to FIGS. 9 and 10. FIG.

[0097] As shown in FIG. 9, the leakage determining device 1D includes a first air core coil 21D, a second air core coil 22D, a conversion unit 3D, a calculation unit 4D, a determination unit 5D, a substrate 6D, and a transmission unit 7.

[0098] The electric leakage determination device 1D of the second embodiment is provided in at least one of the main breaker A2 and the plurality of branch breakers A3 of the distribution board A1 (see FIG. 3 ). That is, the electric leakage determination device 1D of the second embodiment determines whether an electric leakage has occurred in the first electric circuit LA1, the second electric circuit LA2, and the third electric circuit LA3 connected to at least one of the main breaker A2 and the plurality of branch breakers A3.

[0099] The first air-core coil 21D measures a first current IA1 flowing through the first electrical circuit LA1. The first air-core coil 21D is a coreless air-core coil that does not use a core and is a Rogowski coil that generates an output corresponding to the first current IA1 flowing through the first electrical circuit LA1. The first air-core coil 21D outputs a first measurement signal Si1, which is an analog signal including the measurement result of the first current IA1, to the conversion unit 3D.

[0100] Similarly, the second air-core coil 22D measures the second current IA2 flowing through the second electrical circuit LA2. The second air-core coil 22D is a coreless air-core coil that does not use a core and is a Rogowski coil that generates an output corresponding to the second current IA2 flowing through the second electrical circuit LA2. The second air-core coil 22D outputs a second measurement signal Si2, which is an analog signal including the measurement result of the second current IA2, to the conversion unit 3D.

[0101] Furthermore, the third air-core coil 23D measures the third current IA3 flowing through the third electrical circuit LA3. The third air-core coil 23D is a coreless air-core coil that does not use a core and is a Rogowski coil that generates an output corresponding to the third current IA3 flowing through the third electrical circuit LA3. The third air-core coil 23D outputs a third measurement signal Si3, which is an analog signal including the measurement result of the third current IA3, to the conversion unit 3D.

[0102] As shown in Fig. 10, a first air core coil 21D, a second air core coil 22D, and a third air core coil 23D are provided on a substrate 6D. The first air core coil 21D, the second air core coil 22D, and the third air core coil 23D are provided on the same substrate 6D. This configuration has the advantage of being easier to manufacture than when the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D are provided on different substrates. In other words, there is an advantage in that the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D can be manufactured efficiently.

[0103] The substrate 6D is a multi-layered printed circuit board formed in an elongated shape extending in the left-right direction. The substrate 6D has a first side 61 extending along a first direction D1 (left-right direction) and a second side 62 extending along a second direction D2 (front-rear direction) intersecting (here, perpendicular to) the first direction D1. In the second embodiment, the first direction D1 is the longitudinal direction of the substrate 6D, and the second direction D2 is the lateral direction of the substrate 6D.

[0104] The substrate 6D is provided with through holes 63D, 64D, and 65D that penetrate through the thickness direction. The centers of the through holes 63D and 64D are located at different positions when viewed from the first direction D1 and the second direction D2. Similarly, the centers of the through holes 64D and 65D are located at different positions when viewed from the first direction D1 and the second direction D2. Furthermore, the centers of the through holes 63D and 64D are located at the same position when viewed from the first direction D1 but at different positions when viewed from the second direction D2.

[0105] The first air core coil 21D is formed around a through hole 63D of the substrate 6D. The second air core coil 22D is formed around a through hole 64D of the substrate 6D, and the third air core coil 23D is formed around a through hole 65D of the substrate 6D. Each of the first air core coil 21D, second air core coil 22D, and third air core coil 23D is a substrate-mounted Rogowski coil, i.e., formed by providing wiring wound in the thickness direction of the substrate 6D on the substrate 6D (omitted in FIG. 10 ). Each of the first air core coil 21D, second air core coil 22D, and third air core coil 23D has a circular ring shape when viewed in the thickness direction of the substrate 6D.

[0106] The through hole 63D has a shape that allows the first electrical circuit LA1 to pass therethrough. Similarly, the through hole 64D has a shape that allows the second electrical circuit LA2 to pass therethrough, and the through hole 65D has a shape that allows the third electrical circuit LA3 to pass therethrough. The circuit board 6D is attached to the branch breaker A3 corresponding to the electric leakage determination device 1D so that the first electrical circuit LA1 passes through the through hole 63D, the second electrical circuit LA2 passes through the through hole 64D, and the third electrical circuit LA3 passes through the through hole 65D. That is, the first air core coil 21D generates an output corresponding to the first current IA1 passing through the through hole 63D. Similarly, the second air core coil 22D generates an output corresponding to the second current IA2 passing through the through hole 64D, and the third air core coil 23D generates an output corresponding to the third current IA3 passing through the through hole 65D.

[0107] The center of the first air core coil 21D and the center of the second air core coil 22D are located at different positions when viewed from each of the first direction D1 and the second direction D2. Similarly, the center of the second air core coil 22D and the center of the third air core coil 23D are located at different positions when viewed from each of the first direction D1 and the second direction D2. Furthermore, the center of the first air core coil 21D and the center of the third air core coil 23D are located at the same position when viewed from the first direction D1 but at different positions when viewed from the second direction D2. Here, the "center of the third air core coil 23D" refers to the center of the region occupied by the third air core coil 23D when viewed from the thickness direction of the substrate 6D, and more specifically, the center of the annular-shaped third air core coil 23D when viewed from the thickness direction of the substrate 6D. This configuration allows the number of turns of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D to be increased, thereby improving the measurement accuracy of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D, which has the advantage of improving the accuracy with which the leakage current detection device 1D determines a leakage current.

