Measurement device, measurement method, and measurement program

Abstract

The measurement device includes a measurement unit (2) and a selection processing unit (51). The measuring unit (2) comprises: a first measuring unit (11) that measures, by means of a first configuration, a circuit electrical correlation value of an electrical line branched from an electrical line to be measured to which a star-connected three-phase AC power supply is connected; a second measurement unit (21) that measures, by means of a second configuration, a circuit electrical correlation value of an electrical line branched from an electrical line to be measured to which a star-connected three-phase AC power supply is connected; third measurement unit (31) for measuring, by means of a third configuration, a circuit electrical correlation value of an electrical line branching from an electrical line to be measured to which a delta-connected three-phase AC power supply is connected, and first measurement unit (31) for measuring, by means of a fourth configuration, a circuit electrical correlation value of an electrical line branching from an electrical line to be measured to which a delta-connected three-phase AC power supply is connected Any two or more of the four measuring units (41) are configured. The selection processing unit (51) selects any one of the measurement units (2).

Description

Technical Field

[0001] This disclosure relates to a measuring device, measuring method, and measuring procedure for measuring electrically related values ​​of a circuit. Background Technology

[0002] There are two main methods for supplying electricity to households, factories, and other facilities: three-phase AC (hereinafter referred to as three-phase) and single-phase AC (hereinafter referred to as single-phase). Single-phase AC is commonly used in ordinary households where high voltage is not required due to the smaller number of wires and lower voltage. Compared to single-phase AC, three-phase AC can achieve the same power with less current, resulting in less energy loss, and is often used in factories and other facilities with high power consumption.

[0003] Furthermore, in factories and other facilities utilizing three-phase AC power, it is necessary to branch the three-phase power supply into single-phase power when using devices driven by single-phase electricity. Patent Document 1 discloses a technique for converting three-phase AC power output from a three-phase three-wire AC power supply into single-phase AC power using a three-phase to single-phase transformer. Additionally, measuring electrical-related values ​​of the circuit (hereinafter referred to as circuit electrical-related values) and confirming whether these values ​​fall within the normal range is crucial for ensuring safety at all times.

[0004] Existing technical documents Patent documents Patent document 1: Japanese Patent Publication No. 2021-162234. Summary of the Invention

[0005] -The technical problem the invention aims to solve- Here, when the three-phase circuit is branched into single-phase circuits as described above, it is also desirable to accurately measure the electrical related values ​​of the circuit.

[0006] The purpose of this disclosure is to provide a measuring device, measuring method, and measuring procedure that can accurately measure the electrical values ​​of a single-phase circuit when a three-phase circuit is branched into a single-phase circuit and a load is arranged in the single-phase circuit.

[0007] - Technical solutions used to solve technical problems - To achieve the above objectives, the structure of this disclosure is as follows.

[0008] (1) A measuring device comprising a measuring unit and a selection processing unit, wherein the measuring unit is composed of any two or more of a first measuring unit, a second measuring unit, a third measuring unit, and a fourth measuring unit; the first measuring unit utilizes a first structure measuring circuit electrical correlation value, the electrical correlation value of which is electrically related to a branch line from a three-phase AC power supply connected in a star configuration, which branches off from the three-phase AC power supply into a single-phase AC power supply and distributes the power; the second measuring unit utilizes a second structure measuring circuit electrical correlation value, the electrical correlation value of which is electrically related to a branch line from a three-phase AC power supply connected in a star configuration. The third measuring unit measures the electrical correlation values ​​of the tested circuits branching off from the three-phase AC power supply connected in a delta configuration, and the electrical correlation values ​​of the ... The selection processing unit selects any one of the measurement units.

[0009] (2) According to the measuring device described in (1), In the following first state, the selection processing unit selects the first measurement unit. In this first state, the three-phase AC power supply with the first phase, second phase, third phase, and neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first phase, second phase, or third phase and the neutral line. In the following second state, the selection processing unit selects the second measurement unit. In this second state, the three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the following third state, the selection processing unit selects the third measurement unit. In this third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test. The load is connected to the grounded phase and any one of the ungrounded phases. In the following fourth state, the selection processing unit selects the fourth measurement unit. In the fourth state, a three-phase AC power supply with the first, second, and third phases delta-connected and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0010] (3) According to the measuring device described in (1) or (2), the first measuring unit, as the first structure, calculates the leakage current component caused by the insulation resistance to ground in the leakage current based on the leakage current flowing through the circuit under test and the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. The second measurement unit, as the second structure, calculates the leakage current component caused by the insulation resistance to ground within the leakage current, based on the leakage current flowing through the tested circuit and the voltage applied between the two phases connected to the load. The third measuring unit, as the third structure, calculates the leakage current component caused by the insulation resistance to ground within the leakage current based on the leakage current flowing through the tested circuit and the voltage applied between the phases connected to the load. The fourth measuring unit, as the fourth structure, calculates the leakage current component caused by the insulation resistance to ground in the leakage current based on the leakage current flowing through the circuit under test and the voltage applied between the phases connected to the load.

[0011] (4) A measuring device comprising a measuring unit and a selection processing unit, wherein the measuring unit measures electrical correlation values ​​of a circuit, the electrical correlation values ​​being electrical correlation values ​​with electrical correlation values ​​of a circuit branching off from a three-phase AC power supply connected in a star or delta configuration, or a circuit branching off from a three-phase AC power supply into a single-phase AC power supply for power distribution. The selection processing unit selects one state from any two or more of the following states: a first state, a second state, a third state, and a fourth state. In the first state, a three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first, second, or third phases and the neutral line. In the second state, a three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases. In the fourth state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases. When the selection processing unit selects either the first state or the third state, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. This value is the leakage current component caused by the insulation resistance to ground included in the leakage current. When the second state is selected by the selection processing unit, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between the two phases connected to the load, namely, the leakage current component caused by the insulation resistance to ground included in the leakage current. When the fourth state is selected by the selection processing unit, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between the phases connected to the load, namely the leakage current component caused by the insulation resistance to ground included in the leakage current.

[0012] (5) A measurement method comprising a selection processing step and a measurement step, wherein in the selection processing step, any one of a plurality of measurement units that measures electrical correlation values ​​of a circuit using different structures is selected, wherein the electrical correlation value of the circuit is an electrical correlation value with a circuit branching off from a three-phase AC power supply connected in a star or delta configuration, or a circuit branching off from a three-phase AC power supply into a single-phase AC power supply for power distribution. In the measurement step, the measurement is performed using the measurement unit selected by the selection processing step. The measuring unit is composed of any two or more of the following: a first measuring unit, a second measuring unit, a third measuring unit, and a fourth measuring unit. The first measuring unit uses a first-structure measuring circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a star configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The second measurement unit utilizes a second-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and between the three-phase AC branching off into single-phase AC circuits for power distribution. The third measurement unit utilizes a third-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a delta configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The fourth measurement unit uses the fourth structure to measure the electrical correlation value of the circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the tested circuit connected to a three-phase AC power supply with delta connection, and the circuit branching off from the three-phase AC power supply to a single-phase AC power supply for power distribution.

[0013] (6) A measurement program for causing a computer to perform a selection processing step and a measurement step, In the selection process step, one of several measuring units is selected from multiple measuring units that measure electrical correlation values ​​using different circuit structures. These electrical correlation values ​​are related to the electrical properties of the measured circuit branching off from a three-phase AC power supply connected in a star or delta configuration, or to a circuit branching off from a three-phase AC power supply into a single-phase AC power supply for distribution. In the measurement step, the measurement is performed using the measurement unit selected by the selection processing step. The measuring unit is composed of any two or more of the following: a first measuring unit, a second measuring unit, a third measuring unit, and a fourth measuring unit. The first measuring unit uses a first-structure measuring circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a star configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The second measurement unit utilizes a second-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and between the three-phase AC branching off into single-phase AC circuits for power distribution. The third measurement unit utilizes a third-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a delta configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The fourth measurement unit uses the fourth structure to measure the electrical correlation value of the circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the tested circuit connected to a three-phase AC power supply with delta connection, and the circuit branching off from the three-phase AC power supply to a single-phase AC power supply for power distribution.

[0014] -The effects of the invention- According to this disclosure, even when a three-phase circuit is branched into a single-phase circuit, it is possible to accurately measure electrical-related values ​​of the circuit. Attached Figure Description

[0015] Figure 1 This is a diagram showing a first structural example of a measuring device.

[0016] Figure 2 This is a diagram showing a second structural example of the measuring device.

[0017] Figure 3 This is a diagram showing a third structural example of the measuring device.

[0018] Figure 4 This diagram illustrates the structure in which the selection processing unit automatically identifies the state (first state to fourth state) of the load.

[0019] Figure 5 This is a block diagram showing the structure of the first measuring unit.

[0020] Figure 6 This is a block diagram showing a modified example of the first measuring unit.

[0021] Figure 7 This is a block diagram showing the structure of the second measuring unit.

[0022] Figure 8 This is a block diagram showing a modified example of the second measuring unit.

[0023] Figure 9 This is a schematic diagram illustrating the situation where the Ior and Ioc of each phase are represented by vectors in a star connection.

[0024] Figure 10 This is a block diagram showing the structure of the third measuring unit.

[0025] Figure 11 This is a block diagram showing a modified example of the third measuring unit.

[0026] Figure 12 This is a block diagram showing the structure of the fourth measuring unit.

[0027] Figure 13 This is a block diagram showing a modified example of the fourth measuring unit.

[0028] Figure 14 This is a schematic diagram illustrating the situation where Ior and Ioc of each phase are represented by vectors in a triangular connection.

[0029] Figure 15 This is a diagram showing other structures of the measuring device.

[0030] Figure 16 This is a flowchart illustrating the steps of the measurement method.

[0031] Figure 17 This is a flowchart illustrating the other steps of the measurement method.

[0032] Figure 18 This is a block diagram illustrating a first example of a computer architecture.

