Insulation monitoring device, operation test system for insulation monitoring device, operation test method for insulation monitoring device, and operation test program for insulation monitoring device

Abstract

To implement an insulation monitoring device performance test and accuracy test safely and accurately in a short time with a simple configuration.SOLUTION: An insulation monitoring device comprises: a reference voltage detection unit 11 that detects a voltage applied between any two phases of an electric path 3 of an AC circuit, and acquires the voltage as a reference voltage Vref; a test current output unit 15 that can output a test current It synchronizing with the reference voltage Vref to a test current output line 5; a leak current detection unit 13 that acquires current detection as a measurement leak current Iom on the basis of a result of the current detection of the current path 3 and the test current output line 5; and a computation control unit 16 that generates information on detection accuracy of the leak current detection unit 13 on the basis of a first measurement leak current Iom (1) acquired by the leak current detection unit 13 when the test current It is not outputted, and a second measurement leak current Iom (2) acquired by the leak current detection unit 13 when the test current It is outputted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an insulation monitoring device, an operation test system for an insulation monitoring device, an operation test method for an insulation monitoring device, and an operation test program for an insulation monitoring device.

Background Art

[0002] An insulation monitoring device for monitoring the ground fault of a low-voltage circuit contributes to improving the electrical safety level by constantly monitoring the insulation of the low-voltage circuit in a high-voltage residential facility, thereby preventing electric shock, fire accidents, power outage failures, etc. caused by leakage. Regarding its leakage detection function, the insulation monitoring device is legally obliged to regularly conduct an operation test and an accuracy (error) test. When conducting such an operation test and accuracy test of the insulation monitoring device, in order to accurately measure and determine, it is necessary to remove the ZCT from the circuit being monitored and measured, and the work near the charging part may be dangerous. There is also a method of powering off the measurement circuit, but it is practically difficult to power off the customer's equipment.

[0003] On the other hand, a test current generation device and a test device for an insulation monitoring device that can perform an operation test and an accuracy test of the insulation monitoring device while the monitored circuit remains in the live state without powering it off have been disclosed (see Patent Document 1). The test current generation device of Patent Document 1 generates a test current that can obtain a target value when added to the resistive current component included in the zero-phase current based on the detection information of the zero-phase current, the target value of the resistive current component related to the detection of the insulation monitoring device by flowing a test current, and the reference phase information preset as information for specifying the phase of the resistive current component.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the test current generator and insulation monitoring device described in Patent Document 1 above, the calculation of the output value of the test current depends on the current value of the zero-sequence current detected by the ground fault current detection device. If the accuracy of the ground fault current detection device (current value and / or phase difference) is inaccurate, errors will occur in the calculation of the test current to be generated. As a result, the output test current will deviate from the target value that should be output, making it impossible to perform accurate accuracy testing. Furthermore, in such cases, the test current value that should be output cannot be output for the alarm generation current value, which is set as the current value at which an alarm should be issued as if a ground fault has occurred, making it impossible to perform accurate alarm operation testing.

[0006] Furthermore, a circuit was required to calculate the test current to be output, which resulted in a complex configuration.

[0007] The present invention was made to solve these problems, and its objective is to provide an insulation monitoring device, an insulation monitoring device operation test system, an insulation monitoring device operation test method, and an insulation monitoring device operation test program that can perform operation tests and accuracy tests of the insulation monitoring device safely and accurately in a short time with a simple configuration. [Means for solving the problem]

[0008] To achieve the above objectives, the insulation monitoring device according to the present invention includes: a reference voltage detection unit that detects the voltage applied between any two phases of a monitored circuit of an AC circuit and acquires it as a reference voltage; a test current output unit that can output a test current synchronized with the reference voltage to a test current output line; a leakage current detection unit that acquires a measured leakage current based on the current detection results of the monitored circuit and the test current output line; a calculation unit that generates information regarding the detection accuracy of the leakage current detection unit based on a first measured leakage current acquired by the leakage current detection unit when the test current is not outputting, and a second measured leakage current acquired by the leakage current detection unit when the test current is outputting; A phase difference calculation unit for detecting the phase difference of the measured leakage current with respect to the reference voltage, Equipped with The leakage current detection unit calculates the effective value of the first measured leakage current and the effective value of the second measured leakage current. The calculation unit performs a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected by the phase difference calculation unit for the first measured leakage current, the second measured phase difference detected by the phase difference calculation unit for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current to calculate the leakage current change. .