[0108] In the second embodiment, the substrate 6D in each of the multiple electric leakage determination devices 1D is a single substrate. That is, in the second embodiment, the multiple electric leakage determination devices 1D share the substrate 6D, and the single substrate 6D is attached to the multiple branch breakers A3 corresponding to each of the multiple electric leakage determination devices 1D. The substrate 6D in the second embodiment has multiple through holes 63D, multiple through holes 64D, and multiple through holes 65D. The multiple through holes 63D are arranged in a line in the first direction D1. Similarly, the multiple through holes 64D are arranged in a line in the first direction D1, and the multiple through holes 65D are arranged in a line in the first direction D1. Furthermore, the centers of the multiple through holes 63D and the multiple through holes 64D are arranged at different positions when viewed from the first direction D1 and the second direction D2. Similarly, the center of each of the plurality of through holes 64D and the center of each of the plurality of through holes 65D are located at different positions when viewed from each of the first direction D1 and the second direction D2. The substrate 6D of the second embodiment is mounted so that the first electrical path LA1 passes through one of the plurality of through holes 63D, the second electrical path LA2 passes through one of the plurality of through holes 64D, and the second electrical path LA2 passes through one of the plurality of through holes 64D.

[0109] The first air core coil 21D in each of the plurality of electric leakage determination devices 1D corresponds one-to-one to the plurality of through holes 63D and is formed around the corresponding through hole 63D. Similarly, the second air core coil 22D in each of the plurality of electric leakage determination devices 1D corresponds one-to-one to the plurality of through holes 64D and is formed around the corresponding through hole 64D. Furthermore, the third air core coil 23D in each of the plurality of electric leakage determination devices 1D corresponds one-to-one to the plurality of through holes 65D and is formed around the corresponding through hole 65D.

[0110] The conversion unit 3D converts the input analog signal into a digital signal. In the second embodiment, one conversion unit 3D is provided for each set of a first air core coil 21D, a second air core coil 22D, and a third air core coil 23D. The conversion unit 3D is configured as a single integrated circuit (e.g., an application-specific integrated circuit (ASIC)). The conversion unit 3D is provided on a substrate 6D. In the second embodiment, the first terminal of the conversion unit 3D is electrically connected to the positive electrode of the first air core coil 21D, and the second terminal of the conversion unit 3D is electrically connected to the negative electrode of the first air core coil 21D. Similarly, the third terminal of the conversion unit 3D is electrically connected to the positive electrode of the second air core coil 22D, and the fourth terminal of the conversion unit 3D is electrically connected to the negative electrode of the second air core coil 22D. Furthermore, the fifth terminal of conversion unit 3D is electrically connected to the positive electrode of third air core coil 23D, and the sixth terminal of conversion unit 3D is electrically connected to the negative electrode of third air core coil 23D. Furthermore, conversion unit 3D sequentially acquires, in a time-division manner, a first measurement signal Si1 input from first air core coil 21D, a second measurement signal Si2 input from second air core coil 22D, and a third measurement signal Si3 input from third air core coil 23D.

[0111] The converter 3D digitally converts each of the first measurement signal Si1 input from the first air core coil 21D, the second measurement signal Si2 input from the second air core coil 22D, and the third measurement signal Si3 input from the third air core coil 23D. That is, the first measurement signal Si1 input from the first air core coil 21D, the second measurement signal Si2 input from the second air core coil 22D, and the third measurement signal Si3 input from the third air core coil 23D are all digitally converted by the same converter 3D. This configuration allows the electric leakage determination device 1D to prevent differences from occurring among the digitally converted output of the first air core coil 21D, the digitally converted output of the second air core coil 22D, and the digitally converted output of the third air core coil 23D. Therefore, the electric leakage determination device 1D of embodiment 2 has the advantage of being able to accurately determine an electric leakage.

[0112] More specifically, the converter 3D amplifies each of the first, second, and third measurement signals Si1, Si2, and Si3, converts the amplified first, second, and third measurement signals Si1, Si2, and Si3 into digital signals, and outputs the digitally converted first, second, and third measurement signals Si1, Si2, and Si3 to the calculator 4D.

[0113] The calculator 4D calculates the sum of the first current IA1, the second current IA2, and the third current IA3 based on the first measurement signal Si1, the second measurement signal Si2, and the third measurement signal Si3 that have been digitally converted by the converter 3D. That is, the calculator 4D calculates the sum of the first current IA1, the second current IA2, and the third current IA3 based on the digitally converted first measurement signal Si1, the second measurement signal Si2, and the third measurement signal Si3 that have been input from the converter 3D. More specifically, the calculator 4D calculates the current values ​​of the first current IA1, the second current IA2, and the third current IA3 based on the first measurement signal Si1, the second measurement signal Si2, and the third measurement signal Si3 that have been input from the converter 3D, and calculates the sum of the current values ​​of the first current IA1, the second current IA2, and the third current IA3.