[0033] Figure 19 This is a block diagram illustrating a second example of a computer architecture. Detailed Implementation

[0034] The following describes this embodiment. It should be noted that the embodiment described below is not intended to unduly limit the scope of the disclosure as stated in the claims. Furthermore, not all structures described in this embodiment are necessarily essential components of this disclosure. Additionally, the method of branching a single-phase circuit from a three-phase AC connection to supply power to a load is also a common practice among home electrical appliance users in Japan. Moreover, in countries outside Japan, this method is almost universally used to supply power to loads, and the technology proposed in this proposal can be applied in countries outside of Japan as well.

[0035] Figure 1 This diagram illustrates a first structural example of the measuring device 1. The measuring device 1 includes a measuring unit 2 and a selection processing unit 51. The measuring unit 2 includes a first measuring unit 11, a second measuring unit 21, a third measuring unit 31, and a fourth measuring unit 41. It should be noted that, in this embodiment, the measuring device 1 uses... Figure 1 The first structural example shown is used for explanation, but the invention is not limited to this structural example. The measuring unit 2 is composed of any two or more of the following: the first measuring unit 11, the second measuring unit 21, the third measuring unit 31, and the fourth measuring unit 41. For example, as... Figure 2 As shown, the measuring device 1a can also be composed of a measuring unit 2a that includes only the first measuring unit 11 and the second measuring unit 21 (second structural example). Furthermore, as... Figure 3 As shown, the measuring device 1b can also be composed of a measuring unit 2b that includes only the third measuring unit 31 and the fourth measuring unit 41 (third structure example).

[0036] The first measurement unit 11 utilizes a first-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to electrical circuits branching off from the tested circuit connected to a star-connected three-phase AC power supply, or branching off from the three-phase AC power supply into single-phase AC power for distribution. Details of the structure of the first measurement unit 11 (the first structure) will be described later. The first measurement unit 11 calculates the phase angle θ based on the leakage current Io flowing through the tested circuit and the voltage applied between any one of the first, second, or third phases with a load and the neutral line. Ior = Io × cosθ (1) One of the electrical-related values ​​of the circuit is calculated, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io.

[0037] The second measurement unit 21 utilizes a second-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical correlation values ​​of the circuit branching off from the tested circuit connected to a star-connected three-phase AC power supply, and to the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. Details of the structure of the second measurement unit 21 (the second structure) will be described later. The second measurement unit 21 measures electrical correlation values ​​based on the leakage current Io flowing through the tested circuit and the phase angle θ calculated from the voltage applied between the two phases connected to the load. Ior=Io×sinθ / cos60° (2) One of the electrical-related values ​​of the circuit is calculated, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io.

[0038] The third measurement unit 31 utilizes a third-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical correlation values ​​of the circuit branching off from the tested circuit connected to a three-phase AC power supply via a delta connection, and to the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. Details of the structure of the third measurement unit 31 (the third structure) will be described later. The third measurement unit 31 measures values ​​based on the leakage current Io flowing through the tested circuit and the phase angle θ calculated from the voltage applied between the phases connected to the load. Ior = Io × cosθ (3) One of the electrical-related values ​​of the circuit is calculated, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io.

[0039] The fourth measurement unit 41 utilizes a fourth structure to measure electrical correlation values ​​of a circuit. These electrical correlation values ​​are related to the electrical correlation values ​​of a circuit branching off from a three-phase AC power supply connected in a delta configuration, and then branching off into single-phase AC circuits for power distribution. Details of the structure of the fourth measurement unit 41 (the fourth structure) will be described later. The fourth measurement unit 41 measures values ​​based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load. Ior=Io×sinθ / cos30° (4) One of the electrical-related values ​​of the circuit is calculated, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io.

[0040] The selection processing unit 51 selects any one of the first measurement unit 11, the second measurement unit 21, the third measurement unit 31, and the fourth measurement unit 41.

[0041] Here, the operation of the selection processing unit 51 will be explained. In the following first state, the selection processing unit 51 selects the first measurement unit 11. In this first state, the three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load (a load used in a single phase) is connected to any one of the first, second, or third phases and the neutral line. Here, a lighting circuit or a device connected to a single-phase socket is equivalent to a load.

[0042] In the following second state, the selection processing unit 51 selects the second measurement unit 21. In the second state, the three-phase AC power supply with the first, second and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second and third phases.

[0043] In the following third state, the selection processing unit 51 selects the third measurement unit 31. In the third state, the three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases.

[0044] In the following fourth state, the selection processing unit 51 selects the fourth measurement unit 41. In the fourth state, the three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0045] The selection processing unit 51 may be configured as, for example, a rotary switch. When the switch is operated by the operator, the selection processing unit 51 selects the measuring unit specified by the switch. The measuring unit selected by the selection processing unit 51 then operates.

[0046] Alternatively, the selection processing unit 51 can automatically identify the state of the load (from the first state to the fourth state) and select the structure of the measurement unit based on the identification result. The example given is a secondary-side test cable consisting of four wires, but it is also applicable to a three-wire configuration. Figure 4 This diagram illustrates the structure in which the selection processing unit 51 automatically identifies the state (first state to fourth state) of the load connection.

[0047] The selection processing unit 51 includes a switching unit 52, a voltage detection unit 53, a leakage current detection unit 54, and a control unit 55. It should be noted that the voltage detection unit 53 can also be implemented using any one or more of the voltage detection units 13, 23, 33, and 43 described later. Similarly, the leakage current detection unit 54 can also be implemented using any one or more of the leakage current detection units 12, 22, 32, and 42 described later.

[0048] All four wires (a, b, c, and d) of the circuit under test are connected to the switching unit 52. Based on the switching command from the control unit 55, the switching unit 52 selects any two wires from the connected circuit under test for connection. The switching unit 52 and the voltage detection unit 53 are connected by two wires. The voltage detection unit 53 detects the voltage applied to the circuit after switching by the switching unit 52.

[0049] Additionally, zero-sequence current transformers 61a to 61f are connected to the lines leading from the circuit being tested (in... Figure 4 In the example shown, there are six locations. Zero-sequence current transformers 61a to 61f are respectively connected to the leakage current detection unit 54.

[0050] Here, the operation of the control unit 55 will be explained. When switching unit 52 selects line a and line b, the control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by voltage detection unit 53, which is applied between line a and line b, and the leakage current detected by zero-sequence current transformer 61a, which is installed on the lines leading from line a and line b. Next, when switching unit 52 selects line a and line c, the control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by voltage detection unit 53, which is applied between line a and line c, and the leakage current detected by zero-sequence current transformer 61b, which is installed on the lines leading from line a and line c. Secondly, when switching unit 52 selects line a and line d, control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by voltage detection unit 53 applied between line a and line d, and the leakage current detected by zero-sequence current transformer 61c clamped on the lines leading from line a and line d. Secondly, when switching unit 52 selects line b and line c, control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by voltage detection unit 53 applied between line b and line c, and the leakage current detected by zero-sequence current transformer 61d clamped on the lines leading from line b and line c. Secondly, when the switching unit 52 selects line b and line d, the control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by the voltage detection unit 53, which is applied between line b and line d, and the leakage current detected by the zero-sequence current transformer 61e clamped on the lines leading from line b and line d. Secondly, when the switching unit 55 selects line c and line d, the control unit 55 stores the following voltage and leakage current corresponding to each other: the voltage detected by the voltage detection unit 53, which is applied between line c and line d, and the leakage current detected by the zero-sequence current transformer 61f clamped on the lines leading from line c and line d.

[0051] The control unit 55 determines whether the connection is star (first state or second state) or delta (third state or fourth state) based on the stored voltages. For example, if the voltages between phase R and neutral line N (or ground E), phase S and neutral line N (or ground E), and phase T and neutral line N (or ground E) are approximately equal, the control unit 55 determines it to be a star connection. Conversely, if there is a difference between the voltages between phase R and ground E and phase S and ground E, or if there is a difference between the voltages between phase T and ground E and phase S and ground E, the control unit 55 determines it to be a delta connection.

[0052] When the control unit 55 determines that the connection is star-connected, if the load is connected to any phase and the neutral line N, the control unit 55 identifies it as a first state; if the load is not connected to any phase and the neutral line N, the control unit 55 identifies it as a second state. Alternatively, a structure can be adopted in which a first switch is provided in the measuring device 1, indicating whether the load is connected to any phase and the neutral line N. The user confirms the wiring status and turns the first switch on or off. If the first switch is on, the control unit 55 determines that the load is connected to any phase and the neutral line N; if the first switch is off, the control unit 55 determines that the load is not connected to any phase and the neutral line N. Furthermore, when the control unit 55 determines that the connection is delta-connected, if the range of the zero-sequence current transformer includes phase S, the control unit 55 identifies it as a third state; if the range of the zero-sequence current transformer does not include phase S, the control unit 55 identifies it as a fourth state. Alternatively, a structure can be adopted in which a second switch is provided in the measuring device 1. This second switch indicates whether the clamping range of the zero-sequence current transformer includes phase S. The user confirms the clamping state of the zero-sequence current transformer by turning the second switch on or off. If the second switch is on, the control unit 55 determines that the clamping range of the zero-sequence current transformer includes phase S; if the second switch is off, the control unit 55 determines that the clamping range of the zero-sequence current transformer does not include phase S.

[0053] The direction of leakage current refers to the angle when the leakage current is represented by a vector. Here, in the case of single-phase AC, the leakage current component Ioc caused by the electrostatic capacitance to ground and the leakage current component Ior caused by the insulation resistance to ground, which is directly related to the insulation resistance, are 90 degrees out of phase. Because the leakage current Io detected by the zero-sequence current transformer is the current synthesized from Ioc and Ior, this leakage current Io will appear somewhere within this 90-degree range.

[0054] In the following discussion Figure 9 The text also explains that, for example, in a star configuration, if the Ior of phase U is at 30 degrees, the Ior of phase V is at 150 degrees, and the Ior of phase W is at 270 degrees. Furthermore, since the Ioc of phase U is at 120 degrees, the Io of phase U falls within the range of 30 to 120 degrees. Similarly, since the Ioc of phase V is at 240 degrees, the Io of phase U falls within the range of 150 to 240 degrees. And since the Ioc of phase W is at 360 (0) degrees, the Io of phase U falls within the range of 270 to 360 (0) degrees.

