Leakage current detection system, distribution board, leakage current detection method, and program

Abstract

To reduce the number of zero-phase current transformers while making it easier to identify leakage points at the branch circuit level. [Solution] The leakage current identification system 1 comprises a first acquisition unit 11, a second acquisition unit 12, and an identification unit 14. The first acquisition unit 11 acquires leakage current detection information based on the detection result of zero-sequence current detected by a zero-sequence current transformer installed in the main circuit. The second acquisition unit 12 acquires load current information based on the detection result of load current detected by one or more branch current detection units installed in each of a plurality of branch circuits, including at least one identification circuit. The identification unit 14 identifies the branch circuit in which a leakage current has occurred among the plurality of branch circuits based on the leakage current detection information and the plurality of load current information related to the plurality of branch circuits. The identification circuit is a branch circuit in which both poles are ungrounded.

Description

Technical Field

[0001] The present disclosure generally relates to a leakage identification system, a distribution board, a leakage identification method, and a program. More specifically, the present disclosure relates to a leakage identification system, a distribution board, a leakage identification method, and a program based on the detection result of a zero-phase current transformer provided in a main circuit.

Background Art

[0002] Patent Document 1 discloses a cutoff system provided in a main breaker housed in a distribution board cabinet. Patent Document 1 describes that the main breaker includes a leakage cutoff mechanism that turns off the contact portion when detecting a leakage state in which a leakage current flows through the contact portion. The leakage cutoff mechanism includes a zero-phase current transformer (ZCT) for detecting an unbalanced current. It is also described that the branch breaker also includes a leakage cutoff mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when a leakage occurs, it may not be easy to identify the leakage location in units of branch circuits. In particular, when the power distribution system includes a branch circuit of L1 phase - L2 phase where both poles are non-grounded poles, such as a single-phase three-wire system, it may not be easy to identify the leakage location in units of branch circuits. On the other hand, if a branch breaker equipped with a zero-phase current transformer is arranged as in Patent Document 1, it is easy to identify the leakage location in units of branch circuits. However, the zero-phase current transformer is relatively expensive. Therefore, it may not be easy in terms of introduction cost to prepare breakers equipped with zero-phase current transformers not only for the main breaker but also for the branch breakers.

[0005] This disclosure is made in view of the above-mentioned reasons and aims to provide a leakage current identification system, distribution board, leakage current identification method, and program that make it easier to identify leakage current locations at the branch circuit level while reducing the number of zero-phase current transformers. [Means for solving the problem]

[0006] A leakage current identification system according to one aspect of the present disclosure comprises a first acquisition unit, a second acquisition unit, and an identification unit. The first acquisition unit acquires leakage current detection information based on the detection result of zero-sequence current detected by a zero-sequence current transformer provided in the main circuit. The second acquisition unit acquires load current information based on the detection result of load current detected by one or more branch current detection units provided in each of a plurality of branch circuits, including at least one identification circuit. The identification unit identifies the branch circuit in which a leakage current has occurred among the plurality of branch circuits based on the leakage current detection information and the plurality of load current information relating to the plurality of branch circuits. The identification circuit is a branch circuit in which both poles are ungrounded.

[0007] A distribution board according to one aspect of the present disclosure comprises the above-described leakage current detection system, the zero-phase current transformer, a plurality of the branch current detection units, and a panel body. The panel body houses the leakage current detection system, the zero-phase current transformer, and the plurality of the branch current detection units.

[0008] A method for identifying a ground fault according to one aspect of the present disclosure comprises a first acquisition process step, a second acquisition process step, and a identification process step. In the first acquisition process step, ground fault detection information is acquired based on the detection result of zero-sequence current detected by a zero-sequence current transformer provided in the main circuit. In the second acquisition process step, load current information is acquired based on the detection result of load current detected by one or more branch current detection units provided in each of a plurality of branch circuits, including at least one identified circuit. In the identification process step, the branch circuit in which a ground fault has occurred is identified among the plurality of branch circuits based on the ground fault detection information and the plurality of load current information relating to the plurality of branch circuits. The identified circuit is a branch circuit in which both poles are ungrounded.

[0009] A program according to one aspect of this disclosure is a program that causes one or more processors to execute the above-described leakage current identification method. [Effects of the Invention]

[0010] According to this disclosure, there is an advantage in that the number of zero-phase current transformers can be reduced while making it easier to identify the location of leakage current at the branch circuit level. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a system configuration diagram including the leakage current detection system and its surrounding components according to an embodiment. [Figure 2] Figure 2 is a schematic diagram of a distribution board equipped with the same leakage current detection system, and is a schematic diagram that shows in particular how leakage current occurs in the L2 phase-N phase branch circuit. [Figure 3] Figure 3 is a schematic diagram of a distribution board equipped with the same leakage current detection system, and is a schematic diagram that shows in particular how leakage current occurs in the L1 phase-L2 phase branch circuit. [Figure 4] Figure 4 is a graph illustrating the identification process in the identification section of the leakage current identification system described above, and shows an example of current changes in zero-sequence current and load current over time. [Figure 5] Figure 5 is a flowchart illustrating the operation of the leakage current detection system described above. [Figure 6] Figure 6 is a schematic diagram of a distribution board equipped with a leakage current detection system according to Modification Example 1. [Figure 7] Figure 7 is a schematic diagram of a distribution board equipped with a leakage current detection system according to Modification Example 2. [Figure 8] Figure 8 is a conceptual diagram of a three-phase, three-wire power distribution system used to explain the leakage current detection system related to Modification 3. [Figure 9] Figure 9 is a conceptual diagram of a three-phase four-wire power distribution system used to explain the leakage current detection system according to Modification 4. [Figure 10]Figure 10 is a graph illustrating the identification process in the identification section of the leakage current identification system according to Modification 5, and shows an example of the frequency analysis results for zero-sequence current and load current. [Modes for carrying out the invention]

[0012] (overview) The following describes the leakage current detection system, distribution board, leakage current detection method, and program according to embodiments and modifications, with reference to the drawings. Note that the embodiments and modifications described below are only one of many embodiments of this disclosure. Furthermore, the embodiments and modifications described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. It is also possible to combine the configurations of the modifications as appropriate. In addition, the diagrams described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in the diagrams do not necessarily reflect the actual dimensional ratios.

[0013] As shown in Figure 1, one embodiment of the leakage current detection system 1 comprises a first acquisition unit 11, a second acquisition unit 12, and a detection unit 14. In the following description, as an example, it is assumed that multiple functions of the leakage current detection system 1 are implemented in a measurement unit 10 installed in a distribution board 100.

[0014] The first acquisition unit 11 acquires leakage detection information based on the detection result of zero-sequence current detected by the zero-sequence current transformer 2 installed in the main circuit M1. The second acquisition unit 12 acquires load current information based on the detection result of load current detected by one or more branch current detection units 3 installed in each of the multiple branch circuits B1, which include at least one specific circuit A1. The identification unit 14 identifies the branch circuit B1 in which leakage occurred based on the leakage detection information and the multiple load current information for the multiple branch circuits B1. Specific circuit A1 is a branch circuit B1 in which both poles are ungrounded. In other words, specific circuit A1 is an L1-L2 phase branch circuit in Figure 2, which shows a single-phase three-wire distribution system, where both are live phases.

[0015] According to the configuration of this leakage identification system 1, based on the leakage detection information and a plurality of load current information, the branch circuit B1 where leakage has occurred is identified. In other words, by the cooperation of the detection result of the zero-phase current transformer 2 and the detection result of the branch current detection unit 3, the leakage location is identified. Therefore, it becomes easier to suppress the necessity of providing a zero-phase current transformer in the branch circuit B1. As a result, while suppressing the number of zero-phase current transformers, it becomes easier to identify the leakage location in units of the branch circuit B1.