[0114] Specifically, the calculation unit 4D integrates the first measurement signal Si1, the second measurement signal Si2, and the third measurement signal Si3 input from the conversion unit 3D. The first measurement signal Si1 output from the first air core coil 21D indicates the differentiated value of the first current IA1. The second measurement signal Si2 output from the second air core coil 22D indicates the differentiated value of the second current IA2. The third measurement signal Si3 output from the third air core coil 23D indicates the differentiated value of the third current IA3. Therefore, the calculation unit 4D integrates the first measurement signal Si1 digitally converted by the conversion unit 3D to generate a digital signal indicating the current value of the first current IA1. Similarly, the calculation unit 4D integrates the second measurement signal Si2 digitally converted by the conversion unit 3D to generate a digital signal indicating the current value of the second current IA2. Furthermore, the calculation unit 4D integrates the third measurement signal Si3 converted by the conversion unit 3D to generate a digital signal indicating the current value of the third current IA3. The calculation unit 4D calculates the sum of the instantaneous current values ​​of the first current IA1, the second current IA2, and the third current IA3 based on the digital signals indicating the current values ​​of the first current IA1, the second current IA2, and the third current IA3, and generates data indicating the calculated sum. The calculation unit 4D outputs the data indicating the calculated sum as a power signal to the determination unit 5D.

[0115] The determination unit 5D determines whether a ground fault has occurred in the circuit CA1 based on the sum of the first current IA1, the second current IA2, and the third current IA3 calculated by the calculation unit 4D. More specifically, the determination unit 5D compares the sum of the instantaneous values ​​of the first current IA1, the second current IA2, and the third current IA3 with a predetermined tolerance range. The determination unit 5D determines that a ground fault has occurred in the circuit CA1 if the sum is outside the tolerance range, and determines that a ground fault has not occurred in the circuit CA1 if the sum is within the tolerance range. The determination unit 5D of the second embodiment outputs the determination result to the transmission unit 7 and a tripping control unit 93D (see FIG. 9 ) of the circuit breaker 10D, which will be described later.

[0116] The leakage current determination device 1D preferably includes a computer system. In the computer system, a processor such as a CPU or MPU reads and executes a program stored in memory, thereby realizing the functions of the calculation unit 4D and the determination unit 5D. The computer system includes a processor that operates according to the program as its main hardware component. The type of processor is not important as long as it can realize the functions by executing the program. The processor is composed of one or more electronic circuits, including an IC or LSI. While the terms IC and LSI are used here, the term may be changed depending on the degree of integration, and may be called a system LSI, VLSI, or ULSI. Field programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, or reconfigurable logic devices that can reconfigure the connections within the LSI or set up circuit partitions within the LSI, can also be used for the same purpose. Multiple electronic circuits may be integrated on a single chip or provided on multiple chips. Multiple chips may be integrated into a single device or provided on multiple devices.

[0117] (2-2-2) Circuit Breaker Hereinafter, a detailed configuration of the circuit breaker 10D of the second embodiment will be described with reference to FIG.

[0118] As shown in FIG. 9, the circuit breaker 10D includes the above-described earth leakage determining device 1D, a breaker unit 91D, an operating unit 92D, and a breaker control unit 93D.

[0119] When the operation unit 92D is operated, the breaker 91D breaks the circuit CA1. More specifically, when the operation unit 92D is operated, the breaker 91D forcibly opens a contact 911D inserted in the first electrical circuit LA1, a contact 912D inserted in the second electrical circuit LA2, and a contact 913D inserted in the third electrical circuit LA3, thereby breaking the circuit CA1.

[0120] Furthermore, the cutoff unit 91D cuts off the circuit CA1 based on the control content of the cutoff control unit 93D. The cutoff control unit 93D controls whether the cutoff unit 91D cuts off the circuit CA1 based on the determination result input from the determination unit 5D of the electric leakage determination device 1D. The cutoff control unit 93D controls the cutoff unit 91D to cut off the circuit CA1 when the determination unit 5D determines that an electric leakage has occurred in the circuit CA1. In other words, the cutoff unit 91D cuts off the circuit CA1 when the determination unit 5D determines that an electric leakage has occurred in the circuit CA1.

[0121] (2-2-3) Distribution Board The detailed configuration of the distribution board A1 of the second embodiment will be described below.

[0122] The distribution board A1 of the second embodiment includes a main breaker A2, a plurality of branch breakers A3, an electric leakage determination device 1D, and a cabinet A4. Hereinafter, a description of the configuration of the distribution board A1 of the second embodiment that is similar to that of the distribution board A1 of the second embodiment will be omitted. In the following description, it is assumed that the electric leakage determination device 1D determines whether an electric leakage has occurred in the first electric circuit LA1, the second electric circuit LA2, and the third electric circuit LA3 connected to the main breaker A2. In the distribution board A1 of the second embodiment, it is assumed that a three-phase, three-wire service line of a system power supply (commercial power supply) is electrically connected to the primary terminal of the main breaker A2.

[0123] The main breaker A2 of the second embodiment includes a primary terminal and a secondary terminal. The primary terminal of the main breaker A2 is electrically connected to a three-phase, three-wire service line of a system power supply (commercial power supply). The secondary terminal of the main breaker A2 is electrically connected to each of a plurality of branch breakers A3 via three conductive bars.