[0055] The control unit 55 determines which wires are being clamped based on the direction of the leakage current Io detected by the zero-sequence current transformer.

[0056] It should be noted that the selection processing unit 51 can also be configured to select only two arbitrary wires (e.g., wire a and wire b) from the wires constituting the circuit under test and connect them to the voltage detection unit 53. In this configuration, the selection processing unit 51 does not have a switching unit 52, and the selection processing unit 51 performs a calculation (e.g., 120°) to shift the phase of the leakage current detected by the zero-sequence current transformer that holds the wires other than the two connected wires, in order to identify the state of the load (first state to fourth state).

[0057] For example, the measuring device 1 includes a first selection unit, a second selection unit, and a third selection unit. The first selection unit selects whether the power supply side is connected in a star or delta configuration; the second selection unit selects which of the two wires (phases) connected to the voltage detection unit 53 is which; and the third selection unit selects which of the two phases clamped by the zero-sequence current transformer is which. Based on the states selected by the first, second, and third selection units, the selection processing unit 51 identifies the state with a load and calculates Ior.

[0058] Specifically, when the first selection unit selects a star connection, the second selection unit selects the R-phase and T-phase to be connected to the voltage detection unit 53, and the third selection unit selects the R-phase and T-phase to be clamped by the zero-sequence current transformer, the state with load is identified as the second state, and Ior is calculated using the following formula.

[0059] Ior = Io × sinθ / cos60° Furthermore, when the first selection unit selects a star connection, the second selection unit selects the R phase and T phase to be connected to the voltage detection unit 53, and the third selection unit selects the S phase and T phase to be clamped by the zero-sequence current transformer, the state with load is identified as the second state. However, since the phase connected to the voltage detection unit 53 is different from the phase clamped by the zero-sequence current transformer, the phase of the leakage current detected by the zero-sequence current transformer is shifted by 120°, and Ior is calculated using the following formula.

[0060] Ior = Io × sin(θ - 120°) / cos60° Furthermore, when the first selection unit selects a delta connection, the second selection unit selects the R phase and T phase to be connected to the voltage detection unit 53, and the third selection unit selects the S phase and T phase to be clamped by the zero-sequence current transformer, the state with load is identified as the third state. However, since the phase connected to the voltage detection unit 53 is different from the phase clamped by the zero-sequence current transformer, the phase of the leakage current detected by the zero-sequence current transformer is shifted by 120°, and Ior is calculated using the following formula.

[0061] Ior = Io × cos(θ - 120°) It should be noted that the first selection unit may also include a structure that selects whether the power supply side is single-phase.

[0062] As described above, the selection processing unit 51 measures all phase-to-phase voltages and voltages to ground, identifies the circuit based on the phase and voltage to ground, automatically identifies the state with load (first state to fourth state) based on the clamping phase of the zero-sequence current transformer (ZCT), and selects the measurement unit based on the identification result.

[0063] After doing so, when converting the three-phase AC output from the three-phase AC power supply to single-phase AC and connecting a load to the single-phase AC power supply line, the measuring device 1 can select the measuring unit (the first measuring unit 11 to the fourth measuring unit 41) that is suitable for the state of the three-phase AC power supply (the first state to the fourth state mentioned above), and can accurately calculate the circuit electrical related values ​​generated on the power supply line (in particular, the leakage current component Ior caused by the insulation resistance to ground included in the leakage current).

[0064] <Regarding the structure and operation of the first measurement unit 11> Here, the specific structure and operation of the first measuring unit 11 will be described. The first measuring unit 11 operates in the following first state. In the first state, the three-phase AC power supply with the first phase, second phase, third phase and neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first phase, second phase or third phase and the neutral line.

[0065] Figure 5 This is a block diagram showing the structure of the first measurement unit 11. Specifically, it is a block diagram showing the structure of the first measurement unit 11 and a diagram showing the connection state of the first measurement unit 11 and the circuit under test when the control unit 55 identifies it as a first state and the selection processing unit 51 selects the first measurement unit 11. The first measurement unit 11 includes a leakage current detection unit 12, a voltage detection unit 13, a phase angle calculation unit 14, and a leakage current component calculation unit for insulation resistance to ground (hereinafter referred to as the leakage current component calculation unit) 15.

[0066] The leakage current detection unit 12 detects the leakage current flowing through the tested circuit connected to a load. The leakage current detection unit 12 detects the leakage current flowing through the first phase, second phase, and third phase branching off from the star (Y) connection of the single-phase circuit. Hereinafter, the first phase will be referred to as phase U, the second phase as phase V, and the third phase as phase W, but this designation is not limited. Furthermore, the leakage current measured by the leakage current detection unit 12 will be referred to as "Io" below, but this designation is not limited.

[0067] A zero-sequence current transformer (ZCT) 10 is connected to the leakage current detection unit 12. The zero-sequence current transformer 10 adopts a structure that uniformly clamps the circuit. For example, the zero-sequence current transformer 10 is composed of a portable, through-type split-type zero-sequence current transformer, which allows field personnel to easily install the zero-sequence current transformer 10 on the circuit. The leakage current detection unit 12 detects (calculates) the leakage current Io flowing through the circuit under test based on the signal measured by the zero-sequence current transformer 10.

[0068] The voltage detection unit 13 detects the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. Figure 5 The diagram shows an example where the load is arranged between phase U and neutral line N. Additionally, the voltage detection unit 13 detects the voltage applied between phase U and neutral line N. It should be noted that the load can also be arranged between phase V and neutral line N, or between phase W and neutral line N. When the load is arranged between phase V and neutral line N, the voltage detection unit 13 detects the voltage applied between phase V and neutral line N. When the load is arranged between phase W and neutral line N, the voltage detection unit 13 detects the voltage applied between phase W and neutral line N.

[0069] The phase angle calculation unit 14 calculates the phase angle based on the leakage current detected by the leakage current detection unit 12 and the voltage detected by the voltage detection unit 13. Specifically, the phase angle calculation unit 14 calculates the phase angle based on the waveform of the leakage current Io detected by the leakage current detection unit 12 and the voltage (e.g., reference voltage V) detected by the voltage detection unit 13. N-U The waveform of the signal is processed to detect the phase angle θ. For example, the phase angle calculation unit 14 is based on the reference voltage V. N-U The zero-crossing point of the leakage current Io and the zero-crossing point of the reference voltage V are detected. N-U The phase angle θ between the leakage current Io and the current. Alternatively, the phase angle calculation can be performed using synchronous detection and DFT (Discrete Fourier Transform). The structure using synchronous detection will be described later.

[0070] The leakage current component calculation unit 15 uses the above formula (1) to calculate the leakage current component Ior caused by the ground insulation resistance in the leakage current, based on the leakage current Io detected by the leakage current detection unit 12 and the phase angle θ calculated by the phase angle calculation unit 14. Hereinafter, the leakage current component caused by the ground insulation resistance will sometimes be referred to as "Ior".

[0071] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0072] After doing so, the measuring device 1, including the first measuring unit 11, can accurately calculate the Ior generated in the single-phase circuit branching from the star connection based on the leakage current Io detected by the leakage current detection unit 12 and the phase angle (phase difference) calculated by the phase angle calculation unit 14. That is to say, the first measuring unit 11 is a measuring unit used in the case where a load is arranged between the neutral line N and phase U, neutral line N and phase V, or neutral line N and phase W in the star connection and it is used as a single-phase circuit.

[0073] Here, the potential difference between E (ground) and neutral line N (between N phase and ground) is essentially 0 [V], and the voltage between EU phases, EV phases, or EW phases (between each phase and ground) is a specified voltage (e.g., 100 [V]). The load is arranged between neutral line N and U phases, neutral line N and V phases, or neutral line N and W phases connected as a single-phase circuit. The first measuring unit 11 detects the voltage V between the phases where the load is arranged, calculates the phase difference θ between the waveform of this voltage (sine wave) and the waveform of the leakage current Io input from the zero-sequence current transformer (ZCT) 10, and substitutes the leakage current Io and the phase difference θ into equation (1) to calculate Ior.

[0074] In addition to measuring and calculating the aforementioned leakage currents Io and Ior, the measuring device 1 can also measure and calculate various values ​​such as current value, power value, the history of these values ​​changing over time, and fluctuations over time as electrical-related values ​​of the circuit. Furthermore, the measuring device 1 can also use these electrical-related values ​​of the circuit to inspect or monitor the electrical circuit under test.

[0075] Furthermore, the structure of the first measuring unit 11 is an example, and is not limited to the structure described above. For example... Figure 6 As shown, the first measurement unit 11 may also adopt a structure including an arithmetic unit 16 instead of the phase angle detection unit 14 and the leakage current component calculation unit 15.

[0076] The calculation unit 16 performs an integral operation based on synchronous detection based on the leakage current (waveform) detected by the leakage current detection unit 12 and the voltage (waveform) detected by the voltage detection unit 13 to calculate the leakage current component Ior (Io×cosθ) caused by the insulation resistance to ground. The integral operation based on synchronous detection is to calculate Io×cosθ by integrating the waveform within a specified range such as 0 to 180 degrees. A specific example is shown below. It should be noted that the integral operation based on synchronous detection is not limited to the following cases.