[0009] To achieve the above objectives, the operation test system for an insulation monitoring device according to the present invention includes: a reference voltage detection unit that detects the voltage applied between any two phases of a monitored circuit of an AC circuit and acquires it as a reference voltage; a test current output unit that can output a test current synchronized with the reference voltage to a test current output line; a leakage current detection unit that detects the leakage current, including the test current, flowing through the monitored circuit and the test current output line and acquires it as a measured leakage current; a calculation unit that generates information regarding the detection accuracy of the leakage current detection unit based on a first measured leakage current detected by the leakage current detection unit when the test current is not being output and a second measured leakage current detected by the leakage current detection unit when the test current is being output; A phase difference calculation unit for detecting the phase difference of the measured leakage current with respect to the reference voltage, Equipped with The leakage current detection unit calculates the effective value of the first measured leakage current and the effective value of the second measured leakage current. The calculation unit performs a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected by the phase difference calculation unit for the first measured leakage current, the second measured phase difference detected by the phase difference calculation unit for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current to calculate the change in leakage current. .

[0010] To achieve the above objective, the present invention provides an operational test method for an insulation monitoring device, wherein a computer generates information regarding the detection accuracy of a leakage current in an AC circuit that is to be monitored, and the method comprises: a reference voltage detection step of detecting a voltage applied between any two phases of the circuit to be monitored and acquiring it as a reference voltage; a first measured leakage current acquisition step of detecting a leakage current flowing through the circuit to be monitored and acquiring it as a first measured leakage current; a test current output step of outputting a test current synchronized with the reference voltage to a test current output line; a second measured leakage current acquisition step of detecting a leakage current including the test current flowing through the circuit to be monitored and the test current output line when the test current is being output and acquiring it as a second measured leakage current; a calculation step of generating information regarding the detection accuracy based on the first measured leakage current and the second measured leakage current; and the calculation of the reference voltage 1 Phase difference of measured leakage current and the phase difference of the second measured leakage current with respect to the reference voltage The process includes a phase difference calculation step for detecting the First step in acquiring measured leakage current. This is the effective value of the first measured leakage current. The second measurement leakage current acquisition step is performed by calculating the following: The effective value of the second measured leakage current is calculated, and the calculation step is performed for the first measured leakage current, the phase difference calculation In the process The phase difference calculation is performed using the detected first measured phase difference and the second measured leakage current. In the process Based on the detected second measurement phase difference, the effective value of the first measurement leakage current, and the effective value of the second measurement leakage current, the first measurement leakage current and the second measurement leakage current are vector-operated to calculate the change in leakage current.

[0011] To achieve the above objective, the operation test program for an insulation monitoring device implemented by a computer according to the present invention includes: a reference voltage detection step of detecting the voltage applied between any two phases of the circuit to be monitored and acquiring it as a reference voltage; a first measured leakage current acquisition step of detecting the leakage current flowing through the circuit to be monitored and acquiring it as a first measured leakage current; a test current output step of outputting a test current synchronized with the reference voltage to a test current output line; a second measured leakage current acquisition step of detecting the leakage current including the test current flowing through the circuit to be monitored and the test current output line when the test current is being output and acquiring it as a second measured leakage current; a calculation step of generating information regarding the detection accuracy based on the first measured leakage current and the second measured leakage current; and the reference voltage 1 Phase difference of measured leakage current and the phase difference of the second measured leakage current with respect to the reference voltage The process includes a phase difference calculation step for detecting the First step in acquiring measured leakage current. This is the effective value of the first measured leakage current. The second measurement leakage current acquisition step includes calculating the following: The calculation step includes calculating the effective value of the second measured leakage current, and the calculation step includes calculating the phase difference for the first measured leakage current. In the process The phase difference calculation is performed using the detected first measured phase difference and the second measured leakage current. In the process This includes calculating the change in leakage current by performing a vector operation on the first measured leakage current and the second measured leakage current based on the detected second measured phase difference, the effective value of the first measured leakage current, and the effective value of the second measured leakage current. [Effects of the Invention]