[0124] The leakage current determination device 1D of the second embodiment determines whether a leakage current has occurred in a circuit CA1 included in a main breaker A2. More specifically, the leakage current determination device 1D determines whether a leakage current has occurred in a circuit CA1 that electrically connects the main breaker A2 to loads (electrical circuits) connected to each of a plurality of branch breakers A3 via each of the plurality of branch breakers A3. That is, the circuit CA1 includes any two of the three conductive bars that electrically connect the corresponding branch breaker A3 to the main breaker A2 and an electrical circuit connected to a secondary terminal of each of the plurality of branch breakers A3.

[0125] The electric leakage determination device 1D of the second embodiment is provided on the distribution board A1 so that the first air core coil 21D measures the current flowing in the R-phase voltage line of the electric service line, the second air core coil 22D measures the current flowing in the S-phase voltage line of the electric service line, and the third air core coil 23D measures the current flowing in the T-phase voltage line of the electric service line. More specifically, the circuit board 6D of the electric leakage determination device 1D is attached to the main breaker A2 so that the R-phase voltage line of the electric service line passes through the through hole 63D, the S-phase voltage line of the electric service line passes through the through hole 64D, and the T-phase voltage line of the electric service line passes through the through hole 65D. The determination unit 5D of the electric leakage determination device 1D determines whether an electric leakage has occurred in the circuit CA1 based on the sum of the currents flowing in the R-phase, S-phase, and T-phase voltage lines of the electric service line. In short, in the above-described leakage determination device 1D, the first electric circuit LA1 is an R-phase voltage line of a three-phase three-wire system, the second electric circuit LA2 is an S-phase voltage line of the three-phase three-wire system, and the third electric circuit LA3 is a T-phase voltage line of the three-phase three-wire system. This configuration has the advantage that when determining whether or not there is a leakage in the current flowing through each of the voltage lines in the R, S, and T phases of the three-phase three-wire system, the sensor characteristics of each of the multiple coils can be easily matched.

[0126] (2-3) Modifications of Embodiment 2 The above-described embodiment 2 is merely one of various embodiments of the present disclosure. The above-described embodiment 2 can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. The following modifications may be realized in appropriate combination. The same components as those in the above-described embodiment 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0127] (2-3-1) First Modification of Embodiment 2 In the electric leakage determination device 1D of the above-described embodiment 2, the center of the first air core coil 21D and the center of the second air core coil 22D are located at different positions when viewed from each of the first direction D1 and the second direction D2, and the center of the second air core coil 22D and the center of the third air core coil 23D are located at different positions when viewed from each of the first direction D1 and the second direction D2. However, in the electric leakage determination device 1E of the first modification shown in Fig. 11, the center of the first air core coil 21E, the center of the second air core coil 22E, and the center of the third air core coil 23E are located so as to be aligned in the first direction D1.

[0128] The detailed configuration of the electric leakage determination device 1E of the first modified example will be described below.

[0129] The leakage current determination device 1E of the first modified example includes a first air core coil 21E, a second air core coil 22E, a conversion unit 3, a calculation unit 4, a determination unit 5, a substrate 6E, and a transmission unit 7.

[0130] The substrate 6E is provided with through holes 63E, 64E, and 65E that penetrate through the thickness direction. The centers of the through holes 63E, 64E, and 65E are located at the same position when viewed from the first direction D1, but at different positions when viewed from the second direction D2. In other words, the centers of the through holes 63E, 64E, and 65E are aligned in the first direction D1.

[0131] The first air core coil 21E is formed around a through hole 63E in the substrate 6E. The second air core coil 22E is formed around a through hole 64E in the substrate 6E, and the third air core coil 23E is formed around a through hole 65E in the substrate 6E. Therefore, the centers of the first air core coil 21E, the second air core coil 22E, and the third air core coil 23E are formed at the same position when viewed from the first direction D1, but at different positions when viewed from the second direction D2. In other words, the centers of the first air core coil 21E, the second air core coil 22E, and the third air core coil 23E are formed to be aligned in the first direction D1.

[0132] In the electric leakage determination device 1E of the first modification, similar to the electric leakage determination device 1E of the second embodiment, the substrate 6A in each of the plurality of electric leakage determination devices 1A is a single substrate. That is, in the first modification, each of the plurality of electric leakage determination devices 1E shares the substrate 6E, and the substrate 6E is provided with a plurality of through holes 63E, a plurality of through holes 64E, and a plurality of through holes 65E. The plurality of through holes 63E are arranged side by side in the first direction D1. Similarly, the plurality of through holes 64E are arranged side by side in the first direction D1, and the plurality of through holes 65E are arranged side by side in the first direction D1. Furthermore, the centers of the plurality of through holes 63E, the centers of the plurality of through holes 64E, and the centers of the plurality of through holes 65E are located at the same position when viewed from the first direction D1. The substrate 6E of the first modified example is attached so that the first electric circuit LA1, the second electric circuit LA2, and the third electric circuit LA3 connected to each of the plurality of branch breakers A3 pass through the corresponding through holes 63E, 64E, and 65E.

[0133] (2-3-2) Other Modifications of Embodiment 2 Other modifications of the above-described embodiment 2 are listed below. The following modifications may be realized in appropriate combination. Furthermore, functions similar to those of the electric leakage determination device 1D according to the above-described embodiment 2 may be embodied as a computer program, a non-transitory recording medium on which a program is recorded, or the like. The program according to one aspect is a program that causes one or more processors of a computer system to realize the functions of the electric leakage determination device 1D according to the above-described embodiment 2.