[0077] The arithmetic unit 16 performs prescribed processing on the voltage value (voltage waveform) detected by the voltage detection unit 13 and the leakage current (current waveform) detected by the leakage current detection unit 12, outputting parameter signals of the logic signals. It also performs full-wave rectification on the leakage current (current waveform) detected by the leakage current detection unit 12, quantizes the rectified current waveform using a continuous-mode ΔΣ ADC (continuous-mode ΔΣ analog-to-digital converter), measures the parameters of the sin and cos logic signals generated by the quantization transformation, and calculates the average value of the current waveform obtained by continuous-mode ΔΣ ADC processing. Specifically, the arithmetic unit 16 performs logic processing on the voltage value (voltage waveform) detected by the voltage detection unit 13 to generate a first logic signal, performs logic processing on the leakage current (current waveform) detected by the leakage current detection unit 12 to generate a second logic signal, performs arithmetic processing on the first and second logic signals, and outputs a positive / negative or high / low signal (first signal). Furthermore, the arithmetic unit 16 generates zero-crossing points when the first logic signal changes and stores the time between the generated zero-crossing points. During a period less than half the stored time between the next zero-crossing point, the first logic signal is inverted, a phase transition of the first logic signal is performed, and the voltage waveform after phase transition and the second logic signal are processed to output a positive or negative or high / low signal (second signal). The arithmetic unit 16 performs quantization-based counting using a continuous-type ΔΣADC based on the first and second signals, thereby obtaining the average value of the desired type of current value. The desired type of current value includes alternating current, and the input current I[A], active current Ir=Icosθ[A], and reactive current IL-IC=Isinθ[A] can be calculated. Here, the aforementioned "active current Ir=Icosθ" is the leakage current component Ior caused by the insulation resistance to ground.

[0078] Based on the above structure, the leakage current component Ior caused by the insulation resistance to ground can be calculated without performing vector calculations of the phase difference, which is an advantage.

[0079] <Regarding the structure and operation of the second measurement unit 21> Next, the specific structure and operation of the second measurement unit 21 will be explained. The second measurement unit 21 operates in the following second state, in which the three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases.

[0080] Figure 7This is a block diagram showing the structure of the second measurement unit 21. Specifically, it is a block diagram showing the structure of the second measurement unit 21 and a diagram showing the wiring state of the second measurement unit 21 and the circuit under test when the control unit 55 identifies it as the second state and the selection processing unit 51 selects the second measurement unit 21. The second measurement unit 21 includes a leakage current detection unit 22, a voltage detection unit 23, a phase angle calculation unit 24, and a leakage current component calculation unit for ground insulation resistance (hereinafter referred to as the leakage current component calculation unit) 25.

[0081] The leakage current detection unit 22 detects the leakage current flowing through the tested circuit connected to a load. The leakage current detection unit 22 detects the leakage current flowing through the first phase, second phase, and third phase branching off from the star (Y) connection of the single-phase circuit. Hereinafter, the first phase will be referred to as phase U, the second phase as phase V, and the third phase as phase W, but this designation is not limited. Furthermore, the leakage current measured by the leakage current detection unit 22 will be referred to as "Io" below, but this designation is not limited.

[0082] A zero-sequence current transformer (ZCT) 10 is connected to the leakage current detection unit 22. The zero-sequence current transformer 10 adopts a structure that uniformly clamps the circuit. For example, the zero-sequence current transformer 10 is composed of a portable, through-type split-type zero-sequence current transformer, which allows field personnel to easily install the zero-sequence current transformer 10 on the circuit. The leakage current detection unit 22 detects (calculates) the leakage current Io flowing through the circuit under test based on the signal measured by the zero-sequence current transformer 10.

[0083] The voltage detection unit 23 detects the voltage applied between the two phases connected to the load. Figure 7 The example shown is a load positioned between phases U and W. Additionally, voltage detection unit 23 detects the voltage applied between phases U and W. It should be noted that the load can also be positioned between phases V and U, or between phases V and W. When the load is positioned between phases V and U, voltage detection unit 23 detects the voltage applied between phases V and U. When the load is positioned between phases V and W, voltage detection unit 23 detects the voltage applied between phases V and W.

[0084] The phase angle calculation unit 24 calculates the phase angle based on the leakage current detected by the leakage current detection unit 22 and the voltage detected by the voltage detection unit 23. Specifically, the phase angle calculation unit 24 calculates the phase angle based on the waveform of the leakage current Io detected by the leakage current detection unit 22 and the voltage (e.g., reference voltage V) detected by the voltage detection unit 23. U－W The waveform of the signal is processed to detect the phase angle θ. For example, the phase angle calculation unit 24 is based on the reference voltage V. U-W The zero-crossing point of the leakage current Io and the zero-crossing point of the reference voltage V are detected. U-WThe phase angle θ between the leakage current Io and the current. Alternatively, the phase angle calculation can be performed using synchronous detection and DFT (Discrete Fourier Transform). The structure using synchronous detection will be described later.

[0085] The leakage current component calculation unit 25 uses the above formula (2) to calculate the leakage current component Ior caused by the insulation resistance to ground in the leakage current, based on the leakage current Io detected by the leakage current detection unit 22 and the phase angle θ calculated by the phase angle calculation unit 24.

[0086] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0087] After doing so, the measuring device 1, including the second measuring unit 21, can accurately calculate the Ior generated in the single-phase circuit branching from the star connection based on the leakage current Io detected by the leakage current detection unit 22 and the phase angle (phase difference) calculated by the phase angle calculation unit 24. In other words, the second measuring unit 21 is a measuring unit used in the case where a load is arranged between the U phase and V phase, V phase and W phase, or U phase and W phase in the star connection and it is used as a single-phase circuit.

[0088] For example, in a single-phase circuit where the load is connected between phases U and V, the voltage between phase E (ground) and phase U and phase EV is the same (e.g., 100V), while the voltage between phase U and phase V is different (e.g., 200V). The load is arranged between phases U and V, phase V and phase W, or phase U and phase W. The second measurement unit 21 detects the voltage V between the phases where the load is arranged, calculates the phase difference θ between the waveform of this voltage (sine wave) and the waveform of the leakage current Io input from the zero-sequence current transformer (ZCT) 10, and substitutes the leakage current Io and the phase difference θ into equation (2) to calculate Ior.

[0089] Here, the potential difference between phase U and phase V and ground is the same under normal circumstances. In this case, even if floating capacitance is generated in phase U and phase V, the amount of floating capacitance generated in both is the same, and the floating capacitance will not become unbalanced.

[0090] Here, the reasons why it will not become unbalanced are explained. The leakage current Io includes the leakage current component caused by the electrostatic capacitance to ground (hereinafter referred to as "Ioc") and the leakage current component caused by the insulation resistance to ground, which is directly related to the insulation resistance (hereinafter referred to as "Ior").

[0091] In addition, using Figure 9 Explain the vector representation of Ioc and Ior. Figure 9It is a diagram that schematically illustrates the situation when Ioc and Ior of each phase are represented by vectors.

[0092] When the reference voltage is set to 0 degrees and the resistive leakage current flowing through phase U (hereinafter, sometimes referred to as "Ior(u)") is represented by a vector, if this resistive leakage current appears at position 30 degrees, the resistive leakage current flowing through phase V (hereinafter, sometimes referred to as "Ior(v)") appears at position 150 degrees, and the resistive leakage current flowing through phase W (hereinafter, sometimes referred to as "Ior(w)") appears at position 270 degrees. It should be noted that, hereinafter, vector Ior(u) will be simply referred to as Ior(u), vector Ior(v) as Ior(v), and vector Ior(w) as Ior(w). In this embodiment, the potentials of phases U and V are used as the reference voltage, and this voltage is set to 0 degrees.

[0093] Additionally, the capacitive leakage current flowing through phase U (hereinafter referred to as "Ioc(u)") occurs 90 degrees (π / 2) ahead of Ior(u), i.e., at a position of 120 degrees. The capacitive leakage current flowing through phase V (hereinafter referred to as "Ioc(v)") occurs 90 degrees (π / 2) ahead of Ior(v), i.e., at a position of 240 degrees. The capacitive leakage current flowing through phase W (hereinafter sometimes referred to as "Ioc(s)") occurs 90 degrees (π / 2) ahead of Ior(w), i.e., at a position of 0 degrees (360 degrees).

[0094] It should be noted that, in the following, vector Ioc(u) will be abbreviated as Ioc(u), vector Ioc(v) will be abbreviated as Ioc(v), and vector Ioc(w) will be abbreviated as Ioc(w).

[0095] The vector (Ioc(uv)) resulting from the synthesis of Ioc(u) and Ioc(v) appears at the 180-degree position. That is to say, the Ioc(u) generated in the U phase and the Ioc(v) generated in the V phase will not be out of balance.

[0096] It should be noted that when Ioc(u), Ioc(v), and Ioc(w) are in balance, Ioc(uv) and Ioc(w) are synthesized and cancel each other out, and no more Ioc is produced.

[0097] In addition to measuring and calculating the aforementioned leakage currents Io and Ior, the measuring device 1 can also measure and calculate various values ​​such as current value, power value, the history of these values ​​changing over time, and fluctuations over time as electrical-related values ​​of the circuit. Furthermore, the measuring device 1 can also use these electrical-related values ​​of the circuit to inspect or monitor the electrical circuit under test.

[0098] Furthermore, the structure of the second measuring unit 21 is an example, and is not limited to the structure described above. For example... Figure 8 As shown, the second measurement unit 21 may also include an arithmetic unit 26 to replace the phase angle detection unit 24 and the leakage current component calculation unit 25.

[0099] The calculation unit 26 performs an integral operation based on synchronous detection based on the leakage current (waveform) detected by the leakage current detection unit 22 and the voltage (waveform) detected by the voltage detection unit 23 to calculate the leakage current component Ior (Io×sinθ / cos60°) caused by the insulation resistance to ground. The integral operation based on synchronous detection is a calculation that calculates Io×sinθ and then divides it by cos60° by integrating the waveform within a specified range of 90 to 270 degrees. A specific example is shown below. It should be noted that the integral operation based on synchronous detection is not limited to the following cases.