[0016] Also, the leakage identification method according to one aspect includes a first acquisition processing step, a second acquisition processing step, and an identification processing step. In the first acquisition processing step, leakage detection information based on the detection result of the zero-phase current detected by the zero-phase current transformer 2 provided in the main circuit M1 is acquired. In the second acquisition processing step, load current information based on the detection result of the load current detected by one or more branch current detection units 3 provided in each of a plurality of branch circuits B1 including at least one specific circuit A1 is acquired. In the identification processing step, based on the leakage detection information and the plurality of load current information regarding the plurality of branch circuits B1, the branch circuit B1 where leakage has occurred among the plurality of branch circuits B1 is identified. The specific circuit A1 is a branch circuit B1 whose both poles are non-grounded poles. Also in this leakage identification method, while suppressing the number of zero-phase current transformers, it becomes easier to identify the leakage location in units of the branch circuit B1.

[0017] This leakage identification method is used on a computer system (leakage identification system 1). That is, this leakage identification method can also be embodied by a computer program. A program according to one aspect is a program for causing one or more processors to execute the above leakage identification method. The program may be recorded on a non-temporary computer-readable recording medium. Also, a computer program product according to one aspect includes a computer program that realizes the steps of the above leakage identification method when executed by one or more processors.

[0018] (Embodiment) (1) Configuration The configuration of the leakage current detection system 1 according to this embodiment, and the configuration of the distribution board 100 equipped with the leakage current detection system 1, will be described in detail below with reference to Figures 1 to 4.

[0019] The distribution board 100 (see Figures 2 and 3) is, for example, a distribution board for a residential building, and the "user" referred to below is assumed to be a resident. However, the distribution board 100 may also be a distribution board for a non-residential building (e.g., an office building), in which case the user could be, for example, a manager who manages the office building.

[0020] As shown in Figures 2 and 3, the distribution board 100 comprises a measurement unit 10 on which all the functions of the leakage current detection system 1 are implemented, a main circuit breaker Br1 (leakage circuit breaker) having a zero-phase current transformer 2, and a plurality (five in the illustrated example) of branch circuit breakers Br2. The distribution board 100 also comprises one or more sensor boards on which a plurality (five in the illustrated example) of branch current detection units 3 are implemented, three conductive bars (main lines), and a panel body 101. The panel body 101 is configured as a cabinet that houses, for example, the measurement unit 10, the main circuit breaker Br1, the plurality of branch circuit breakers Br2, one or more sensor boards, and the three conductive bars. In other words, the distribution board 100 comprises the leakage current detection system 1, the zero-phase current transformer 2, the plurality of branch current detection units 3, and the panel body 101, and the panel body 101 houses the leakage current detection system 1, the zero-phase current transformer 2, and the plurality of branch current detection units 3.

[0021] For example, a commercial AC power grid is electrically connected to the primary side (primary side of the main breaker Br1) of a distribution board 100 installed in a house. The AC power from the grid can be transformed to 100V or 200V by a primary transformer T1 and a secondary transformer T2 (see Figures 2 and 3) in a pole-mounted transformer and supplied to the distribution board 100.

[0022] The main circuit breaker Br1 interrupts its contacts when it detects an abnormal condition. The main circuit breaker Br1 has an operating lever for manually turning the contacts on or off. Abnormal conditions include leakage current and overload current. In particular, the main circuit breaker Br1 has a zero-phase current transformer 2 (ZCT) installed in the main circuit M1 to detect leakage current occurring within the house. The zero-phase current transformer 2 detects the zero-phase current in the main circuit M1.

[0023] The main circuit breaker Br1 is a ground fault circuit breaker equipped with a tripping mechanism that shuts off the contacts in the main circuit M1 when a ground fault is detected based on the detection result of the zero-sequence current detected by the zero-sequence current transformer 2. The primary terminal of the main circuit breaker Br1 is electrically connected to the service drop wire that leads to the grid power supply. Thus, the primary terminal of the main circuit breaker Br1 is electrically connected to the grid power supply. The main circuit breaker Br1 is also electrically connected to the measurement unit 10 and inputs (transmits) ground fault detection information based on the detection result of the zero-sequence current detected by the zero-sequence current transformer 2 to the measurement unit 10.

[0024] In this embodiment, as an example, it is assumed that the leakage detection system 1 is applied to a single-phase three-wire (100V / 200V) power distribution system. A single-phase three-wire service drop line connected to the grid power supply is electrically connected to the primary terminal of the main breaker Br1. 200V power distribution is possible between the L1 phase (live phase) and the L2 phase (live phase) circuits, and 100V power distribution is possible between the L1 phase and the N phase (neutral phase) circuits, and between the L2 phase and the N phase circuits. However, there is no intention to limit the power distribution system to a single-phase three-wire system. The zero-phase current transformer 2 inside the main breaker Br1 is arranged so that the three wires of the L1 phase, L2 phase, and N phase pass through the holes of the zero-phase current transformer 2 together. In a normal state where no leakage current occurs, the magnetic fields generated by the currents flowing through the three wires, L1, L2, and N, cancel each other out, so no electromotive force is generated in the zero-sequence current transformer 2. On the other hand, suppose a ground fault current (leakage current: see the jagged arrows in Figures 2 and 3) occurs in the live phase (L phase) of a branch circuit B1. When a leakage current occurs, the balance of the currents flowing through the three wires, L1, L2, and N, is disrupted, and an electromotive force is generated in the zero-sequence current transformer 2 due to the magnetic flux generated by the difference in current values, and the zero-sequence current transformer 2 outputs a zero-sequence current indicating that a leakage current has occurred.

[0025] Three conductive bars, which constitute part of the main circuit M1, are electrically connected to the secondary terminals of the main circuit breaker Br1. The three conductive bars may include a conductive bar for the first voltage pole (L1 phase: ungrounded pole), a conductive bar for the second voltage pole (L2 phase: ungrounded pole), and a conductive bar for the neutral pole (N phase: grounded pole). Multiple (five in the illustrated example) branch circuits B1 are branched from the main line (conductive bars). In this disclosure, "branch circuit" means an individual circuit that is branched from the main line. Each of the multiple branch circuits B1 may be electrically connected to a load device that consumes power, for example, via a wiring device (such as an outlet) located in the house. Examples of load devices may include air conditioners, lighting equipment, washing machines, vacuum cleaners, cooking appliances, television receivers, and personal computers.

[0026] Multiple (five in the illustrated example) branch circuits B1 include at least one specific circuit A1. Specific circuit A1 is a branch circuit B1 with both poles being ungrounded. In the examples of single-phase three-wire distribution shown in Figures 2 and 3, specific circuit A1 corresponds to an L1-L2 phase branch circuit B1 capable of distributing 200V. In the examples of Figures 2 and 3, three of the five branch circuits B1 correspond to specific circuits A1, and the remaining two are branch circuits B1 capable of distributing 100V (with one pole being grounded).

[0027] While a detailed explanation is omitted, for example, a current sensor of the CT (Current Transformer) type may be provided as a main current detection unit to detect the current flowing through the main circuit M1. The detection result of the current sensor can be input to the measurement unit 10.

[0028] Each branch breaker Br2 is installed in the corresponding branch circuit B1 of the multiple (five) branch circuits B1. In other words, each of the multiple branch circuits B1 contains multiple branch breakers Br2. In Figures 2 and 3, branch breakers Br2 are denoted as "branch BR". The multiple branch breakers Br2 include two first branch breakers Br21, each installed in two branch circuits B1 capable of distributing 100V. The multiple branch breakers Br2 also include three second branch breakers Br22, each installed in three branch circuits B1 (specific circuits A1) capable of distributing 200V.