[0134] The leakage detection device 1D may include a plurality of substrates 6D, which may be stacked along the thickness direction (vertical direction) of each of the substrates 6D. In this case, the first air core coils 21D on each of the substrates 6 are aligned along the thickness direction, the second air core coils 22D on each of the substrates 6 are aligned along the thickness direction, and the third air core coils 23D on each of the substrates 6 are aligned along the thickness direction. More specifically, in the above configuration, the first terminal of the conversion unit 3D is electrically connected to the positive electrode of the topmost first air core coil 21D of the plurality of first air core coils 21D aligned along the thickness direction, and the second terminal of the conversion unit 3D is electrically connected to the positive electrode of the bottommost first air core coil 21D of the plurality of first air core coils 21D aligned along the thickness direction. Furthermore, the negative electrode of each of the plurality of first air core coils 21D, excluding both the topmost first air core coil 21D and the bottommost first air core coil 21D, is electrically connected to the positive electrode of the first air core coil 21D located below it. Similarly, the third terminal of the conversion unit 3D is electrically connected to the positive electrode of the topmost second air core coil 22D of the plurality of second air core coils 22D located along the thickness direction, and the fourth terminal of the conversion unit 3D is electrically connected to the positive electrode of the bottommost second air core coil 22D of the plurality of second air core coils 22D located along the thickness direction. The negative electrode of each of the plurality of second air core coils 22D, excluding both the topmost second air core coil 22D and the bottommost second air core coil 22D, is electrically connected to the positive electrode of the bottommost second air core coil 22D located below it. Furthermore, the fifth terminal of the conversion unit 3D is electrically connected to the positive electrode of the third air core coil 23D that is arranged at the top of the plurality of third air core coils 23D lined up along the thickness direction, and the sixth terminal of the conversion unit 3D is electrically connected to the positive electrode of the third air core coil 23D that is arranged at the bottom of the plurality of third air core coils 23D lined up along the thickness direction. The negative electrode of each of the plurality of third air core coils 23D, excluding both the topmost and bottommost third air core coils 23D, is electrically connected to the positive electrode of the third air core coil 23D lined up below it.The conversion unit 3 sequentially acquires the first measurement signal Si1 input from the plurality of first air-core coils 21, the second measurement signal Si2 input from the plurality of second air-core coils 22, and the third measurement signal Si3 input from the plurality of third air-core coils 23 in a time-division manner.

[0135] With the above configuration, the outputs of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D can be increased, thereby increasing the sensitivity of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D. In other words, the measurement accuracy of the first air core coil 21D, the second air core coil 22D, and the third air core coil 23D can be improved. As a result, there is an advantage in that the accuracy with which the electric leakage detection device 1D determines an electric leakage can be improved.

[0136] In the second embodiment described above, the leakage determination device 1D determines whether a leakage current has occurred in the circuit CA1 of the main breaker A2. However, the leakage determination device 1D may also determine whether a leakage current has occurred in the circuit CA1 of one of the branch breakers A3. That is, the leakage determination device 1D may determine whether a leakage current has occurred in the circuit CA1 of at least one of the main breaker A2 and the branch breakers A3.

[0137] In the second embodiment, the circuit board 6D in each of the plurality of electric leakage determination devices 1D is a single circuit board, but the circuit boards may be separate. That is, the plurality of electric leakage determination devices 1D do not need to share the circuit board 6D.

[0138] (Summary) A first aspect of the earth leakage determination device (1, 1A to 1C) is a ground leakage determination device that determines whether an earth leakage has occurred in a single-phase circuit (C1) having at least a first electric circuit (L1) and a second electric circuit (L2). The first aspect of the earth leakage determination device (1, 1A to 1C) includes a first air core coil (21, 21A, 21B), a second air core coil (22, 22A, 22B), a calculation unit (4), and a determination unit (5). The first air core coil (21, 21A, 21B) measures a first current (I1) that is a current flowing in the first electric circuit (L1). The second air core coil (22, 22A, 22B) measures a second current (I2) that is a current flowing in the second electric circuit (L2). A calculation unit (4) calculates the difference between the first current (I1) and the second current (I2). A determination unit (5) determines whether or not a leakage current has occurred based on the difference.

[0139] This embodiment has the advantage that it is possible to easily match the sensor characteristics of each of the multiple coils that measure current to determine a ground fault.

[0140] The leakage current determination device (1, 1A to 1C) of the second aspect is the same as that of the first aspect, and further includes a conversion unit (3, 3A, 3B) that converts an input analog signal into digital. The first air-core coil (21, 21A, 21B) outputs a first measurement signal (Si1), which is an analog signal including a measurement result of a first current (I1), to the conversion unit (3, 3A, 3B). The second air-core coil (22, 22A, 22B) outputs a second measurement signal (Si2), which is an analog signal including a measurement result of a second current (I2), to the conversion unit (3, 3A, 3B). The conversion unit (3, 3A, 3B) digitally converts each of the first measurement signal (Si1) and the second measurement signal (Si2). The calculation unit (4) calculates a difference based on the first measurement signal (Si1) and the second measurement signal (Si2) that have been digitally converted by the conversion unit (3, 3A, 3B).

[0141] This embodiment has the advantage that it is possible to accurately determine whether a ground fault has occurred.

[0142] The third aspect of the leakage current detection device (1, 1A to 1C) is the first or second aspect, and further includes a substrate (6, 6A, 6B) on which a first air core coil (21, 21A, 21B) and a second air core coil (22, 22A, 22B) are provided.