[0012] According to the present invention using the above means, operational tests and accuracy tests of the insulation monitoring device can be performed safely and accurately in a short time with a simple configuration. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows a system configuration in which an insulation monitoring device according to one embodiment of the present invention is applied to an AC circuit. [Figure 2]FIG. 1 shows as configuration examples of the transformer (a) single-phase three-wire type, (b) three-phase three-wire type (delta connection), and (c) three-phase three-wire type (star connection). [Figure 3] FIG. 3 shows an example of a screen display of the display unit during the operation test execution. [Figure 4] FIG. 6 is a block diagram showing the configuration of the arithmetic control unit and the input / output configuration of the operation test executed by the arithmetic control unit. [Figure 5] FIG. 9 shows a vector of leakage current generated in the measured electric wire path when the test current is not output in the single-phase three-wire type. [Figure 6] FIG. 12 shows (a) a vector of generated leakage current generated in the measured electric wire path when the test current is output in the single-phase three-wire type, and (b) a vector of measured leakage current accurately detected. [Figure 7] FIG. 15 shows (a) a vector of generated leakage current generated in the measured electric wire path and measured leakage current inaccurately detected when the test current is output in the single-phase three-wire type, and (b) a vector of the change in leakage current of the measured leakage current inaccurately detected. [Figure 8] FIG. 18 shows a diagram in which the vector of the change in leakage current in FIG. 7(b) is decomposed into direct components. [Figure 9] FIG. 21 shows in the three-phase three-wire type (delta connection) (a) a vector of generated leakage current generated in the measured electric wire path when the test current is not output, (b) a diagram showing the leakage current generated in the measured electric wire path when the test current is output, and (c) a vector of the measured leakage current detected when the test current is output and the change in leakage current. [Figure 10] FIG. 24 shows in the three-phase three-wire type (star connection) (a) a vector of generated leakage current generated in the measured electric wire path when the test current is not output, (b) a diagram showing the leakage current generated in the measured electric wire path when the test current is output, and (c) a vector of the measured leakage current detected when the test current is output and the change in leakage current. [Figure 11] FIG. 27 is a flowchart relating to the operation test routine of the insulation monitoring device in the present embodiment. [Figure 12] This figure shows a first modified example of the system configuration of an insulation monitoring device in one embodiment of the present invention. [Figure 13] This is a flowchart relating to the control routine for the operational test of the first modified example. [Figure 14] This is a block diagram of the computer configuration. [Figure 15] Hardware configuration block. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] <System Configuration> Figure 1 shows a system configuration in which an insulation monitoring device according to one embodiment of the present invention is applied to an AC circuit. Figure 2 shows examples of the transformer configuration in Figure 1, including (a) single-phase three-wire system, (b) three-phase three-wire system (delta connection), and (c) three-phase three-wire system (star connection). Figure 3 shows an example of the screen display of the display unit 17 during operation testing.

[0016] The insulation monitoring device 1 according to this embodiment is installed inside a substation (cubicle) and, as shown in Figure 1, is a device that constantly monitors the ground-to-ground insulation of electrical equipment supplied from the secondary side (low-voltage side) circuit (monitored circuit) 3 of the transformer 2 of the substation. The insulation monitoring device 1 has the function of measuring the leakage current Io of the circuit 3 in a live state without temporarily deactivating the monitored circuit 3, detecting monitoring information such as abnormal leakage current, and notifying the measurement results and detected monitoring information to an external party. The leakage current Io includes the resistive component leakage current Ior, which is directly related to the insulation resistance and is caused by the ground-to-ground insulation resistance, and the capacitive component leakage current Ioc, which is caused by the ground capacitance. The insulation monitoring device 1 of this embodiment employs an Ior measurement method that can measure not only the leakage current Io but also the resistive component leakage current Ior and the capacitive component leakage current Ioc depending on the wiring method of the circuit 3.

[0017] As shown in Figure 1, the insulation monitoring device 1 is applied to the three-wire circuit 3 on the secondary side of the transformer 2. The connection method between the transformer 2 and the circuit 3 can be any of the following, as shown in Figure 2: single-phase three-wire (Figure 2(a)), three-phase three-wire delta connection (Figure 2(b)), or three-phase three-wire star connection (Figure 2(c)). The connection method is selected and stored in advance in the settings of the insulation monitoring device 1.