[0100] The arithmetic unit 26 performs prescribed processing on the voltage value (voltage waveform) detected by the voltage detection unit 23 and the leakage current (current waveform) detected by the leakage current detection unit 22, outputting parameter signals of the logic signals. Furthermore, it performs full-wave rectification on the leakage current (current waveform) detected by the leakage current detection unit 22, quantizes the rectified current waveform using a continuous-mode ΔΣADC, measures the parameters of the sin and cos logic signals generated by the quantization transformation, and calculates the average value of the current waveform obtained through continuous-mode ΔΣADC processing. Specifically, the arithmetic unit 26 performs logic processing on the voltage value (voltage waveform) detected by the voltage detection unit 23 to generate a first logic signal, performs logic processing on the leakage current (current waveform) detected by the leakage current detection unit 22 to generate a second logic signal, performs arithmetic processing on the first and second logic signals, and outputs a positive / negative or high / low signal (first signal). Additionally, the arithmetic unit 26 generates zero-crossing points when the first logic signal changes and stores the time between the generated zero-crossing points. During a period less than half the stored time between the next zero-crossing point, the first logic signal is inverted, a phase shift of the first logic signal is performed, and the voltage waveform after phase shift and the second logic signal are processed to output a positive or negative or high / low signal (the second signal). Based on the first and second signals, the arithmetic unit 26 performs counting based on quantization transformation using a continuous ΔΣADC, thereby obtaining the average value of the desired type of current value. The desired type of current value includes AC current value, and the input current I[A], active current Ir=Icosθ[A], and reactive current IL-IC=Isinθ[A] can be calculated. The arithmetic unit 26 divides the "reactive current IL-IC=Isinθ" by cos60° to calculate the leakage current component Ior caused by the insulation resistance to ground.

[0101] Based on the above structure, the leakage current component Ior caused by the insulation resistance to ground can be calculated without calculating the phase angle, which is an advantage.

[0102] <Regarding the structure and operation of the third measurement unit 31> Next, the specific structure and operation of the third measuring unit 31 will be explained. The third measuring unit 31 operates in the following third state, in which a three-phase AC power supply with the first, second, and third phases delta-connected and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases.

[0103] Figure 10 This is a block diagram showing the structure of the third measurement unit 31. Specifically, it is a block diagram showing the structure of the third measurement unit 31 and a diagram showing the wiring state of the third measurement unit 31 and the circuit under test when the control unit 55 identifies it as the third state and the selection processing unit 51 selects the third measurement unit 31. The third measurement unit 31 includes a leakage current detection unit 32, a voltage detection unit 33, a phase angle calculation unit 34, and a leakage current component calculation unit for ground insulation resistance (hereinafter referred to as the leakage current component calculation unit) 35.

[0104] The leakage current detection unit 32 detects the leakage current flowing through the tested circuit connected to a load. The leakage current detection unit 32 detects the leakage current flowing through the first phase, second phase, and third phase branching off from the delta connection (Δ) in the single-phase circuit. Hereinafter, the first phase will be referred to as the R phase, the second phase as the S phase, and the third phase as the T phase, but this designation is not limited. Furthermore, the leakage current measured by the leakage current detection unit 32 will be referred to as "Io" below, but this designation is not limited. In this embodiment, the case where the S phase is grounded is described, but the R phase or T phase may also be grounded.

[0105] A zero-sequence current transformer (ZCT) 10 is connected to the leakage current detection unit 32. The zero-sequence current transformer 10 adopts a structure that uniformly clamps the circuit. For example, the zero-sequence current transformer 10 is composed of a portable, through-type split-type zero-sequence current transformer, which allows field personnel to easily install the zero-sequence current transformer 10 on the circuit. The leakage current detection unit 32 detects (calculates) the leakage current Io flowing through the circuit under test based on the signal measured by the zero-sequence current transformer 10.

[0106] The voltage detection unit 33 detects the voltage applied between the phases connected to the load. Figure 10 The example shown is a load arranged between phase R and phase S. Additionally, the voltage detection unit 33 detects the voltage applied between phase R and phase S. It should be noted that the load can also be arranged between phase T and phase S. When the load is arranged between phase T and phase S, the voltage detection unit 33 detects the voltage applied between phase T and phase S.

[0107] The phase angle calculation unit 34 calculates the phase angle based on the leakage current detected by the leakage current detection unit 32 and the voltage detected by the voltage detection unit 33. Specifically, the phase angle calculation unit 34 calculates the phase angle based on the waveform of the leakage current Io detected by the leakage current detection unit 32 and the voltage (e.g., reference voltage V) detected by the voltage detection unit 33. R-S The waveform of the signal is processed to detect the phase angle θ. For example, the phase angle calculation unit 34 is based on the reference voltage V. R-S The zero-crossing point of the leakage current Io and the zero-crossing point of the reference voltage V are detected. R-S The phase angle θ of the leakage current Io. Alternatively, the calculation of the phase angle can be performed using synchronous detection and DFT (Discrete Fourier Transform). The structure using synchronous detection will be described later.

[0108] The leakage current component calculation unit 35 uses the above formula (3) to calculate the leakage current component Ior caused by the insulation resistance to ground in the leakage current, based on the leakage current Io detected by the leakage current detection unit 32 and the phase angle θ calculated by the phase angle calculation unit 34.

[0109] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0110] After doing so, the measuring device 1, including the third measuring unit 31, can accurately calculate the Ior generated in the single-phase circuit branching from the delta connection based on the leakage current Io detected by the leakage current detection unit 32 and the phase angle (phase difference) calculated by the phase angle calculation unit 34. In other words, the third measuring unit 31 is a measuring unit used when a load is arranged between the R phase and the S phase (grounded phase) or the T phase and the S phase (grounded phase) in the delta connection and it is used as a single-phase circuit.

[0111] Here, the potential difference between phase E (ground) and phase S (grounded phase) (between phase S and ground) is essentially 0 [V], and the voltage between phases ER and ET (between each phase and ground) is a specified voltage (e.g., 200 [V]). The load is arranged between phases S and R or between phases S and T, which are connected as a single-phase circuit. The second measuring unit 21 detects the voltage V between the phases with the load, calculates the phase difference θ between the waveform of this voltage (sine wave) and the waveform of the leakage current Io input from the zero-sequence current transformer (ZCT) 10, substitutes the leakage current Io and the phase difference θ into equation (3), and calculates Ior accordingly.

[0112] In addition to measuring and calculating the aforementioned leakage currents Io and Ior, the measuring device 1 can also measure and calculate various values ​​such as current value, power value, the history of these values ​​changing over time, and fluctuations over time as electrical-related values ​​of the circuit. Furthermore, the measuring device 1 can also use these electrical-related values ​​of the circuit to inspect or monitor the electrical circuit under test.

[0113] Furthermore, the structure of the third measuring unit 31 is an example, and is not limited to the structure described above. For example... Figure 11 As shown, the third measurement unit 31 may also include an arithmetic unit 36 ​​to replace the phase angle detection unit 34 and the leakage current component calculation unit 35.

[0114] The calculation unit 36 ​​performs an integral operation based on synchronous detection based on the leakage current (waveform) detected by the leakage current detection unit 32 and the voltage (waveform) detected by the voltage detection unit 33 to calculate the leakage current component Ior (Io×cosθ) caused by the insulation resistance to ground. The integral operation based on synchronous detection is to calculate Io×cosθ by integrating the waveform within a specified range such as 0 to 180 degrees. A specific example is shown below. It should be noted that the integral operation based on synchronous detection is not limited to the following cases.

[0115] The arithmetic unit 36 ​​performs prescribed processing on the voltage value (voltage waveform) detected by the voltage detection unit 33 and the leakage current (current waveform) detected by the leakage current detection unit 32, outputting parameter signals of the logic signals. Furthermore, it performs full-wave rectification on the leakage current (current waveform) detected by the leakage current detection unit 32, quantizes the rectified current waveform using a continuous-mode ΔΣADC, measures the parameters of the sin and cos logic signals generated by the quantization transformation, and calculates the average value of the current waveform obtained through continuous-mode ΔΣADC processing. Specifically, the arithmetic unit 36 ​​performs logic processing on the voltage value (voltage waveform) detected by the voltage detection unit 33 to generate a first logic signal, performs logic processing on the leakage current (current waveform) detected by the leakage current detection unit 32 to generate a second logic signal, performs arithmetic processing on the first and second logic signals, and outputs a positive / negative or high / low signal (first signal). Additionally, the arithmetic unit 36 ​​generates zero-crossing points when the first logic signal changes and stores the time between the generated zero-crossing points. During a period less than half the stored time between the next zero-crossing point, the first logic signal is inverted, a phase transition of the first logic signal is performed, and the voltage waveform after phase transition and the second logic signal are processed to output a positive or negative or high / low signal (the second signal). The arithmetic unit 36 ​​performs quantization-based counting using a continuous-type ΔΣADC based on the first and second signals, thereby obtaining the average value of the desired type of current value. The desired type of current value includes alternating current, and the input current I[A], active current Ir=Icosθ[A], and reactive current IL-IC=Isinθ[A] can be calculated. Here, the aforementioned "active current Ir=Icosθ" is the leakage current component Ior caused by the insulation resistance to ground.

[0116] Based on the above structure, the leakage current component Ior caused by the insulation resistance to ground can be calculated without calculating the phase angle, which is an advantage.

[0117] <Regarding the structure and operation of the fourth measurement unit 41> The specific structure and operation of the fourth measuring unit 41 will be described. The fourth measuring unit 41 operates in the following fourth state, in which a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0118] Figure 12This is a block diagram showing the structure of the fourth measurement unit 41. Specifically, it is a block diagram showing the structure of the fourth measurement unit 41 and a diagram showing the wiring state of the fourth measurement unit 41 and the circuit under test when the control unit 55 identifies it as the fourth state and the selection processing unit 51 selects the fourth measurement unit 41. The fourth measurement unit 41 includes a leakage current detection unit 42, a voltage detection unit 43, a phase angle calculation unit 44, and a leakage current component calculation unit for ground insulation resistance (hereinafter referred to as the leakage current component calculation unit) 45.

[0119] The leakage current detection unit 42 detects the leakage current flowing through the tested circuit connected to a load. The leakage current detection unit 42 detects the leakage current flowing through the first phase, second phase, and third phase branching off from the delta connection (Δ) in the single-phase circuit. Hereinafter, the first phase will be referred to as the R phase, the second phase as the S phase, and the third phase as the T phase, but this designation is not limited. Furthermore, the leakage current measured by the leakage current detection unit 42 will be referred to as "Io" below, but this designation is not limited. Additionally, in this embodiment, the case where the S phase is grounded is described, but it could also be the case where the R phase or the T phase is grounded.