[0029] Each of the multiple branch circuit breakers Br2 has a primary terminal, a secondary terminal, and a contact connected to the circuit between the primary and secondary terminals. Each of the multiple branch circuit breakers Br2 further has an operating lever for manually turning the contact on or off. Each of the multiple branch circuit breakers Br2 also further has a tripping unit. The tripping unit trips (turns off) the contact when it detects an abnormal condition, such as the occurrence of an overload current.

[0030] Each branch circuit breaker Br2 does not include a zero-phase current transformer for detecting ground faults, and therefore does not have the function of shutting off contacts in response to ground fault detection.

[0031] The primary terminals of each branch breaker Br2 are electrically connected to the main line. The secondary terminals of each branch breaker Br2 can be electrically connected to the load equipment.

[0032] Each of the one or more (e.g., two) sensor boards is a printed circuit board on which one or more branch current detection units 3 are mounted. Each branch current detection unit 3 is installed to detect the current (load current) flowing through the corresponding branch circuit B1 among a plurality of branch circuits B1. In other words, the branch current detection unit 3 detects the load current input to the load equipment.

[0033] Here, one branch current detection unit 3 is provided for each branch circuit B1. Specifically, one branch current detection unit 3 is provided in either the L1 phase or L2 phase circuit, which is the ungrounded electrode in each branch circuit B1. More specifically, for an L1 phase-L2 phase branch circuit B1 (specific circuit A1) capable of 200V power distribution, the branch current detection unit 3 is provided in only one of the L1 phase or L2 phase circuits. For an L1 phase-N phase branch circuit B1 capable of 100V power distribution, the branch current detection unit 3 is provided only in the L1 phase circuit. For an L2 phase-N phase branch circuit B1 capable of 100V power distribution, the branch current detection unit 3 is provided only in the L2 phase circuit.

[0034] Each branch current detection unit 3 has, for example, a Rogowski coil type current sensor embedded in the corresponding sensor substrate. However, the type of current sensor is not particularly limited. Each branch current detection unit 3 may have either a CT type current sensor or a zero-flux type current sensor (Hall element detection type, flux gate detection type, etc.). Alternatively, each branch current detection unit 3 may have a shunt resistor and detect the current value based on the voltage drop across the shunt resistor.

[0035] Each sensor board is electrically connected to the measurement unit 10 and inputs (transmits) load current information based on the detection results of the load current detected by each branch current detection unit 3 to the measurement unit 10.

[0036] The measurement unit 10 has a measurement function that measures the main current flowing through the main circuit M1 and the current (load current) flowing through each branch circuit B1, and manages the power consumption status within the house. The measurement unit 10 is equipped with a main unit (housing). The main unit is configured to be installed inside the panel body 101 (cabinet) of the distribution board 100. The main unit may have multiple sockets into which connectors for connection lines that connect to the outside (such as the main breaker Br1 or the sensor board on which the branch current detection unit 3 is mounted) can be inserted. In this embodiment, multiple functions of the leakage current identification system 1 are provided in the measurement unit 10.

[0037] As shown in Figure 1, the leakage current detection system 1 comprises a first acquisition unit 11, a second acquisition unit 12, a third acquisition unit 13, a detection unit 14, a notification unit 15, and a storage unit 16. Note that the inclusion of the third acquisition unit 13 is not mandatory for the leakage current detection system 1, and in this embodiment, the description of the third acquisition unit 13 is omitted (it will be explained in the modified example 1 below).

[0038] The leakage current detection system 1 includes, for example, a computer system having one or more processors and memory. The computer system functions as the first acquisition unit 11, second acquisition unit 12, third acquisition unit 13, identification unit 14, and notification unit 15 in the leakage current detection system 1 by executing a program stored in memory by the processor. The program executed by the processor is pre-recorded in the memory of the computer system, but it may also be provided by being recorded on a non-temporary recording medium such as a memory card, or by being provided via a telecommunication line such as the Internet.

[0039] The first acquisition unit 11 acquires leakage detection information based on the detection result of the zero-sequence current detected by the zero-sequence current transformer 2 installed in the main circuit M1. The measurement unit 10 is electrically connected to the main circuit breaker Br1 which has the zero-sequence current transformer 2 and has the function of communicating with the main circuit breaker Br1, and the first acquisition unit 11 acquires leakage detection information from the main circuit breaker Br1. The first acquisition unit 11 is assumed to acquire the detection result of the zero-sequence current (leakage detection information) from the main circuit breaker Br1 at any time, regardless of whether there is a leakage current or not. However, the first acquisition unit 11 may acquire the detection result of the zero-sequence current (leakage detection information) from the main circuit breaker Br1 only when a leakage current is detected by the main circuit breaker Br1.

[0040] The second acquisition unit 12 acquires load current information based on the detection results of load currents detected by one or more branch current detection units 3 provided in each of the multiple (five in this case) branch circuits B1, which include at least one (three in this case) specific circuit A1. The measurement unit 10 is electrically connected to one or more (e.g., two) sensor boards equipped with Rogowski coil type current sensors (branch current detection units 3), and has the function of communicating with each sensor board. As described above, one branch current detection unit 3 is provided for each branch circuit B1. As a result, the second acquisition unit 12 acquires five load current information corresponding to each of the five branch circuits B1 from one or more sensor boards. The second acquisition unit 12 is assumed to acquire the load current detection results (load current information) from the sensor boards at any time, regardless of whether or not there is a ground fault. However, the second acquisition unit 12 may acquire the load current detection results (load current information) from the sensor boards triggered by the detection of a ground fault.

[0041] The memory unit 16 is, for example, an electrically rewritable non-volatile semiconductor memory such as flash memory. The memory unit 16 stores (stores) historical information such as leakage current detection information and load current information. The memory unit 16 also stores (stores) historical information of the identification results in the identification unit 14.

[0042] The identification unit 14 performs an identification process to identify the branch circuit B1 where a ground fault occurred, based on the ground fault detection information and the load current information of the multiple (five in this case) branch circuits B1. The identification process can be automatically executed as a trigger when a ground fault is detected based on the ground fault detection information from the main breaker Br1. Alternatively, the identification process may be executed in response to an operation input to the operation unit 10, an operation input to the controller C1, or an operation input to the information terminal D1. In other words, the identification process may be executed, for example, when a user who has learned that a ground fault has been detected due to a contact interruption at the main breaker Br1 performs an operation input at any time of their choosing.

[0043] Regarding the specific processing, for example, as shown in Figure 4, the identification unit 14 identifies the timing of the leakage current occurrence (time t1 in Figure 4) from the leakage current detection information. The upper part of Figure 4 shows an example of the current change over time of the zero-sequence current detected by the zero-sequence current transformer 2 of the main circuit breaker Br1 as leakage current detection information. The vertical axis in the upper part of Figure 4 shows the zero-sequence current [mA]. ​​The lower part of Figure 4 shows an example of the current change over time of the current sensor output detected by the branch current detection unit 3 corresponding to a certain branch circuit B1 as load current information. The current sensor output is the output corresponding to the load current flowing through the branch circuit B1. The vertical axis in the lower part of Figure 4 shows the current sensor output (labeled "load current" in Figure 4) [A]. The identification unit 14 determines whether or not there is a sudden branch current fluctuation occurring at the same timing as the occurrence timing (time t1) in the multiple load current information related to multiple branch circuits B1. The identification unit 14 determines that branch circuit B1, which has load current information indicating a rapid branch current fluctuation, is branch circuit B1 where a ground fault has occurred, if there is a rapid branch current fluctuation. For example, the identification unit 14 determines that there is a rapid branch current fluctuation if the rate of change of the load current per predetermined time in the load current information is equal to or greater than a specified rate of change (threshold). Information on the specified rate of change (threshold) is stored in advance in the storage unit 16.

[0044] In the example shown in Figure 4, a sudden fluctuation in branch current occurs at the same time as the leakage current occurrence (time t1) in the load current information corresponding to a certain branch circuit B1. Therefore, the identification unit 14 determines that the branch circuit B1 in question is the location where the leakage current occurred.