[0018] As shown in Figure 1, the insulation monitoring device 1 comprises a reference voltage detection unit 11, a zero-phase current transformer 12, a leakage current detection unit 13 connected to the zero-phase current transformer 12, an operation test selection unit 14, a test current output unit 15, a calculation control unit (calculation unit) 16, a display unit 17, and an alarm output unit 18. The insulation monitoring device 1 also has the function of communicating with a portable measurement terminal 4 by wired or wireless means and acquiring terminal measurement information from the portable measurement terminal 4. The portable measurement terminal 4 is, for example, a calibrated handheld meter equipped with a clamp 41 that can penetrate any electrical circuit, and is a terminal that can detect and measure the current of the clamped electrical circuit, and display the measurement results on a display unit 42 provided on the front panel of the handheld meter, or output them externally as terminal measurement information.

[0019] The reference voltage detection unit 11 detects the voltage applied between any two of the three phases of the circuit 3, which is electrically connected to those two phases, as the reference voltage Vref. It calculates the effective value RMS(Vref), frequency F(Vref), and phase θ(Vref) of the reference voltage Vref and outputs them to the test current output unit 15 and the calculation control unit 16. The frequency F(Vref) of the reference voltage Vref is used when generating the test current It, which will be described later (hereinafter simply referred to as the reference frequency). The phase θ(Vref) of the reference voltage Vref is used as the reference phase when calculating the phase difference, which will be described later (hereinafter simply referred to as the reference phase).

[0020] The zero-phase current transformer 12 is a so-called ZCT, which penetrates the circuit 3 in one go and detects the leakage current Io flowing through the circuit 3. In addition to the circuit 3, the zero-phase current transformer 12 also penetrates the test current output line 5, which will be described later. Hereafter, the circuit 3 and the test current output line 5, which the zero-phase current transformer 12 penetrates in one go, will be collectively referred to as the measured power line 6. That is, the zero-phase current transformer 12 is capable of detecting the leakage current Io flowing through the measured power line 6, and if the test current It, which will be described later, is output, it will detect the leakage current Io including the test current It. Note that the leakage current Io actually occurring in the circuit 3 and the test current output line 5 will be referred to as the generated leakage current Ioa, and the leakage current detected by the zero-phase current transformer 12 will be referred to as the measured leakage current Iom, to distinguish between the two.

[0021] The leakage current detection unit 13 acquires the measured leakage current Iom based on the current detection results of the circuit 3 and the test current output line 5, i.e., the power line 6 under test. Specifically, the leakage current detection unit 13 is electrically connected to the zero-phase current transformer 12 and acquires the leakage current Io of the power line 6 under test detected by the zero-phase current transformer 12 as the measured leakage current Iom, and calculates the effective value RMS(Iom) of the measured leakage current Iom. In this embodiment, while the insulation monitoring device 1 is performing an operation test, the leakage current detection unit 13 acquires the first measured leakage current Iom(1) when the test current It is not output (no output state) and the second measured leakage current Iom(2) when the test current It is output (output state), calculates their effective values ​​RMS(Iom(1)) and RMS(Iom(2)), and outputs them to the calculation control unit 16.

[0022] The operation test selection unit 14 is, for example, a switch provided on the front panel of the insulation monitoring device 1. The operation test of the insulation monitoring device 1 is started and ended by the operator turning the switch on or off on the operation test selection unit 14. Here, the operation test of the insulation monitoring device 1 includes at least an alarm activation test, an accuracy test, and an Ior accuracy test. The alarm activation test is a test to confirm that the insulation monitoring device 1 enters an alarm state by outputting a test current It that is equal to or greater than the alarm threshold Th. The accuracy test is a test to confirm the measurement accuracy of the leakage current detection unit 13 by outputting a test current It of a predetermined current value and comparing the measurement result of the insulation monitoring device 1 with the measurement result of the current flowing through the test current output line 5 by a calibrated portable measurement terminal 4. The Ior accuracy test confirms the measurement accuracy of the Ior measurement method of the insulation monitoring device 1 and includes an Ior current value accuracy test to confirm the measurement accuracy of the leakage current detection unit 13 and an Ior phase difference accuracy test to confirm the accuracy of the leakage current detection unit 13 and the phase difference calculation unit 21, which will be described later.