[0120] A zero-sequence current transformer (ZCT) 10 is connected to the leakage current detection unit 42. The zero-sequence current transformer 10 adopts a structure that uniformly clamps the circuit. For example, the zero-sequence current transformer 10 is composed of a portable, through-type split-type zero-sequence current transformer, which allows field personnel to easily install the zero-sequence current transformer 10 on the circuit. The leakage current detection unit 42 detects (calculates) the leakage current Io flowing through the circuit under test based on the signal measured by the zero-sequence current transformer 10.

[0121] The voltage detection unit 43 detects the voltage applied between the phases connected to the load. Figure 12 An example is shown where the load is arranged between phase R and phase T. Additionally, voltage detection unit 43 detects the voltage applied between phase R and phase T.

[0122] The phase angle calculation unit 44 calculates the phase angle based on the leakage current detected by the leakage current detection unit 42 and the voltage detected by the voltage detection unit 43. Specifically, the phase angle calculation unit 44 calculates the phase angle based on the waveform of the leakage current Io detected by the leakage current detection unit 42 and the voltage (e.g., reference voltage V) detected by the voltage detection unit 43. R-T The waveform of the signal is processed to detect the phase angle θ. For example, the phase angle calculation unit 44 is based on the reference voltage V. R-T The zero-crossing point of the leakage current Io and the zero-crossing point of the reference voltage V are detected. R-T The phase angle θ of the leakage current Io. Alternatively, the calculation of the phase angle can be performed using synchronous detection and DFT (Discrete Fourier Transform). The structure using synchronous detection will be described later.

[0123] The leakage current component calculation unit 45 uses the above formula (4) to calculate the leakage current component Ior caused by the insulation resistance to ground in the leakage current, based on the leakage current Io detected by the leakage current detection unit 42 and the phase angle θ calculated by the phase angle calculation unit 44.

[0124] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0125] After doing so, the measuring device 1, including the fourth measuring unit 41, can accurately calculate the Ior generated in the single-phase circuit branching from the delta connection based on the leakage current Io detected by the leakage current detection unit 42 and the phase angle (phase difference) calculated by the phase angle calculation unit 44. In other words, the fourth measuring unit 41 is a measuring unit used when a load is arranged between the ungrounded phases (between the R phase and the T phase) in the delta connection and it is used as a single-phase circuit.

[0126] For example, in a single-phase circuit where the load is connected between phases R and T, the voltage between phase E (ground) and phase R and phase ET is the same (e.g., 200 [V]). The load is arranged between phases R and T. The fourth measurement unit 41 detects the voltage V between the phases where the load is arranged, calculates the phase difference θ between the waveform of this voltage (sine wave) and the waveform of the leakage current Io input from the zero-sequence current transformer (ZCT) 10, and substitutes the leakage current Io and the phase difference θ into equation (4) to calculate Ior.

[0127] Here, the potential difference between phase R and phase T to ground is the same. In this case, even if floating capacitance is generated in phase R and phase T, the amount of floating capacitance generated in both is the same, and the floating capacitance will not become unbalanced.

[0128] Here, the reason why it will not become unbalanced will be explained. When the voltage detection unit 43 detects the voltage between phase R and phase T, and determines the reference point based on the detected voltage, as follows... Figure 14 As shown, the axis of phase R is located at a distance of 60 degrees from the reference point, and the axis of phase T is located at a distance of 120 degrees from the reference point. Furthermore, since the phase difference between the Ior (hereinafter referred to as Ior(r)) of phase R and the reference point is 60 degrees, Ior(r) appears on the axis of phase R. Since the phase difference between the Ior (hereinafter referred to as Ior(t)) of phase T and the reference point is 120 degrees, Ior(t) appears on the axis of phase T.

[0129] Furthermore, the Ioc of phase R (hereinafter referred to as Ioc(r)) occurs at a position 90 degrees from the axis of phase R, and therefore appears at a position of 150 degrees. The Ioc of phase T (hereinafter referred to as Ioc(t)) occurs at a position 90 degrees from the axis of phase T, and therefore appears at a position of 210 degrees. When Ioc(r) and Ioc(t) are in equilibrium, the Ioc(rt) resulting from the synthesis (vector synthesis) of Ioc(r) and Ioc(t) appears in the direction of 180 degrees from the reference axis. Figure 14 (in the "-X" direction). That is to say, the Ioc(r) generated in the R phase and the Ioc(t) generated in the T phase will not be out of balance.

[0130] In addition to measuring and calculating the aforementioned leakage currents Io and Ior, the measuring device 1 can also measure and calculate various values ​​such as current value, power value, the history of these values ​​changing over time, and fluctuations over time as electrical-related values ​​of the circuit. Furthermore, the measuring device 1 can also use these electrical-related values ​​of the circuit to inspect or monitor the electrical circuit under test.

[0131] Furthermore, the structure of the fourth measuring unit 41 is an example, and is not limited to the structure described above. For example... Figure 13 As shown, the fourth measurement unit 41 may also include an arithmetic unit 46 to replace the phase angle detection unit 44 and the leakage current component calculation unit 45.

[0132] The calculation unit 46 performs an integral operation based on synchronous detection based on the leakage current (waveform) detected by the leakage current detection unit 42 and the voltage (waveform) detected by the voltage detection unit 43 to calculate the leakage current component Ior (Io×cosθ / cos30°) caused by the insulation resistance to ground. The integral operation based on synchronous detection is a calculation that calculates Io×sinθ and then divides it by cos30° by integrating the waveform within a specified range of 90 to 270 degrees. A specific example is shown below. It should be noted that the integral operation based on synchronous detection is not limited to the following cases.

[0133] The arithmetic unit 46 performs prescribed processing on the voltage value (voltage waveform) detected by the voltage detection unit 43 and the leakage current (current waveform) detected by the leakage current detection unit 42, outputting parameter signals of the logic signals. Furthermore, it performs full-wave rectification on the leakage current (current waveform) detected by the leakage current detection unit 42, quantizes the rectified current waveform using a continuous-mode ΔΣADC, measures the parameters of the sin and cos logic signals generated by the quantization transformation, and calculates the average value of the current waveform obtained through continuous-mode ΔΣADC processing. Specifically, the arithmetic unit 46 performs logic processing on the voltage value (voltage waveform) detected by the voltage detection unit 43 to generate a first logic signal, performs logic processing on the leakage current (current waveform) detected by the leakage current detection unit 42 to generate a second logic signal, performs arithmetic processing on the first and second logic signals, and outputs a positive / negative or high / low signal (first signal). Additionally, the arithmetic unit 46 generates zero-crossing points when the first logic signal changes and stores the time between the generated zero-crossing points. During a period less than half the stored time between the next zero crossing, the first logic signal is inverted, a phase shift of the first logic signal is performed, and the voltage waveform after phase shift and the second logic signal are processed to output a positive or negative or high / low signal (the second signal). The arithmetic unit 46 performs quantization-based counting using a continuous-mode ΔΣADC based on the first and second signals, thereby obtaining the average value of the desired type of current value. The desired type of current value includes alternating current, and the input current I[A], active current Ir=Icosθ[A], and reactive current IL-IC=Isinθ[A] can be calculated. The arithmetic unit 46 divides the reactive current IL-IC=Isinθ by cos30° to calculate the leakage current component Ior caused by the insulation resistance to ground.

[0134] Based on the above structure, the leakage current component Ior caused by the insulation resistance to ground can be calculated without calculating the phase angle, which is an advantage.

[0135] Furthermore, in this embodiment, the first measurement unit 11, the second measurement unit 21, the third measurement unit 31, and the fourth measurement unit 41 are described as being configured independently, but this is not a limitation. For example, leakage current detection units 12, 22, 32, and 42 can be configured as one, voltage detection units 13, 23, 33, and 43 can be configured as one, phase angle calculation units 14, 24, 34, and 44 can be configured as one, and leakage current component calculation units 15, 25, 35, and 45 can be configured as one.

[0136] Figure 15 This is a diagram showing other structures of the measuring device 1c. The measuring device 1c consists of a measuring unit 101 and a selection processing unit 102.

[0137] The measurement unit 101 measures the electrical correlation values ​​of the circuit. These electrical correlation values ​​are related to the electrical correlation values ​​of the circuits branching off from the three-phase AC power supply connected in a star or delta configuration, or to the single-phase AC power distribution circuits branching off from the three-phase AC power supply.

[0138] The selection processing unit 102 selects one of any two or more of the following states: a first state, a second state, a third state, and a fourth state. In the first state, a three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first, second, or third phases and the neutral line. In the second state, a three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases. In the fourth state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0139] When the selection processing unit 102 selects either the first state or the third state, the measurement unit 101 calculates one of the circuit electrical related values ​​using Ior = Io × cosθ, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. This value is the leakage current component Ior, which is the leakage current component Ior caused by the insulation resistance to ground, included in the leakage current Io. When the selection processing unit 102 selects the second state, the measurement unit 101 calculates the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between the first, second, or third phases connected to the load and the neutral line. The phase angle θ calculated from the voltage between the phases is used to calculate one of the electrical related values ​​of the circuit, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io. When the fourth state is selected by the selection processing unit 102, the measurement unit 101 calculates one of the electrical related values ​​of the circuit, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load, using Ior=Io×sinθ / cos30°.

[0140] <Relevant Measurement Methods> Here, the measurement method using measuring device 1 will be described. Figure 16 This is a flowchart illustrating the steps of the measurement method.

[0141] In step ST1, the selection processing unit 51 selects any one of a plurality of measurement units that measure the electrical correlation value of the circuit using different structures. The electrical correlation value of the circuit is the electrical correlation value of the circuit branching off from the measured circuit that is connected to a three-phase AC power supply with a star connection or a delta connection, or the circuit that branches off from the three-phase AC power supply to a single-phase AC power supply and distributes the power (selection processing step).

[0142] In step ST2, the measurement unit 2 performs measurement using any one of the first measurement unit 11 to the fourth measurement unit 41 selected in the selection process step (measurement step).