[0045] Incidentally, ground faults can occur not in the neutral phase (N phase) circuit, but in the live phase, either the L1 or L2 phase circuit. Therefore, for example, in the L2 phase-N phase branch circuit B1 shown on the lower left of the main circuit M1 in Figure 2, it is sufficient to have the branch current detection unit 3 in the L2 phase circuit, and problems are unlikely to occur even if the branch current detection unit 3 is not placed in the N phase circuit. That is, as shown in Figure 2, if a ground fault causes a ground fault in the L2 phase circuit, a sudden fluctuation in branch current may appear in the load current information corresponding to the branch current detection unit 3. Similarly, in the L1 phase-N phase branch circuit B1 shown on the upper left of the main circuit M1 in Figure 2, it is sufficient to have the branch current detection unit 3 in the L1 phase circuit, and problems are unlikely to occur even if the branch current detection unit 3 is not placed in the N phase circuit.

[0046] Furthermore, as shown in Figures 2 and 3, in specific circuit A1, the branch current detection unit 3 is provided for only one of the two poles (both ungrounded poles). Therefore, as in specific circuit A1 shown in the center of the lower row below the main line in Figure 3, if the branch current detection unit 3 is located only in the L2 phase circuit, a sudden change in branch current may appear in the load current information corresponding to the branch current detection unit 3 if a ground fault occurs in the L2 phase circuit. However, as shown in Figure 3, if a ground fault occurs in the other L1 phase circuit where the branch current detection unit 3 is not located, a sudden change in branch current may not appear in the load current information corresponding to the branch current detection unit 3 located in the L2 phase circuit.

[0047] Therefore, in this embodiment, the identification unit 14 determines that the specific circuit A1 is the branch circuit B1 where the leakage current occurred if there is no sudden branch current fluctuation in the multiple load current information. In other words, if a leakage current is detected but there is no sudden branch current fluctuation in the multiple load current information, the identification unit 14 determines that the location of the leakage current is not the L1-N phase branch circuit B1 or the L2-N phase branch circuit B1.

[0048] Furthermore, if multiple branch circuits B1 contain only one specific circuit A1, and there are no sudden branch current fluctuations in multiple load current information despite a ground fault being detected, the identification unit 14 will determine that the single specific circuit A1 is the location of the ground fault. However, if there are two or more specific circuits A1, the identification unit 14 can determine that the location of the ground fault is not the L1-N phase branch circuit B1 or the L2-N phase branch circuit B1, but it cannot determine which of the two or more specific circuits A1 the ground fault occurred in.

[0049] In this case, when the user receives a notification from the notification unit 15 (described later) stating "a ground fault has occurred in one of the specific circuits A1", they can manually narrow down which specific circuit A1 the ground fault occurred in by actually operating the lever of the branch breaker Br2 on the distribution board 100. Hereafter, this operation may be referred to as the "narrowing operation".

[0050] Specifically, with the main circuit breaker Br1's contacts turned off due to ground fault detection, the user first operates the control lever to switch the contacts of the second branch circuit breakers Br22 in all specific circuits A1 from on to off. Then, the user operates the control lever of the main circuit breaker Br1 to switch its contacts from off to on, and then sequentially switches the contacts of each second branch circuit breaker Br22 in each specific circuit A1 from off to on. The moment the contact of the second branch circuit breaker Br22 in the specific circuit A1 where the ground fault is actually occurring switches from off to on, the main circuit breaker Br1 will detect the ground fault again and shut off the main circuit M1. As a result, the user can narrow down the location of the ground fault on a branch circuit B1 basis. However, a prerequisite for narrowing down the location of the ground fault is that the ground fault that occurred is a reproducible and persistent ground fault. For example, if a person steps on a cable or similar object, causing a temporary short circuit, and the short circuit disappears the moment the person stops stepping on the cable or object, then that short circuit can be described as a non-reproducible short circuit.

[0051] The notification unit 15 notifies the user of the identification result made by the identification unit 14. The notification unit 15 has a communication interface for wirelessly communicating with, for example, a HEMS (Home Energy Management System) controller C1 (see Figure 1) installed in the home. The notification unit 15 may also have a communication interface for wirelessly communicating with the user's information terminal D1 (see Figure 1). Here, the information terminal D1 is assumed to be a smartphone carried by the user, but is not limited to a smartphone. The information terminal D1 may be a tablet terminal or a laptop computer, or a desktop computer. Dedicated application software for communicating with the notification unit 15 is pre-installed on both the controller C1 and the information terminal D1.

[0052] The notification unit 15 can communicate wirelessly with the controller C1 and the information terminal D1 directly or via a router installed in the home. Furthermore, if the information terminal D1 is located outside the home, the notification unit 15 may have a communication interface for communicating with the information terminal D1 via a router in the home and a wide-area network such as the Internet. Wireless communication may be wireless communication conforming to standards such as Wi-Fi®, Bluetooth®, ZigBee®, or unlicensed low-power wireless (specified low-power wireless). Also, the communication method is not limited to wireless communication and may include wired communication in at least some of the communications.

[0053] As information of the notification result from the specific unit 14, a notification message including that a ground fault has been detected in the house and the branch circuit B1 (candidate) identified as the location of the ground fault may be displayed (notified) from the monitor of the controller C1 or the display unit of the information terminal D1. The notification message may also be notified by voice output from the speaker of the controller C1 or the information terminal D1.

[0054] For example, the notification unit 15 notifies the user of the circuit number of the branch circuit B1 where the ground fault occurred, as information of the identification result identified by the identification unit 14, from the controller C1 and / or the information terminal D1. In other words, the measurement unit 10 (ground fault identification system 1) manages the circuit number information of each branch circuit B1. The circuit number information is stored in advance in the storage unit 16, etc. In some cases, the circuit number is managed in association with the name of the load equipment or the name of the room where wiring devices such as outlets are installed. In that case, the notification unit 15 may notify the user of the name of the associated load equipment, such as "washing machine," or the name of the room, such as "living room," instead of (or in addition to) the circuit number of the branch circuit B1 where the ground fault occurred.

[0055] As described above, if multiple branch circuits B1 include two or more specific circuits A1, the identification unit 14 may not be able to pinpoint which specific circuit A1 is experiencing a ground fault. The identification unit 14 may notify that a ground fault has occurred in any of the two or more specific circuits A1. For example, suppose the circuit number of the L1-N phase branch circuit B1 is "1", the circuit number of the L2-N phase branch circuit B1 is "2", and the circuit numbers of the three specific circuits A1 are "3" to "5". The identification unit 14 may notify that a ground fault has occurred in any of the branch circuits B1 with circuit numbers "3" to "5". Alternatively, the identification unit 14 may notify that a ground fault has occurred in any of the branch circuits B1 with circuit numbers other than "1" and "2".

[0056] (2) Operation Instructions The operation of the leakage current detection system 1 will be explained below with reference to the flowchart shown in Figure 5. Note that the flowchart shown in Figure 5 is merely one example of the operation flow for the leakage current detection system 1, and the order of processing may be changed as appropriate, or processing may be added or omitted as appropriate.

[0057] The leakage current detection system 1 acquires leakage current detection information from the main circuit breaker Br1 based on the detection result of the zero-sequence current detected by the zero-sequence current transformer 2 installed in the main circuit M1 (Step ST1: Execution of the first acquisition process). The leakage current detection system 1 also acquires load current information from the sensor board based on the detection result of the load current detected by the branch current detection unit 3 installed in each of the multiple branch circuits B1 (Step ST2: Execution of the second acquisition process).