[0023] The test current output unit 15 has the function of outputting a dummy leakage current synchronized with the reference voltage Vref (same frequency and same phase) when the operation test is performed. The test current output unit 15 is electrically connected to the test current output line 5 through which the zero-phase current transformer 12 passes, and when the operation test selection unit 14 turns it ON, it starts outputting a test current It as a dummy leakage current to the test current output line 5, with a predetermined current value (effective value), the same frequency as the reference frequency, and the same phase as the reference frequency. The predetermined current value of the test current It can be set and stored in advance in the insulation monitoring device 1 before the operation test. Hereinafter, the predetermined current value (effective value) set for the test current It will be referred to as the set test current value RMS(It). In this embodiment, the set test current value RMS(It) is selected so that the alarm operation test and the accuracy test can be performed with the same test current It.

[0024] Specifically, after the operator turns on the operation test selection unit 14, and the leakage current detection unit 13 acquires the first measured leakage current Iom(1), the test current output unit 15 outputs the test current It to the test current output line 5. The set test current value RMS(It) of the test current It is set to a value suitable for alarm operation tests and accuracy tests, for example, based on the evaluation standard "50mA" which is based on the laws and regulations for electrical safety work. In addition, the test current output unit 15 stops outputting the test current It when the operator turns off the operation test selection unit 14. The current value of the test current It output by the test current output unit 15 can be changed or set on the front panel of the insulation monitoring device 1, and the performance of outputting the set current value and phase is calibrated at the time of shipment or by periodic calibration.

[0025] A portion of the wiring of the test current output line 5 is provided to be physically accessible from the front panel of the insulation monitoring device 1. At least during the execution of the operational test, the operator clamps the wiring of the test current output line 5 with the portable measuring terminal 4. In this state, the portable measuring terminal 4 detects the terminal measurement current Ih, which is the current value (effective value) of the test current It flowing through the test current output line 5, and acquires and stores the detection result of the terminal measurement current Ih as one of the terminal measurement information.

[0026] The arithmetic control unit 16 is an arithmetic control unit composed of a computer 500, which will be described later. It is connected to each component and detection unit inside the insulation monitoring device 1 via wired or wireless communication to acquire information, perform various calculations, and control the connected units. The arithmetic control unit 16 can also communicate with external devices, such as a portable measurement terminal 4, to acquire terminal measurement information. In this embodiment, the arithmetic control unit 16 mainly operates according to a predetermined operation test program that is pre-installed, and generates information regarding the detection accuracy of the leakage current detection unit 13. Specifically, it has the function of executing operation test routines and other support programs that control the acquisition of information necessary for operation testing, perform calculations based on the acquired information, make judgments for alarm operation tests and accuracy tests using the calculation results, and control the display and alarm output based on the judgment results. The arithmetic control unit 16 may be composed of multiple units, in which case each unit may work together to perform its functions. Details of the arithmetic control unit 16 will be described later.

[0027] The display unit 17 is, for example, a liquid crystal panel display (LCD) and is provided, for example, on the front panel of the insulation monitoring device 1. As shown in Figure 3, the display unit 17 switches between displayed items, values, and units by pressing the up and down buttons B1 and B2 located near the display area D. The display unit 17 has the function of displaying at least the leakage current Io (upper part of Figure 3), the phase difference θ(Io) of the leakage current Io (middle part of Figure 3), and the resistive component leakage current Ior of the leakage current Io (lower part of Figure 3) as measurement results of the insulation monitoring device 1. In addition, during the execution of the operation test, the word "TEST" is displayed in the display area D. In addition, during the execution of the operation test, the leakage current change ΔIo (described later) is displayed as the leakage current Io, the phase difference (Angle) is displayed as the change phase difference θ(ΔIo), and the resistive component leakage current Ior is displayed as the reference phase parallel component ΔIo(x).

[0028] The alarm output unit 18, when the calculation control unit 16 determines that the measured leakage current Iom is equal to or greater than the alarm threshold Th, activates an indicator lamp, buzzer, LCD display, or a combination thereof, on the front panel of the insulation monitoring device 1 to provide a leakage current alarm. The alarm output unit 18 also generates a leakage current alarm signal and outputs it externally. The alarm threshold Th is set to, for example, "50mA".

[0029] <Configuration and Functions of the Arithmetic Control Unit> Next, the internal configuration and functions of the arithmetic control unit 16 will be explained with reference to Figure 4. Figure 4 is a block diagram showing the configuration of the arithmetic control unit 16 and the input / output configuration of the operational test performed by the arithmetic control unit 16.