[0143] Here, the first measurement unit 11 uses the electrical correlation value of the first structure measurement circuit, which is the electrical correlation value of the circuit that branches off from the tested circuit that is connected to a three-phase AC power supply in a star configuration, and branches off from the three-phase AC power supply to a single-phase AC power supply for power distribution.

[0144] The second measurement unit 21 uses the electrical correlation value of the second structure measurement circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the tested circuit which is connected to a three-phase AC power supply in a star configuration, and the circuit branching off from the three-phase AC power supply into a single-phase AC power supply for power distribution.

[0145] The third measurement unit 31 uses a third structure measurement circuit to measure electrical correlation values, which are electrical correlation values ​​with the electrical correlation values ​​of the measured circuit branching off from the three-phase AC power supply connected in a delta configuration, and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution.

[0146] The fourth measurement unit 41 uses the fourth structure measurement circuit to measure the electrical correlation value, which is the electrical correlation value of the circuit that branches off from the measured circuit that is connected to a three-phase AC power supply with a delta connection, and branches off from the three-phase AC to a single-phase AC circuit for power distribution.

[0147] The measurement unit 2 is composed of any two or more of the first measurement unit 11 to the fourth measurement unit 41. This allows the measurement method to switch to the measurement unit (the first measurement unit 11 to the fourth measurement unit 41) suitable for the three-phase AC power supply (the first to fourth states described above) when converting three-phase AC power from a three-phase AC power supply to single-phase AC power and connecting a load to a single-phase AC power supply line. Furthermore, it enables accurate calculation of the Ior generated on that power supply line.

[0148] In addition, the first measurement unit 11 is selected in the following first state when the processing step is selected. In the first state, the three-phase AC power supply with the first phase, the second phase, the third phase and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first phase, the second phase or the third phase and the neutral line.

[0149] In addition, the second measurement unit 21 is selected in the following second state of the processing step. In the second state, the three-phase AC power supply with the first, second and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second and third phases.

[0150] In addition, the third measurement unit 31 is selected in the following third state of the processing step. In the third state, the three-phase AC power supply with the first, second and third phases delta connected and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases.

[0151] In addition, the fourth measurement unit 41 is selected in the following fourth state as the processing step. In the fourth state, the three-phase AC power supply with the first, second and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0152] In addition, the first measuring unit 11, as the first structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between any one of the first, second, or third phases with the load and the neutral line, using Ior=Io×cosθ.

[0153] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0154] In addition, the second measurement unit 21, as a second structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the two phases connected to the load, using Ior=Io×sinθ / cos60°.

[0155] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0156] In addition, the third measurement unit 31, as the third structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load, using Ior=Io×cosθ.

[0157] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0158] In addition, the fourth measurement unit 41, as the fourth structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between the phases connected to the load, using Ior=Io×sinθ / cos30°.

[0159] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0160] Next, other measurement methods using measuring device 1 will be described. Figure 17 This is a flowchart illustrating the steps of other measurement methods.

[0161] In step ST101, the measurement unit 101 measures the electrical correlation value of the circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the three-phase AC power supply connected by a star connection or a delta connection, or the circuit branching off from the three-phase AC power supply into a single-phase AC power supply for power distribution (measurement step).

[0162] In step ST102, the selection processing unit 102 selects one state from any two or more of the following first, second, third, and fourth states. In the first state, a three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first, second, or third phases and the neutral line. In the second state, a three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases. In the fourth state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases (selection processing step).

[0163] When the first or third state is selected in the selection process, the measurement unit 101 calculates one of the electrical related values ​​of the circuit using Ior = Io × cosθ, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. This value is the leakage current component Ior, which is the leakage current component Ior caused by the insulation resistance to ground, included in the leakage current Io. When the second state is selected in the selection process, the measurement unit 101 calculates the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between the first, second, or third phases connected to the load and the neutral line. The phase angle θ calculated from the voltage between the phases is used to calculate one of the electrical related values ​​of the circuit, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io. When the fourth state is selected in the selection process, the measurement unit 101 calculates one of the electrical related values ​​of the circuit, namely the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load, using Ior=Io×sinθ / cos30°.

[0164] (Measurement Procedure) The following measurement procedure mainly consists of the following steps and is executed by computer 500 (hardware). In this measurement procedure, when the three-phase AC output from the three-phase AC power supply is converted to single-phase AC and a load is connected to the single-phase AC power supply line, the measurement unit switches to the state suitable for the three-phase AC power supply and accurately calculates the Ior generated on the power supply line.

[0165] Step 1: Select any one of the multiple measuring units that measure the electrical correlation values ​​of the circuit using different structures. The electrical correlation value of this circuit is the electrical correlation value of the circuit under test branching off from the three-phase AC power supply connected by a star or delta connection, or branching off from the three-phase AC power supply into a single-phase AC power supply for power distribution (select processing step).

[0166] Step 2: Perform measurement using any one of the first measurement unit 11 to the fourth measurement unit 41 selected in the selection process step (measurement step).

[0167] Here, the first measurement unit 11 uses the electrical correlation value of the first structure measurement circuit, which is the electrical correlation value of the circuit that branches off from the tested circuit that is connected to a three-phase AC power supply in a star configuration, and branches off from the three-phase AC power supply to a single-phase AC power supply for power distribution (first measurement step).

[0168] The second measurement unit 21 uses the second structure to measure the electrical correlation value of the circuit. The electrical correlation value of the circuit is the electrical correlation value of the circuit branching out from the three-phase AC power supply connected in a star configuration, and branching out from the three-phase AC power supply into a single-phase AC power supply for power distribution (second measurement step).

[0169] The third measurement unit 31 uses a third structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical correlation values ​​of the circuit branching off from the three-phase AC power supply connected in a delta configuration, and the circuit branching off from the three-phase AC power supply into a single-phase AC power supply for power distribution (third measurement step).

[0170] The fourth measurement unit 41 uses the fourth structure measurement circuit to measure the electrical correlation value, which is the electrical correlation value of the circuit that branches off from the three-phase AC power supply connected in a delta connection and branches off from the three-phase AC power supply to the single-phase AC power supply for power distribution (fourth measurement step).

[0171] The measurement unit 2 is composed of any two or more of the first measurement unit 11 to the fourth measurement unit 41.

[0172] Here, using Figure 18 Explain the structure and operation of the computer 500. For example... Figure 18 As shown, the processor 501, memory 502, storage device 503, input / output interface 504, and communication interface 505 are connected via bus A to form a computer 500, and the functions and / or methods described in this disclosure are realized through the cooperation of the above-mentioned components.

[0173] The input / output interface 504 is connected to a display screen for showing various information, a touch panel for receiving user input, and other similar devices. The touch panel is positioned on the front surface of the display screen. Therefore, users can perform intuitive operations by touching icons on the display screen with their fingers. It should be noted that the touch panel may not be positioned on the front surface of the display screen. Alternatively, instead of a touch panel, a keyboard and mouse can be connected to the input / output interface 504, or the keyboard and mouse can be connected together with the touch panel. Furthermore, a speaker for outputting sound to the outside and a microphone for inputting external sound can also be connected to the input / output interface 504.

[0174] The display screen is composed of liquid crystal display screen or organic electroluminescent (EL) display screen, etc., and displays various information under the control of processor 501.

[0175] Memory 502 consists of Random Access Memory (RAM). Random Access Memory can be either volatile or non-volatile.

[0176] Storage device 503 is composed of read-only memory (ROM). ROM is composed of non-volatile memory, such as a hard disk drive (HDD) or a solid state drive (SSD). Storage device 503 stores various programs, such as the measurement programs implemented in steps 1 to 2 above.

[0177] For example, processor 501 controls the overall operation of computer 500. Processor 501 is a computing device that loads the operating system and various programs that implement various functions from storage device 503 into memory 502 and executes the instructions contained in the loaded programs.

[0178] Specifically, when the processor 501 receives an operation from the user, the processor 501 reads the program stored in the storage device 503 (e.g., the measurement program in this embodiment), expands the read program into the memory 502, and executes the program. In addition, by executing the measurement program by the processor 501, the functions of the first measurement unit 11, leakage current detection units 12, 22, 32, 42, voltage detection units 13, 23, 33, 43, phase angle calculation units 14, 24, 34, 44, ground insulation resistance leakage current component calculation units (leakage current component calculation units) 15, 25, 35, 45, second measurement unit 21, third measurement unit 31, fourth measurement unit 41, and selection processing unit 51 can be realized.

[0179] Here, the structure of processor 501 will be described. Processor 501 is implemented, for example, by a central processing unit (CPU), a microprocessor unit (MPU), a graphics processing unit (GPU), various other computing devices, or combinations thereof.

[0180] Furthermore, in order to implement the functions and / or methods described in this disclosure, some or all of the functions of the processor 501, memory 502, storage device 503, etc., can be constituted by dedicated hardware, namely the processing circuit 601, such as... Figure 19As shown. The processing circuit 601 is, for example, a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof.

[0181] Furthermore, while processor 501 has been described as a single component, it is not limited to this; a processor may also be a collection of multiple physically separate processors. In this specification, the program described as being executed by processor 501, or the instructions contained within that program, may be executed by a single processor 501, or may be executed distributed among multiple processors. Additionally, the program executed by processor 501, or the instructions contained within that program, may also be executed by multiple virtual processors.

[0182] The communication interface 505 is an interface that conforms to the specified communication standard and communicates with external devices via wired or wireless means.

[0183] After doing so, by executing the measurement program by the computer 500, when the three-phase AC output from the three-phase AC power supply is converted into single-phase AC and a load is connected to the single-phase AC power supply line, the measurement program can select the appropriate state of the three-phase AC power supply (the first state to the fourth state mentioned above) (the first measurement step to the fourth measurement step mentioned above), and can accurately calculate the Ior generated on the power supply line.

[0184] In addition, the first measurement unit 11 is selected in the following first state when the processing step is selected. In the first state, the three-phase AC power supply with the first phase, the second phase, the third phase and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first phase, the second phase or the third phase and the neutral line.