[0143] According to this aspect, there is an advantage that the first air core coil (21, 21A, 21B) and the second air core coil (22, 22A, 22B) can be manufactured efficiently.

[0144] The leakage current determining device (1, 1A-1C) of the fourth aspect is the third aspect, but includes a plurality of substrates (6, 6A, 6B). The plurality of substrates (6, 6A, 6B) are stacked and arranged along the thickness direction of each of the plurality of substrates (6, 6A, 6B). The first air core coils (21, 21A, 21B) on each of the plurality of substrates (6, 6A, 6B) are aligned along the thickness direction. The second air core coils (22, 22A, 22B) on each of the plurality of substrates (6, 6A, 6B) are aligned along the thickness direction.

[0145] According to this aspect, there is an advantage that the accuracy with which the leakage determination device (1, 1A to 1C) determines leakage can be improved.

[0146] In the fifth aspect of the leakage current determination device (1, 1A to 1C), in the third or fourth aspect, the substrate (6, 6A, 6B) has a first side (61) along a first direction (D1) and a second side (62) along a second direction (D2) that intersects with the first direction (D1). The center of the first air core coil (21, 21A, 21B) and the center of the second air core coil (22, 22A, 22B) are located at different positions from each other when viewed from each of the first direction (D1) and the second direction (D2).

[0147] According to this aspect, there is an advantage that the accuracy with which the leakage determination device (1, 1A to 1C) determines leakage can be improved.

[0148] In the sixth aspect of the leakage current detection device (1, 1A to 1C), in any one of the first to fifth aspects, the positive electrode of the first air core coil (21, 21A, 21B) and the positive electrode of the second air core coil (22, 22A, 22B) are electrically connected. The negative electrode of the first air core coil (21, 21A, 21B) and the negative electrode of the second air core coil (22, 22A, 22B) are electrically connected.

[0149] This aspect has the advantage of reducing the load on the conversion unit (3, 3A, 3B).

[0150] In the seventh aspect of the earth leakage determination device (1, 1A to 1C) of any one of the first to sixth aspects, the circuit (C1) is a single-phase two-wire system. The first electric circuit (L1) is a voltage line of the single-phase two-wire system. The second electric circuit (L2) is a neutral line of the single-phase two-wire system.

[0151] According to this aspect, when determining whether or not there is a leakage current flowing between the neutral line and the voltage line of a single-phase three-wire system, there is an advantage in that the sensor characteristics of each of the multiple coils can be easily matched.

[0152] In the eighth aspect of the earth leakage determination device (1, 1A to 1C) of any one of the first to seventh aspects, the circuit (C1) is a single-phase three-wire system. The first electric circuit (L1) is a neutral wire of the single-phase three-wire system. The second electric circuit (L2) is one of two voltage wires of the single-phase three-wire system.

[0153] According to this aspect, when determining whether or not there is a leakage current flowing between the neutral line and the voltage line of a single-phase three-wire system, there is an advantage in that the sensor characteristics of each of the multiple coils can be easily matched.

[0154] In a ninth aspect of the earth leakage determination device (1, 1A-1C), in any one of the first to eighth aspects, the circuit (C1) is a single-phase three-wire system. The first electric circuit (L1) is one of two voltage lines of the single-phase three-wire system. The second electric circuit (L2) is the other of the two voltage lines.

[0155] According to this aspect, when determining whether or not there is a leakage current flowing between two voltage lines in a single-phase three-wire system, there is an advantage in that the sensor characteristics of each of the multiple coils can be easily matched.

[0156] A tenth aspect of the leakage current determination device (1D, 1E) is a leakage current determination device that determines whether or not a leakage current has occurred in a three-phase circuit (CA1) having a first electric circuit (LA1), a second electric circuit (LA2), and a third electric circuit (LA3). The tenth aspect of the leakage current determination device (1D, 1E) includes a first air core coil (21D, 21E), a second air core coil (22D, 22E), a third air core coil (23D, 23E), a calculation unit (4D), and a determination unit (5D). The first air core coil (21D, 21E) measures a first current (IA1) that is a current flowing in the first electric circuit (LA1). The second air core coil (22D, 22E) measures a second current (IA2) that is a current flowing in the second electric circuit (LA2). The third air-core coil (23D, 23E) measures a third current (IA3) that is a current flowing through the third current path (LA3). A calculation unit (4D) calculates a sum of the first current (IA1), the second current (IA2), and the third current (IA3). A determination unit (5D) determines whether or not a leakage current has occurred based on the sum.

[0157] This embodiment has the advantage that it is possible to easily match the sensor characteristics of each of the multiple coils that measure current to determine a ground fault.

[0158] The leakage current determination device (1D, 1E) of an eleventh aspect is the same as that of the tenth aspect, and further includes a converter (3D) that converts an input analog signal into digital. The first air-core coil (21D, 21E) outputs a first measurement signal (Si1), which is an analog signal including a measurement result of the first current (IA1), to the converter (3D). The second air-core coil (22D, 22E) outputs a second measurement signal (Si2), which is an analog signal including a measurement result of the second current (IA2), to the converter (3D). The third air-core coil (23D, 23E) outputs a third measurement signal (Si3), which is an analog signal including a measurement result of the third current (IA3), to the converter (3D). The converter (3D) digitally converts each of the first measurement signal (Si1), the second measurement signal (Si2), and the third measurement signal (Si3). The calculation section (4D) calculates a sum value based on the first measurement signal (Si1), the second measurement signal (Si2), and the third measurement signal (Si3) that have been digitally converted by the conversion section (3D).