[0030] In this embodiment, the calculation control unit 16 mainly uses the reference voltage Vref detected by the reference voltage detection unit 11 and the measured leakage current Iom detected by the leakage current detection unit 13 to perform various calculations and comparison judgments with predetermined thresholds to generate information regarding the detection accuracy of the leakage current of the insulation monitoring device 1. The calculation control unit 16 also has the function of displaying or outputting information regarding the detection accuracy of the leakage current of the insulation monitoring device 1, such as measurement results, calculation results, judgment results, and alarms, by controlling the display unit 17 and the alarm output unit 18, etc. The calculation control unit 16 also has the function of controlling the test current output unit 15 in response to the on / off operation of the operation test selection unit 14. The calculation control unit 16 includes a phase difference calculation unit 21, a vector calculation unit 22, a judgment unit 23, a resistance component leakage current calculation unit 24, and a control unit 25.

[0031] The phase difference calculation unit 21 detects the phase difference θ(Iom) of the measured leakage current Iom with respect to the reference phase, based on the RMS(Iom) of the measured leakage current Iom detected by the leakage current detection unit 13 and the RMS(Vref) of the reference voltage Vref detected by the reference voltage detection unit 11. Specifically, the phase difference calculation unit 21 detects the phase difference θ(Iom) of the measured leakage current Iom with respect to the reference phase, based on the time difference between the point where the reference voltage Vref crosses zero and the point where the measured leakage current Iom crosses zero, with respect to the time of one period of the reference frequency F(Vref) calculated by the reference voltage detection unit 11. For simplicity, in the following explanation, the phase difference θ(Iom) is calculated assuming the reference phase is 0°. The phase difference calculation unit 21 calculates the first measured phase difference θ(Iom(1)) of the first measured leakage current Iom(1) and the second measured phase difference θ(Iom(2)) of the second measured leakage current Iom(2) during the execution of the operational test.

[0032] During the execution of the operational test, the vector calculation unit 22 performs vector calculations based on the first measured leakage current Iom(1) and the second measured leakage current Iom(2) to calculate the leakage current change ΔIo and the orthogonal components of the leakage current change ΔIo.

[0033] Specifically, the vector of the leakage current change ΔIo is calculated by subtracting the vector of the first measured leakage current Iom(1), whose magnitude and direction (angle) are defined by the RMS(Iom(1)) of the first measured leakage current Iom(1) and the first measured phase difference θ(Iom(1)), from the vector of the second measured leakage current Iom(2), whose magnitude and direction (angle) are defined by the RMS(Iom(2)) of the second measured leakage current Iom(2) and the second measured phase difference θ(Iom(2)), using equation (1) below. Details of the vector calculation will be described later. ΔIo=Iom(2)-Iom(1) (Equation 1)

[0034] The vector of the leakage current change ΔIo is defined by its magnitude as the change current value RMS(ΔIo) and its direction (angle) as the change phase difference θ(ΔIo). That is, the change current value RMS(ΔIo) is the effective value of the current value of the leakage current change ΔIo, and the change phase difference θ(ΔIo) is the phase difference of the leakage current change ΔIo with respect to the reference phase. In the following explanation, the leakage current change ΔIo will be denoted as ΔIo(2-1), and multiple sets of first measured leakage currents Iom(1) and second measured leakage currents Iom(2) acquired at different timings may be distinguished.

[0035] Furthermore, the vector calculation unit 22 calculates the current value RMS(ΔIo(x)) of the reference phase parallel component ΔIo(x), which is in phase with the reference phase (i.e., parallel to the vector of the test current It), and the current value RMS(ΔIo(y)) of the reference phase perpendicular component ΔIo(y), which is perpendicular to the reference phase (i.e., perpendicular to the vector of the test current It), as orthogonal components of the leakage current change ΔIo, based on the change current value RMS(ΔIo) and the change phase difference θ(ΔIo).

[0036] During the execution of the operational test, the determination unit 23 determines whether the change in current value RMS(ΔIo) is equal to or greater than the alarm threshold Th as an alarm activation test (alarm activation determination).

[0037] Furthermore, during the execution of the operational test, the determination unit 23 determines, as an accuracy test, whether the difference between the current value RMS(ΔIo) of the leakage current change ΔIo and the terminal measurement current Ih obtained from the portable measurement terminal 4 is outside a predetermined error range (accuracy determination). The predetermined error range is set, for example, to ±10% of the terminal measurement current Ih. Note that the setting value of the predetermined error range can be changed in the insulation monitoring device 1.