[0185] In addition, the second measurement unit 21 is selected in the following second state of the processing step. In the second state, the three-phase AC power supply with the first, second and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second and third phases.

[0186] In addition, the third measurement unit 31 is selected in the following third state of the processing step. In the third state, the three-phase AC power supply with the first, second and third phases delta connected and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases.

[0187] In addition, the fourth measurement unit 41 is selected in the following fourth state as the processing step. In the fourth state, the three-phase AC power supply with the first, second and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

[0188] In addition, the first measuring unit 11, as the first structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between any one of the first, second, or third phases with the load and the neutral line, using Ior=Io×cosθ.

[0189] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0190] In addition, the second measurement unit 21, as a second structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the two phases connected to the load, using Ior=Io×sinθ / cos60°.

[0191] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0192] In addition, the third measurement unit 31, as the third structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load, using Ior=Io×cosθ.

[0193] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0194] In addition, the fourth measurement unit 41, as the fourth structure, calculates the leakage current component Ior caused by the insulation resistance to ground in the leakage current Io based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated by the voltage applied between the phases connected to the load, using Ior=Io×sinθ / cos30°.

[0195] It should be noted that the leakage current, voltage, phase angle, and leakage current component caused by insulation resistance to ground mentioned above are all included in the circuit electrical related values.

[0196] In addition, the measurement procedure is not limited to the above, and may also consist mainly of the following steps and be executed by computer 500 (hardware).

[0197] Step 101: Measure the electrical correlation values ​​of the circuit. These electrical correlation values ​​are related to the electrical correlation values ​​of the circuits branching off from the three-phase AC power supply connected in a star or delta configuration, and the circuits branching off from the three-phase AC power supply into single-phase AC power for distribution (measurement steps).

[0198] Step 102: Select one of the following states: First, Second, Third, and Fourth. In the First state, a three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first, second, or third phases and the neutral line. In the Second state, a three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the Third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases. In the Fourth state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases (selecting the processing step).

[0199] In the measurement process, When the first or third state is selected in the processing steps, based on the leakage current Io flowing through the tested circuit and the phase angle θ calculated from the voltage applied between any one of the first, second, or third phases with load and the neutral line, one of the circuit's electrical related values ​​is calculated using Ior = Io × cosθ. This value is the leakage current component Ior, caused by the insulation resistance to ground, included in the leakage current Io. When the second state is selected in the processing steps, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the two phases connected to the load, one of the electrical related values ​​of the circuit is calculated using Ior = Io × sinθ / cos60°, which is the leakage current component Ior caused by the insulation resistance to ground included in the leakage current Io. When the fourth state is selected in the processing steps, based on the leakage current Io flowing through the circuit under test and the phase angle θ calculated from the voltage applied between the phases connected to the load, one of the electrical related values ​​of the circuit is calculated using Ior = Io × sinθ / cos30°, which is the leakage current component Ior caused by the insulation resistance to ground included in the leakage current Io. - Symbol Explanation - 1 Measuring device 2 Measurement Department 10. Zero-sequence current transformer (ZCT) 11 First Measurement Department Leakage current detection unit (12, 22, 32, 42) Voltage detection units 13, 23, 33, 43 Phase angle calculation unit (14, 24, 34, 44) Calculation of leakage current component of insulation resistance to ground at values ​​of 15, 25, 35, and 45 (Leakage current component calculation section) Arithmetic units 16, 26, 36, 46 21 Second Measurement Department 31 Third Measurement Department 41 Fourth Measurement Department 51. Select Processing Department.

Claims

1. A measuring device, characterized in that: It includes a measurement unit and a selection processing unit. The measurement unit is composed of any two or more of a first measurement unit, a second measurement unit, a third measurement unit, and a fourth measurement unit. The first measurement unit utilizes electrical correlation values ​​from a first-structure measurement circuit. These electrical correlation values ​​are related to the electrical connections of the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and then branching off into single-phase AC circuits for power distribution. The second measurement unit utilizes electrical correlation values ​​from a second-structure measurement circuit. These electrical correlation values ​​are related to the electrical connections of the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and then branching off into single-phase AC circuits for power distribution. The electrical-related values ​​are as follows: the third measurement unit measures the electrical-related values ​​using a third-structure circuit, which are related to the electrical-related values ​​of the tested circuit branching off from a three-phase AC power supply connected in a delta configuration, and the electrical-related values ​​of the circuit branching off from a three-phase AC power supply branching off to a single-phase AC power supply branching off to a ... The selection processing unit selects any one of the measurement units.

2. The measuring device according to claim 1, characterized in that: In the following first state, the selection processing unit selects the first measurement unit. In this first state, the three-phase AC power supply with the first phase, second phase, third phase, and neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first phase, second phase, or third phase and the neutral line. In the following second state, the selection processing unit selects the second measurement unit. In this second state, the three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the following third state, the selection processing unit selects the third measurement unit. In this third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test. The load is connected to the grounded phase and any one of the ungrounded phases. In the following fourth state, the selection processing unit selects the fourth measurement unit. In the fourth state, a three-phase AC power supply with the first, second, and third phases delta-connected and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases.

3. The measuring device according to claim 2, characterized in that: The first measuring unit, as the first structure, calculates the leakage current component caused by the insulation resistance to ground, based on the leakage current flowing through the tested circuit and the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. The second measurement unit, as the second structure, calculates the leakage current component caused by the insulation resistance to ground within the leakage current, based on the leakage current flowing through the tested circuit and the voltage applied between the two phases connected to the load. The third measuring unit, as the third structure, calculates the leakage current component caused by the insulation resistance to ground within the leakage current based on the leakage current flowing through the tested circuit and the voltage applied between the phases connected to the load. The fourth measuring unit, as the fourth structure, calculates the leakage current component caused by the insulation resistance to ground in the leakage current based on the leakage current flowing through the circuit under test and the voltage applied between the phases connected to the load.

4. A measuring device, characterized in that: It includes a measurement department and a selection processing department. The electrical correlation value of the measuring circuit of the measuring unit is a value related to the electrical properties of the circuit branching off from the tested circuit connected to a three-phase AC power supply with a star or delta connection, or from the three-phase AC branching off to a single-phase AC circuit for power distribution. The selection processing unit selects one state from any two or more of the following states: a first state, a second state, a third state, and a fourth state. In the first state, a three-phase AC power supply with the first, second, and third phases and the neutral line connected in a star configuration is connected to the circuit under test, and the load is connected to any one of the first, second, or third phases and the neutral line. In the second state, a three-phase AC power supply with the first, second, and third phases connected in a star configuration is connected to the circuit under test, and the load is connected to any two of the first, second, and third phases. In the third state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the grounded phase and any one of the ungrounded phases. In the fourth state, a three-phase AC power supply with the first, second, and third phases connected in a delta configuration and any one phase grounded is connected to the circuit under test, and the load is connected to the two ungrounded phases. When the selection processing unit selects either the first state or the third state, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between any one of the first, second, or third phases connected to the load and the neutral line. This value is the leakage current component caused by the insulation resistance to ground included in the leakage current. When the second state is selected by the selection processing unit, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between the two phases connected to the load, namely, the leakage current component caused by the insulation resistance to ground included in the leakage current. When the fourth state is selected by the selection processing unit, the measurement unit calculates one of the electrical related values ​​of the circuit based on the leakage current flowing through the circuit under test and the voltage applied between the phases connected to the load, namely the leakage current component caused by the insulation resistance to ground included in the leakage current.

5. A measurement method, characterized in that: It includes the selection of processing steps and measurement steps. In the selection process step, one of several measuring units is selected from multiple measuring units that measure electrical correlation values ​​using different circuit structures. These electrical correlation values ​​are related to the electrical properties of the measured circuit branching off from a three-phase AC power supply connected in a star or delta configuration, or to a circuit branching off from a three-phase AC power supply into a single-phase AC power supply for distribution. In the measurement step, the measurement is performed using the measurement unit selected by the selection processing step. The measuring unit is composed of any two or more of the following: a first measuring unit, a second measuring unit, a third measuring unit, and a fourth measuring unit. The first measuring unit uses a first-structure measuring circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a star configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The second measurement unit utilizes a second-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and between the three-phase AC branching off into single-phase AC circuits for power distribution. The third measurement unit utilizes a third-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a delta configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The fourth measurement unit uses the fourth structure to measure the electrical correlation value of the circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the tested circuit connected to a three-phase AC power supply with delta connection, and the circuit branching off from the three-phase AC power supply to a single-phase AC power supply for power distribution.

6. A measurement procedure, characterized in that: It is used to enable the computer to perform selection processing steps and measurement steps. In the selection process step, one of several measuring units is selected from multiple measuring units that measure electrical correlation values ​​using different circuit structures. These electrical correlation values ​​are related to the electrical properties of the measured circuit branching off from a three-phase AC power supply connected in a star or delta configuration, or to a circuit branching off from a three-phase AC power supply into a single-phase AC power supply for distribution. In the measurement step, the measurement is performed using the measurement unit selected by the selection processing step. The measuring unit is composed of any two or more of the following: a first measuring unit, a second measuring unit, a third measuring unit, and a fourth measuring unit. The first measuring unit uses a first-structure measuring circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a star configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The second measurement unit utilizes a second-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from a three-phase AC power supply connected in a star configuration, and between the three-phase AC branching off into single-phase AC circuits for power distribution. The third measurement unit utilizes a third-structure measurement circuit to measure electrical correlation values. These electrical correlation values ​​are related to the electrical connections between the measured circuit branching off from the three-phase AC power supply connected in a delta configuration and the circuit branching off from the three-phase AC power supply into single-phase AC power for distribution. The fourth measurement unit uses the fourth structure to measure the electrical correlation value of the circuit. This electrical correlation value is related to the electrical correlation value of the circuit branching off from the tested circuit connected to a three-phase AC power supply with delta connection, and the circuit branching off from the three-phase AC power supply to a single-phase AC power supply for power distribution.

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