[0058] The leakage current identification system 1 performs an identification process to identify the branch circuit B1 where the leakage current occurred, based on leakage current detection information and multiple load current information related to multiple branch circuits B1. In the identification process, the leakage current identification system 1 identifies the timing of the leakage current occurrence (time t1 in Figure 4) from the leakage current detection information (step ST3). Then, the leakage current identification system 1 determines whether or not there is a sudden branch current fluctuation occurring at the same timing as this occurrence timing in the multiple load current information (step ST4). If there is a sudden branch current fluctuation (step ST4: Yes), the identification unit 14 determines branch circuit B1, which has load current information indicating a sudden branch current fluctuation, as the location of the leakage current (step ST5). On the other hand, if there is no sudden branch current fluctuation (step ST4: No), the identification unit 14 determines the identification circuit A1 as the location of the leakage current (step ST6).

[0059] The leakage current identification system 1 then transmits the results identified in the identification process (location of the leakage current) to the controller C1 and / or information terminal D1 to notify the user (step ST7: execution of notification process). As a result, the user can find out which branch circuit B1 (candidate) is the location of the leakage current.

[0060] (3) Advantages As described above, according to the leakage current identification system 1 of this embodiment, the branch circuit B1 where a leakage current has occurred is identified based on leakage current detection information and multiple load current information. In other words, the location of the leakage current is identified through the coordination of the detection result of the zero-phase current transformer 2 and the detection result of the branch current detection unit 3. Therefore, it becomes easier to reduce the need to install relatively expensive zero-phase current transformers in branch circuits B1. As a result, it becomes easier to identify the location of the leakage current on a branch circuit B1 basis while keeping the number of zero-phase current transformers down. In addition, the cost of introducing the distribution board 100 can be reduced.

[0061] Furthermore, the identification unit 14 identifies the timing of the leakage current occurrence from the leakage current detection information and determines whether there is a sudden branch current fluctuation occurring at the same timing as the occurrence timing in multiple load current information. The identification unit 14 then determines that branch circuit B1, which shows a sudden branch current fluctuation in the load current information, is the branch circuit B1 where the leakage current occurred. As a result, the reliability of the accuracy in identifying the location of the leakage current is improved.

[0062] In particular, as in this embodiment, each specific circuit A1 may be provided with a branch current detection unit 3 for only one of the poles of either the L1 phase or the L2 phase. The identification unit 14 determines that specific circuit A1 is the branch circuit B1 where a ground fault has occurred if there are no sudden fluctuations in branch current in the multiple load current information. Therefore, the reliability of the accuracy of identifying the location of the ground fault is improved. In other words, it becomes easier to reduce the need to provide a branch current detection unit 3 for each of the L1 phase and L2 phase in each specific circuit A1, and in this respect, the introduction cost of the distribution board 100 can be reduced.

[0063] Furthermore, if there are two or more specific circuits A1, and there is no sudden fluctuation in branch current despite a ground fault being detected, the identification unit 14 may not be able to determine which of the two or more specific circuits A1 the ground fault occurred in. However, the identification unit 14 can at least determine that the location of the ground fault is not the L1-N phase branch circuit B1 or the L2-N phase branch circuit B1. Therefore, when the user performs the above narrowing down procedure, they only need to sequentially operate the operating levers of the second branch breakers Br22 of the two or more specific circuits A1, which can be helpful in the narrowing down procedure.

[0064] (4) Variations The following lists some modifications. Each modification described below can be applied in appropriate combination with the above embodiment or other modifications. In the descriptions of each modification below, components similar to those in the leakage current detection system 1 and distribution board 100 according to the above embodiment may be given the same reference numerals, and their detailed descriptions may be omitted.

[0065] (4.1) Variation 1 The following description will explain a distribution board 100 equipped with a leakage current identification system 1 according to Modification 1, with reference to Figure 6.

[0066] In the distribution board 100 according to Modification 1, as shown in Figure 6, one or more main current detection units 4 are provided in the main circuit M1. In the example in Figure 6, a main current detection unit 4 is provided in each of the L1 phase circuit and the L2 phase circuit in the main circuit M1. Each main current detection unit 4 includes, for example, a CT type current sensor, but the type of current sensor is not particularly limited.

[0067] Furthermore, the leakage current identification system 1 according to Modification 1 includes a third acquisition unit 13 (see Figure 1). The third acquisition unit 13 acquires main current information based on the detection results of the main current detected by one or more main current detection units 4 provided in the main circuit M1. In Modification 1 as well, the identification circuit A1 is provided with a branch current detection unit 3 for only one of the two poles.

[0068] The identification unit 14 in Modification 1 identifies the timing of the leakage current from the leakage current detection information and determines whether there is a sudden branch current fluctuation occurring at the same timing as the leakage current in multiple load current information (first determination process). Furthermore, the identification unit 14 in Modification 1 also determines whether there is a sudden main current fluctuation occurring at the same timing as the leakage current in the main current information (second determination process). If there is no sudden branch current fluctuation in multiple load current information, and there is a sudden main current fluctuation in the main current information, the identification unit 14 determines that the specific circuit A1 is the branch circuit B1 where the leakage current occurred. The execution of the second determination process improves the accuracy of the determination that a leakage current has occurred in the specific circuit A1.

[0069] Furthermore, the identification unit 14 may, for example, execute the first determination process first, and if there are no sudden branch current fluctuations in the multiple load current information, then execute the second determination process. The identification unit 14 may, for example, execute the first determination process first, and if there are sudden branch current fluctuations in the multiple load current information, skip the execution of the second determination process.

[0070] According to the configuration of Modified Example 1, the location of the leakage current is identified by the coordination of the detection results of the zero-phase current transformer 2, the branch current detection unit 3, and the main current detection unit 4. Therefore, the reliability of the accuracy in identifying the location of the leakage current is further improved.

[0071] (4.2) Modification 2 The following describes a distribution board 100 equipped with a leakage current identification system 1 according to modified example 2, with reference to Figure 7.

[0072] In the distribution board 100 according to Modification 2, as shown in Figure 7, a branch current detection unit 3 is provided for each of the poles of a specific circuit A1. In other words, in the example in Figure 7, a branch current detection unit 3 is provided for each of the live phases, L1 and L2, in each of the three specific circuits A1. In this case, the load current information for each specific circuit A1 includes information on the load currents flowing through the L1 and L2 phases, respectively.

[0073] The specific unit 14 in the modified example 2 identifies the timing of the leakage current occurrence from the leakage current detection information and determines whether there is a sudden branch current fluctuation occurring at the same timing as the leakage current occurrence in multiple load current information.

[0074] According to the configuration of Modified Example 2, if a ground fault occurs in any branch circuit B1, even if it is a specific circuit A1, the likelihood of detecting a sudden branch current fluctuation in the load current information is higher than in the configuration of the above embodiment. In other words, unlike the configuration of the above embodiment, the configuration of Modified Example 2 makes it less likely that the problem of not being able to identify which specific circuit A1 is experiencing the ground fault when there are two or more specific circuits A1 is reduced. As a result, the reliability of the accuracy of identifying the location of the ground fault is further improved. In addition, it becomes more likely that the user will not have to perform the narrowing-down work required to pinpoint the location of the ground fault.

[0075] (4.3) Modification example 3 The following describes a distribution board 100 equipped with a leakage current identification system 1 according to Modification 3, with reference to Figure 8.

[0076] In the above embodiment, the case where the power distribution system is a single-phase three-wire system was given as an example. In Modification 3, as shown in Figure 8, the power distribution system is a three-phase three-wire system. In other words, the leakage current detection system 1 in this disclosure is also applicable to a three-phase three-wire power distribution system. Although the panel body 101 of the distribution board 100 is not shown in Figure 8, the main breaker Br1 and multiple (for example, three) branch breakers Br2 shown in Figure 8 are housed in the panel body 101 of the distribution board 100 according to Modification 3.