[0159] This embodiment has the advantage that it is possible to accurately determine whether a ground fault has occurred.

[0160] The leakage current detection device (1D, 1E) of the 12th aspect is the 10th or 11th aspect, and further includes a substrate (6D, 6E) on which a first air core coil (21D, 21E), a second air core coil (22D, 22E), and a third air core coil (23D, 23E) are provided.

[0161] According to this aspect, there is an advantage that the first air core coil (21D, 21E), the second air core coil (22D, 22E), and the third air core coil (23D, 23E) can be manufactured efficiently.

[0162] The leakage current determining device (1D, 1E) of the thirteenth aspect is the same as that of the twelfth aspect, but includes a plurality of substrates (6D, 6E). The plurality of substrates (6D, 6E) are arranged in a stacked manner along the thickness direction of each of the plurality of substrates (6D, 6E). The first air core coils (21D, 21E) on each of the plurality of substrates (6D, 6E) are aligned along the thickness direction. The second air core coils (22D, 22E) on each of the plurality of substrates (6D, 6E) are aligned along the thickness direction. The third air core coils (23D, 23E) on each of the plurality of substrates (6D, 6E) are aligned along the thickness direction.

[0163] This embodiment has the advantage of improving the accuracy of determining a ground fault.

[0164] In the leakage current detection device (1D, 1E) of the 14th aspect, in the 12th or 13th aspect, the substrate (6D, 6E) has a first side (61) along a first direction (D1) and a second side (62) along a second direction (D2) intersecting the first direction (D1). The center of the first air core coil (21D, 21E) and the center of the second air core coil (22D, 22E) are located at different positions from each other when viewed from each of the first direction (D1) and the second direction (D2). The center of the second air core coil (22D, 22E) and the center of the third air core coil (23D, 23E) are located at different positions from each other when viewed from each of the first direction (D1) and the second direction (D2).

[0165] This embodiment has the advantage of improving the accuracy of determining a ground fault.

[0166] In a fifteenth aspect of the earth leakage determination device (1D, 1E), in any one of the tenth to fourteenth aspects, the circuit (CA1) is a three-phase three-wire system. The first electric circuit (LA1) is an R-phase voltage line of the three-phase three-wire system. The second electric circuit (LA2) is an S-phase voltage line of the three-phase three-wire system. The third electric circuit (LA3) is a T-phase voltage line of the three-phase three-wire system.

[0167] According to this aspect, when determining whether or not there is a leakage current in the voltage lines in each of the R phase, S phase, and T phase of a three-phase, three-wire system, there is an advantage in that the sensor characteristics of each of the multiple coils can be easily matched.

[0168] A circuit breaker (10, 10D) of a 16th aspect includes the leakage current determination device (1, 1A to 1E) of any one of the first to 15th aspects and a breaker unit (91, 91D). The breaker unit (91, 91D) breaks the circuit (CA1) when the determination unit (5, 5D) determines that a leakage current has occurred.

[0169] This aspect has the advantage of being able to provide a circuit breaker in which the sensor characteristics of each of a plurality of coils that measure current to determine a ground fault can be easily matched.

[0170] A distribution board (A1) of a seventeenth aspect includes a main breaker (A2), a plurality of branch breakers (A3), and an earth leakage determination device (1, 1A-1E) of any one of the first to fifteenth aspects. The plurality of branch breakers (A3) are electrically connected to secondary terminals of the main breaker (A2). The earth leakage determination device (1, 1A-1E) determines whether an earth leakage has occurred in a circuit (CA1) included in at least one of the main breaker (A2) and the plurality of branch breakers (A3).

[0171] According to this aspect, there is an advantage in that it is possible to provide a distribution board in which the sensor characteristics of each of a plurality of coils that measure current to determine a ground fault can be easily matched.

[0172] The program of the eighteenth aspect causes one or more processors of a computer system to realize the functions of the earth leakage determination device (1, 1A to 1E) of any one of the first to fifteenth aspects.

[0173] This embodiment has the advantage that it is possible to easily match the sensor characteristics of each of the multiple coils that measure current to determine a ground fault.

[0174] 1, 1A to 1E Leakage current determination device 3, 3A, 3B, 3D Conversion unit 4, 4D Calculation unit 5, 5D Determination unit 6, 6A, 6B, 6D, 6E Circuit board 61 First side 62 Second side 10 Circuit breaker 10D Circuit breaker 21, 21A, 21B, 21D, 21E First air core coil 22, 22A, 22B, 22D, 22E Second air core coil 23D, 23E Third air core coil 91, 91D Breaker unit A1 Distribution board A2 Main breaker A3 Branch breaker C1, CA1 Circuit D1 First direction D2 Second direction I1, IA1 First current I2, IA2 Second current IA3 Third current L1, LA1 First electric circuit L2, LA2 Second electric circuit LA3 Third electric circuit Si1 First measurement signal Si2 Second measurement signal Si3 Third measurement signal

Claims

1. A leakage current determination device that determines whether or not a leakage current has occurred in a single-phase circuit having at least a first electric circuit and a second electric circuit, comprising: a first air-core coil that measures a first current that is a current flowing in the first electric circuit; a second air-core coil that measures a second current that is a current flowing in the second electric circuit; a calculation unit that calculates the difference between the first current and the second current; and a determination unit that determines whether or not the leakage current has occurred based on the difference.