[0077] In Modification 3, as an example, the multiple branch circuits B1 include an R-phase to S-phase branch circuit B1 capable of 200V distribution, an S-phase to T-phase branch circuit B1 capable of 200V distribution, and an R-phase to T-phase branch circuit B1 capable of 200V distribution. In a three-phase three-wire system, the R-phase, S-phase, and T-phase are all ungrounded live phases, so all branch circuits B1 in Modification 3 correspond to specific circuits A1. In Modification 3, the zero-phase current transformer 2 in the main breaker Br1 is arranged so that the three wires of the R-phase, S-phase, and T-phase pass through the hole in the zero-phase current transformer 2 together. In Modification 3, a branch breaker Br2 is provided for each of the R-phase to S-phase, S-phase to T-phase, and R-phase to T-phase branch circuits B1.

[0078] In the distribution board 100 according to Modification 3, similar to Modification 2, a branch current detection unit 3 is provided for each of the poles in the specific circuit A1. That is, in the example of Figure 8, a branch current detection unit 3 is provided for each of the R-phase and S-phase circuits in the R-phase to S-phase specific circuit A1. Also, a branch current detection unit 3 is provided for each of the S-phase and T-phase circuits in the S-phase to T-phase specific circuit A1. Furthermore, a branch current detection unit 3 is provided for each of the R-phase and T-phase circuits in the R-phase to T-phase specific circuit A1.

[0079] The load current information for a specific circuit A1 consisting of R-phase and S-phase includes information on the load current flowing through the R-phase and S-phase respectively. The load current information for a specific circuit A1 consisting of S-phase and T-phase includes information on the load current flowing through the S-phase and T-phase respectively. The load current information for a specific circuit A1 consisting of R-phase and T-phase includes information on the load current flowing through the R-phase and T-phase respectively.

[0080] The identification unit 14 in the modified example 3 identifies the timing of the leakage current occurrence from the leakage current detection information. The identification unit 14 determines whether there is a sudden branch current fluctuation occurring at the same timing as the leakage current occurrence timing in the multiple load current information related to the R-phase-S-phase, S-phase-T-phase and R-phase-T-phase specific circuit A1.

[0081] According to the configuration of Modification 3, even when the leakage current identification system 1 is applied to a three-phase three-wire distribution system, it becomes easier to identify the leakage current location at the branch circuit B1 level while keeping the number of zero-phase current transformers low.

[0082] In particular, in a three-phase three-wire power distribution system, a branch current detection unit 3 is provided for each pole of every specific circuit A1, increasing the likelihood of detecting sudden branch current fluctuations. In other words, the configuration according to Modification 3 makes it less likely that the problem of not being able to identify which specific circuit A1 is experiencing a ground fault will occur. As a result, the reliability of the accuracy in identifying the location of the ground fault is further improved. In addition, it becomes less likely that the user will have to perform the narrowing-down work required to pinpoint the location of the ground fault.

[0083] (4.4) Modification 4 The following description will explain the distribution board 100 equipped with the leakage current identification system 1 according to Modification 4, with reference to Figure 9.

[0084] In the above embodiment, the case where the power distribution system is a single-phase three-wire system is given as an example, and in the above modification 3, the case where the power distribution system is a three-phase three-wire system is given as an example. In modification 4, as shown in Figure 9, the power distribution system is a three-phase four-wire system. In other words, the leakage current detection system 1 in this disclosure is also applicable to a three-phase four-wire power distribution system. Although the panel body 101 of the distribution board 100 is not shown in Figure 9, the main breaker Br1 and multiple (for example, four) branch breakers Br2 shown in Figure 9 are housed in the panel body 101 of the distribution board 100 according to modification 4.

[0085] In Modification 4, as an example, the multiple branch circuits B1 include an R-phase to N-phase branch circuit B1 capable of distributing 240V, an R-phase to S-phase branch circuit B1 capable of distributing 415V, an S-phase to T-phase branch circuit B1 capable of distributing 415V, and an R-phase to T-phase branch circuit B1 capable of distributing 415V. In a three-phase four-wire system, only the N phase is the neutral phase with the grounded electrode, while the remaining three phases, R, S, and T, are live phases with ungrounded electrodes. In Modification 4, of the four branch circuits B1, three—the R-phase to S-phase branch circuit B1, the S-phase to T-phase branch circuit B1, and the R-phase to T-phase branch circuit B1—correspond to specific circuits A1. In Modification 4, the zero-phase current transformer 2 inside the main breaker Br1 is arranged so that the four wires of the N phase, R phase, S phase, and T phase all pass through the hole in the zero-phase current transformer 2 together. In modified example 4, a branch breaker Br2 is provided for each of the four branch circuits B1.

[0086] In the distribution board 100 according to Modification 4, branch current detection units 3 are provided for each of the two poles in the three specific circuits A1. That is, in the example in Figure 9, branch current detection units 3 are provided for each of the R-phase and S-phase circuits in the R-phase to S-phase specific circuit A1. Also, branch current detection units 3 are provided for each of the S-phase and T-phase circuits in the S-phase to T-phase specific circuit A1. Furthermore, branch current detection units 3 are provided for each of the R-phase and T-phase circuits in the R-phase to T-phase specific circuit A1. Note that in the R-phase to N-phase branch circuit B1, branch current detection units 3 are provided only in the R-phase circuit, and not in the N-phase circuit.

[0087] The load current information for specific circuit A1 (R-S phase) includes information on the load current flowing through the R phase and the S phase. The load current information for specific circuit A1 (S-T phase) includes information on the load current flowing through the S phase and the T phase. The load current information for specific circuit A1 (R-T phase) includes information on the load current flowing through the R phase and the T phase. The load current information for branch circuit B1 (R-N phase) includes only information on the load current flowing through the R phase.

[0088] The identification unit 14 in the modified example 4 identifies the timing of the leakage current occurrence from the leakage current detection information. The identification unit 14 determines whether there is a sudden branch current fluctuation occurring at the same timing as the leakage current occurrence timing in the multiple load current information related to the branch circuit B1 of R phase-N phase, R phase-S phase, S phase-T phase and R phase-T phase.

[0089] According to the configuration of Modified Example 4, even when the leakage current identification system 1 is applied to a three-phase four-wire distribution system, it becomes easier to identify the leakage current location at the branch circuit B1 level while keeping the number of zero-phase current transformers low.

[0090] In particular, in a three-phase four-wire power distribution system, a branch current detection unit 3 is provided for each of the poles in the three specific circuits A1, increasing the likelihood of detecting sudden branch current fluctuations. In other words, according to the configuration of Modified Example 4, the problem of not being able to identify which specific circuit A1 is experiencing a ground fault becomes less likely. As a result, the reliability of the accuracy in identifying the location of the ground fault is further improved. In addition, it becomes more likely that the user will not have to perform the narrowing-down work required to pinpoint the location of the ground fault.

[0091] (4.5) Modification 5 The following describes the leakage current identification system 1 related to Modification 5, with reference to Figure 10.

[0092] The identification unit 14 of the leakage current identification system 1 according to Modified Example 5 compares the frequency components of the current with the leakage current detection information and the load current information for the multiple branch circuits B1 to identify the branch circuit B1 where a leakage current occurred. The identification unit 14 according to Modified Example 5 has the function of performing an FFT (fast Fourier transform) on the current change over time of the zero-sequence current in the leakage current detection information. The identification unit 14 also has the function of performing an FFT on the current change over time of the load current in each of the multiple load current information.

[0093] Figure 10 shows an example of the FFT results for the ZCT output (zero-sequence current) in the upper panel and an example of the FFT results for the current sensor output (load current) (in a branch circuit B1) in the lower panel. In Figure 10, the first frequency f1, which is the frequency of the commercial AC power supply, and the second frequency f2, which is a frequency component higher than the first frequency f1, are illustrated.

[0094] The identification unit 14 identifies a second frequency f2 (peak frequency) in the leakage detection information that is higher in frequency than the first frequency f1. In other words, the identification unit 14 identifies the second frequency f2 that appears as a peak frequency at a higher frequency than the first frequency f1 in the zero-sequence current as the frequency caused by the leakage. The identification unit 14 determines whether or not there are peak frequencies matching this second frequency f2 in the multiple load current information. As shown in Figure 10, if there is a current sensor output showing a peak frequency that matches the second frequency f2 (peak frequency) of the zero-sequence current, the identification unit 14 determines that the branch circuit B1 corresponding to that load current information is the location of the leakage.

[0095] Even with a configuration that identifies the location of a leakage current by comparing the frequency components of the current, as in Modification 5, it is possible to identify the location of the leakage current at the branch circuit B1 level while keeping the number of zero-phase current transformers low, similar to the case in the above embodiment where the location of the leakage current is identified by rapid branch current fluctuations. In addition, the identification unit 14 may also identify the location of the leakage current by performing both the determination of the presence or absence of rapid branch current fluctuations in the above embodiment and the comparison of the frequency components of the current in Modification 5, in which case the reliability of the accuracy of identifying the location of the leakage current will be further improved.

[0096] (4.6) Variation 6 The following describes the leakage current identification system 1 related to the modified example 6.

[0097] In the above embodiment, the specific unit 14 determines, for example, that there is a sudden branch current fluctuation if the rate of change of the load current per predetermined time in the load current information is equal to or greater than a specified rate of change (threshold). However, the branch current fluctuation of the load current flowing through each branch circuit B1 may differ depending on the type of load equipment electrically connected to the branch circuit B1. Therefore, depending on the type of connected load equipment, even if there is a sudden branch current fluctuation, it may not be a current fluctuation caused by a ground fault, but rather a current fluctuation that can occur during the normal operation of the load equipment (for example, a current fluctuation that occurs when a washing machine starts up).

[0098] The identification unit 14 of the leakage current identification system 1 according to Modification 6 has a function to estimate the type of load equipment. In the identification process, the identification unit 14 extracts, for example, the current value and fluctuation pattern of the load current from the load current information, and estimates the type of load equipment based on the extraction results (load estimation process). The load estimation process may be performed using a correspondence table that links multiple current values ​​and fluctuation patterns to multiple types of load equipment, but here, for example, it is assumed that machine learning is used. That is, the identification unit 14 estimates the type of load equipment using a trained model generated by a machine learning algorithm using artificial intelligence (AI). The identification unit 14 inputs the current values ​​and fluctuation patterns extracted from the load current information into the trained model, and estimates the type of load equipment based on the results output from the trained model (for example, a result that the probability of the type of load equipment being a "washing machine" is 90%).

[0099] In this disclosure, "trained model" refers to a model in which machine learning using training data has been completed. Here, a trained model is a model in which machine learning using supervised learning has been completed. A trained model is generated (constructed) using a large amount of training data in which data such as current values ​​and fluctuation patterns are labeled with the type of load equipment corresponding to them.

[0100] The term "trained model" is assumed to include, for example, models using neural networks, or models generated by deep learning using multi-layer neural networks. Neural networks may include, for example, CNNs (Convolutional Neural Networks) or BNNs (Bayesian Neural Networks). The trained model is implemented by mounting the trained neural network on an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array). The term "trained model" is not limited to models generated by deep learning. The trained model may also be a model generated by a support vector machine or a decision tree.

[0101] The memory unit 16 in the modified example 6 stores in advance multiple rate of change (thresholds) corresponding to multiple types of load equipment. That is, the memory unit 16 stores in advance, for example, a rate of change (threshold) corresponding to lighting equipment, a rate of change (threshold) corresponding to air conditioning equipment, and a rate of change (threshold) corresponding to washing machines. The identification unit 14 uses the rate of change (threshold) corresponding to the estimated type of load equipment to determine whether or not there is a sudden change in branch current relative to the load current information.

[0102] According to the configuration of Modified Example 6, the possibility of mistakenly identifying branch current fluctuations that may occur during the normal operation of load equipment as sudden branch current fluctuations caused by a ground fault can be reduced. As a result, the reliability of the accuracy in identifying the location of the ground fault is further improved.

[0103] (4.7) Other variations Functions similar to the leakage current identification system 1 according to the above embodiment may be embodied in a leakage current identification method, a computer program, or a non-temporary recording medium on which a computer program is recorded.

[0104] The leakage current detection system 1 in this disclosure includes a computer system. The computer system mainly consists of a processor and memory as hardware. The functionality of the leakage current detection system 1 in this disclosure is realized by the execution of a program recorded in the memory of the computer system by the processor. The program may be pre-recorded in the memory of the computer system, provided via a telecommunication line, or provided on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system. The processor of the computer system consists of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). The integrated circuits such as ICs or LSIs referred to here are named differently depending on the degree of integration, and include integrated circuits called system LSIs, VLSIs (Very Large Scale Integration), or ULSIs (Ultra Large Scale Integration). Furthermore, FPGAs (Field-Programmable Gate Arrays) that are programmed after the manufacture of the LSI, or logic devices that allow for the reconfiguration of junction relationships or circuit compartments within the LSI, can also be used as processors. Multiple electronic circuits may be integrated onto a single chip or distributed across multiple chips. Multiple chips may be integrated onto a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller also consists of one or more electronic circuits, including semiconductor integrated circuits or large-scale integrated circuits.

[0105] Furthermore, it is not essential that the multiple functions of the leakage current detection system 1 be integrated into a single housing. For example, the components of the leakage current detection system 1 may be distributed across multiple housings.

[0106] Conversely, as in the above embodiment, multiple functions in the leakage current detection system 1 may be integrated into a single housing. Furthermore, at least some of the functions of the leakage current detection system 1, for example, some of the functions of the leakage current detection system 1, may be implemented by the cloud (cloud computing), etc.

[0107] In the above embodiment, all of the functions of the leakage current detection system 1 are provided in the measurement unit 10, but at least some of the functions of the leakage current detection system 1 may be provided in a device other than the measurement unit 10 (for example, the HEMS controller C1).

[0108] In the above embodiment, the measurement unit 10 is housed inside the panel body 101 of the distribution board 100, but the measurement unit 10 may also be installed outside the panel body 101 (for example, in a form that is attached externally to the side of the panel body 101).

[0109] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0110] The leakage current identification system (1) according to the first embodiment comprises a first acquisition unit (11), a second acquisition unit (12), and an identification unit (14). The first acquisition unit (11) acquires leakage current detection information based on the detection result of zero-sequence current detected by a zero-sequence current transformer (2) installed in the main circuit (M1). The second acquisition unit (12) acquires load current information based on the detection result of load current detected by one or more branch current detection units (3) installed in each of a plurality of branch circuits (B1) including at least one identification circuit (A1). The identification unit (14) identifies the branch circuit (B1) in which leakage current has occurred among the plurality of branch circuits (B1) based on the leakage current detection information and the plurality of load current information relating to the plurality of branch circuits (B1). The identification circuit (A1) is a branch circuit (B1) in which both poles are ungrounded.

[0111] According to the above configuration, the number of zero-phase current transformers can be kept to a minimum, while making it easier to identify leakage points at the branch circuit (B1) level.

[0112] With respect to the leakage current identification system (1) according to the second embodiment, in the first embodiment, the identification unit (14) identifies the timing of leakage current occurrence from leakage current detection information. The identification unit (14) determines whether there is a sudden branch current fluctuation occurring at the same timing as the occurrence timing in the multiple load current information for multiple branch circuits (B1). If there is a sudden branch current fluctuation, the identification unit (14) determines that the branch circuit (B1) with load current information showing the sudden branch current fluctuation is the branch circuit (B1) where the leakage current occurred.