2. The leakage current determination device according to claim 1, further comprising a conversion unit that converts an input analog signal into digital, wherein the first air-core coil outputs a first measurement signal to the conversion unit, the first measurement signal being an analog signal including a measurement result of the first current, and the second air-core coil outputs a second measurement signal to the conversion unit, the second measurement signal being an analog signal including a measurement result of the second current, the conversion unit digitally converts each of the first measurement signal and the second measurement signal, and the calculation unit calculates the difference based on the first measurement signal and the second measurement signal digitally converted by the conversion unit.

3. The leakage current determining device according to claim 1 or 2, further comprising a substrate on which the first air core coil and the second air core coil are mounted.

4. A leakage current determination device as described in claim 3, comprising a plurality of the substrates, the plurality of substrates being stacked along the thickness direction of each of the plurality of substrates, the first air core coils on each of the plurality of substrates being aligned along the thickness direction, and the second air core coils on each of the plurality of substrates being aligned along the thickness direction.

5. The leakage current determination device according to claim 3 or 4, wherein the substrate has a first side along a first direction and a second side along a second direction intersecting the first direction, and the center of the first air core coil and the center of the second air core coil are located at different positions when viewed from each of the first direction and the second direction.

6. A leakage current detection device as described in any one of claims 1 to 5, wherein the positive electrode of the first air core coil and the positive electrode of the second air core coil are electrically connected, and the negative electrode of the first air core coil and the negative electrode of the second air core coil are electrically connected.

7. The leakage current determination device according to any one of claims 1 to 6, wherein the circuit is a single-phase two-wire system, the first electric circuit is a voltage line of the single-phase two-wire system, and the second electric circuit is a neutral line of the single-phase two-wire system.

8. The leakage current determination device according to any one of claims 1 to 7, wherein the circuit is a single-phase three-wire system, the first electric circuit is a neutral wire of the single-phase three-wire system, and the second electric circuit is one of two voltage wires of the single-phase three-wire system.

9. The leakage current determination device according to any one of claims 1 to 8, wherein the circuit is a single-phase three-wire system, the first electric circuit is one of two voltage lines of the single-phase three-wire system, and the second electric circuit is the remaining voltage line of the two voltage lines.

10. A leakage current determination device for determining whether or not a leakage current has occurred in a three-phase circuit having a first electric circuit, a second electric circuit, and a third electric circuit, comprising: a first air core coil for measuring a first current that is a current flowing in the first electric circuit; a second air core coil for measuring a second current that is a current flowing in the second electric circuit; a third air core coil for measuring a third current that is a current flowing in the third electric circuit; a calculation unit for calculating the sum of the first current, the second current, and the third current; and a determination unit for determining whether or not the leakage current has occurred based on the sum.

11. The leakage current determination device according to claim 10, further comprising a conversion unit that converts an input analog signal into digital, wherein the first air core coil outputs a first measurement signal to the conversion unit, the first measurement signal being an analog signal including a measurement result of the first current, the second air core coil outputs a second measurement signal to the conversion unit, the second measurement signal being an analog signal including a measurement result of the second current, the third air core coil outputs a third measurement signal to the conversion unit, the third measurement signal being an analog signal including a measurement result of the third current, the conversion unit digitally converts each of the first measurement signal, the second measurement signal, and the third measurement signal, and the calculation unit calculates the sum based on the first measurement signal, the second measurement signal, and the third measurement signal that have been digitally converted by the conversion unit.

12. The leakage current determining device according to claim 10 or 11, further comprising a substrate on which the first air core coil, the second air core coil, and the third air core coil are mounted.

13. A leakage current determination device as described in claim 12, comprising a plurality of substrates, the plurality of substrates being stacked and arranged along the thickness direction of each of the plurality of substrates, the first air core coils on each of the plurality of substrates being aligned along the thickness direction, the second air core coils on each of the plurality of substrates being aligned along the thickness direction, and the third air core coils on each of the plurality of substrates being aligned along the thickness direction.

14. The leakage current determination device described in claim 12 or 13, wherein the substrate has a first side along a first direction and a second side along a second direction intersecting the first direction, the center of the first air core coil and the center of the second air core coil are positioned at different positions when viewed from each of the first direction and the second direction, and the center of the second air core coil and the center of the third air core coil are positioned at different positions when viewed from each of the first direction and the second direction.

15. The leakage current determination device according to any one of claims 10 to 14, wherein the circuit is a three-phase three-wire system, the first electric circuit is an R-phase voltage line of the three-phase three-wire system, the second electric circuit is an S-phase voltage line of the three-phase three-wire system, and the third electric circuit is a T-phase voltage line of the three-phase three-wire system.

16. A circuit breaker comprising: an electric leakage determination device according to any one of claims 1 to 15; and a breaker that breaks the circuit when the determination unit determines that the electric leakage has occurred.

17. A distribution board comprising: a main breaker; a plurality of branch breakers electrically connected to the secondary terminal of the main breaker; and a leakage current determination device according to any one of claims 1 to 15, which determines whether or not a leakage current has occurred in the circuit of at least one of the main breaker and the plurality of branch breakers.

18. A program that causes one or more processors of a computer system to realize the functions of the earth leakage determination device according to any one of claims 1 to 15.

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