[0113] According to the above embodiment, the reliability of the accuracy in identifying the location of electrical leakage is improved.

[0114] With respect to the leakage current identification system (1) according to the third embodiment, in the second embodiment, the identification circuit (A1) is provided with a branch current detection unit (3) for only one of the two poles. The identification unit (14) determines that the identification circuit (A1) is the branch circuit (B1) where a leakage current has occurred if there is no sudden branch current fluctuation in the multiple load current information.

[0115] According to the above embodiment, the reliability of the accuracy in identifying the location of electrical leakage is further improved.

[0116] The leakage current identification system (1) according to the fourth embodiment further comprises a third acquisition unit (13) in the second embodiment. The third acquisition unit (13) acquires main current information based on the detection results of the main current detected by one or more main current detection units (4) provided in the main circuit (M1). The identification circuit (A1) is provided with a branch current detection unit (3) for only one of the two poles. The identification unit (14) determines in the main current information whether or not there is a sudden main current fluctuation occurring at the same timing as the occurrence timing. If there is no sudden branch current fluctuation in the multiple load current information, and there is a sudden main current fluctuation in the main current information, the identification unit (14) determines that the identification circuit (A1) is the branch circuit (B1) where the leakage current occurred.

[0117] According to the above embodiment, the reliability of the accuracy in identifying the location of electrical leakage is further improved.

[0118] With respect to the fifth embodiment of the leakage current detection system (1), in the second embodiment, the detection circuit (A1) is provided with a branch current detection unit (3) for each of the two poles.

[0119] According to the above embodiment, the reliability of the accuracy in identifying the location of electrical leakage is further improved.

[0120] With respect to the sixth embodiment of the leakage current identification system (1), in any one of the first to fifth embodiments, the identification unit (14) compares the frequency components of the current with the leakage current detection information and the load current information of the multiple branch circuits (B1) to identify the branch circuit (B1) in which a leakage current occurred among the multiple branch circuits (B1).

[0121] According to the above embodiment, the reliability of the accuracy in identifying the location of electrical leakage is further improved.

[0122] The leakage current identification system (1) according to the seventh embodiment further comprises a notification unit (15) that notifies the identification result by the identification unit (14) in any one of the first to sixth embodiments.

[0123] According to the above embodiment, the user can know the result of the identification by the identification unit (14), thus improving user convenience.

[0124] The distribution board (100) according to the eighth embodiment comprises a leakage current detection system (1) according to any one of the first to seventh embodiments, a zero-phase current transformer (2), a plurality of branch current detection units (3), and a panel body (101). The panel body (101) houses the leakage current detection system (1), the zero-phase current transformer (2), and the plurality of branch current detection units (3).

[0125] According to the above embodiment, it is possible to provide a distribution board (100) that makes it easier to identify leakage points at the branch circuit (B1) level while keeping the number of zero-phase current transformers low.

[0126] The leakage current identification method according to the ninth embodiment comprises a first acquisition processing step, a second acquisition processing step, and an identification processing step. In the first acquisition processing step, leakage current detection information is acquired based on the detection result of zero-sequence current detected by a zero-sequence current transformer (2) provided in the main circuit (M1). In the second acquisition processing step, load current information is acquired based on the detection result of load current detected by one or more branch current detection units (3) provided in each of a plurality of branch circuits (B1) including at least one identification circuit (A1). In the identification processing step, the branch circuit (B1) in which leakage current occurred is identified among the plurality of branch circuits (B1) based on the leakage current detection information and the plurality of load current information relating to the plurality of branch circuits (B1). The identification circuit (A1) is a branch circuit (B1) in which both poles are ungrounded.

[0127] According to the above embodiment, it is possible to provide a leakage current identification method that makes it easier to identify leakage current locations at the branch circuit (B1) level while keeping the number of zero-phase current transformers low.

[0128] The program according to the tenth embodiment is a program that causes one or more processors to execute the leakage current identification method according to the ninth embodiment.

[0129] According to the above embodiment, it is possible to reduce the number of zero-phase current transformers (2) while providing a function that makes it easier to identify leakage points at the branch circuit (B1) level.

[0130] The configurations relating to aspects 2 to 7 are not essential to the leakage current identification system (1) and may be omitted as appropriate. [Explanation of symbols]

[0131] 100-unit distribution board 101 Panel 1. Leakage current detection system 11 First acquisition part 12 Second acquisition part 13 Third acquisition part 14 Specific section 15 Notification Department 2 Zero phase current transformer 3. Branch current detection unit 4. Main Current Detection Unit A1 Specific circuit B1 Branch Circuit M1 main circuit

Claims

1. A first acquisition unit acquires leakage current detection information based on the detection result of zero-sequence current detected by a zero-sequence current transformer installed in the main circuit, A second acquisition unit acquires load current information based on the load current detection results detected by one or more branch current detection units provided in each of a plurality of branch circuits including at least one specific circuit, Based on the leakage detection information and the load current information relating to the plurality of branch circuits, an identification unit identifies the branch circuit in which leakage occurred among the plurality of branch circuits, Equipped with, The aforementioned specific circuit is a branch circuit in which both poles are ungrounded. Leakage current detection system.

2. The specified part is, The timing of the leakage current occurrence is identified from the aforementioned leakage current detection information. In the load current information for the plurality of branch circuits, it is determined whether or not there is a sudden branch current fluctuation occurring at the same timing as the occurrence timing. If there is a sudden fluctuation in branch current, the branch circuit whose load current information indicates the sudden fluctuation in branch current is determined to be the branch circuit where a ground fault occurred. The leakage current detection system according to claim 1.

3. The aforementioned specific circuit is provided with the branch current detection unit for only one of the two poles. The identifying unit determines that the identified circuit is a branch circuit where a ground fault occurred if there is no sudden branch current fluctuation in any of the load current information. The leakage current detection system according to claim 2.

4. The main circuit further comprises a third acquisition unit that acquires main current information based on the detection results of the main current detected by one or more main current detection units provided in the main circuit, The aforementioned specific circuit is provided with the branch current detection unit for only one of the two poles. The specified part is, In the aforementioned main current information, it is determined whether or not there is a sudden main current fluctuation occurring at the same timing as the occurrence timing. If there is no sudden branch current fluctuation in the multiple load current information, and there is a sudden main current fluctuation in the main current information, then the specific circuit is determined to be a branch circuit where a ground fault occurred. The leakage current detection system according to claim 2.

5. The specified circuit is provided with the branch current detection unit for each of the two poles. The leakage current detection system according to claim 2.

6. The identification unit compares the frequency components of the current with the leakage detection information and the load current information of the plurality of branch circuits to identify the branch circuit in which leakage occurred among the plurality of branch circuits. A leakage current detection system according to any one of claims 1 to 5.

7. The system further includes a notification unit that notifies the results of the identification performed by the identification unit. The leakage current detection system according to claim 1.

8. The leakage current detection system according to claim 1, The zero-phase current transformer and, Multiple branch current detection units, The panel body housing the leakage current detection system, the zero-phase current transformer, and the plurality of branch current detection units, Equipped with, Distribution board.

9. A first acquisition process step involves acquiring leakage detection information based on the detection result of zero-sequence current detected by a zero-sequence current transformer installed in the main circuit, A second acquisition process step of acquiring load current information based on the detection results of load currents detected by one or more branch current detection units provided in each of a plurality of branch circuits including at least one specific circuit, A specific processing step to identify the branch circuit in which a leakage current occurred among the multiple branch circuits based on the leakage current detection information and the multiple load current information relating to the multiple branch circuits, Equipped with, The aforementioned specific circuit is a branch circuit in which both poles are ungrounded. Electric leakage identification method.

10. A program for causing one or more processors to execute the leakage current identification method described in claim 9.

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