[0038] Furthermore, during the execution of the operational test, the determination unit 23 makes a determination on the following two conditions as an accuracy test of the Ior measurement method (Ior accuracy determination). (Condition 1) Whether the difference between the current value of the reference phase-parallel component ΔIo(x) and the terminal measurement current Ih obtained from the portable measurement terminal 4 is outside the range of a predetermined error (Ior current value accuracy determination). (Condition 2) Whether the change in phase difference θ (ΔIo) is outside the range of a predetermined error with respect to the reference phase (0°) (Ior phase difference accuracy determination) If condition 1 is true, the detection accuracy of the current value in the Ior measurement method of the insulation monitoring device 1 is inaccurate. If condition 2 is true, the detection accuracy of the phase difference in the Ior measurement method of the insulation monitoring device 1 is inaccurate. The predetermined error ranges are set to, for example, ±10% of the terminal measurement current Ih and ±5 degrees of the reference phase. Note that the setting values ​​of the predetermined error ranges can be changed in the insulation monitoring device 1.

[0039] The resistive component leakage current calculation unit 24 calculates the resistive component leakage current Ior included in the leakage current Io flowing through the power line 6 under test, based on the effective value of the leakage current Io detected by the leakage current detection unit 13 and the phase difference θ(ΔIo) detected by the phase difference calculation unit 21. In this embodiment, when the operation test is not being performed, the resistive component leakage current calculation unit 24 displays the calculation result of the resistive component leakage current Ior on the display unit 17.

[0040] The control unit 25 has functions for communication and data input / output between the calculation control unit 16 and external devices, as well as internal control of the calculation control unit 16. The control unit 25 communicates with the portable measurement terminal 4 and acquires the terminal measurement current Ih.

[0041] <Vector operations> Next, specific examples of vector operations in this embodiment will be described for each connection method.

[0042] First, we will explain the case of a single-phase three-wire system shown in Figure 2(a), referring to Figures 2 and 5 through 8. Figure 5 is a diagram showing the vector of the generated leakage current that occurs in the power line 6 under test when the test current It is not output in a single-phase three-wire system. Figure 6 shows (a) the vector of the generated leakage current that occurs in the power line 6 under test, and (b) the vector of the accurately detected measured leakage current, when the test current It is output in a single-phase three-wire system. Figure 7 shows (a) the vector of the generated leakage current and the inaccurately detected measured leakage current that occur in the power line 6 under test, and (b) the vector of the leakage current change component of the inaccurately detected measured leakage current, when the test current It is output in a single-phase three-wire system. Figure 8 is a diagram showing the leakage current change component vector of Figure 7(b) decomposed into orthogonal components.

[0043] In the case of a single-phase three-wire system, as shown in Figure 2(a), it consists of phase A and phase B relative to the intermediate line N. In this embodiment, the reference voltage detection unit 11 is electrically connected to the intermediate line N and phase A to detect the reference voltage Vref. Alternatively, the reference voltage Vref may be detected between the intermediate line N and phase B. The xy plane in Figures 5 and 6 is a plane that shows the current value (effective value) as a vector based on the magnitude (effective value) RMS(Io) and phase difference θ(Io) of the leakage current Io generated in the power line 6 under test, with the phase of the reference voltage Vref (reference phase) set to 0°, and the phase difference with respect to the reference phase expressed in the direction of 0° to 360°.

[0044] In the case of a single-phase three-wire system, the x-axis shows the ground fault component (resistive component) of phase A, where the reference voltage Vref is detected, to the right of the central intersection point O, and the ground fault component (resistive component) of phase B to the left. The y-axis shows the capacitance component of phase A, which occurs 90° ahead of the ground fault component (resistive component) of phase A, to the upper part of the intersection point O, and the capacitance component of phase B, which occurs 90° ahead of the resistance component (resistive component) of phase B, to the lower part of the intersection point O. Here, the four quadrants separated by the y-axis and x-axis of the xy-plane are called quadrant α (upper right), quadrant β (upper left), quadrant γ (lower left), and quadrant δ (lower right), as shown in Figures 5 to 8.

[0045] Next, we will explain the vector calculation for the case where the first generated leakage current Ioa(1) actually occurring in the circuit 3 (the power line 6 under measurement) when the test current It is not being output occurs in quadrant α, for example, as shown in Figure 5. In this case, if the accuracy of the leakage current detection unit 13 is correct, the leakage current detection unit 13 will detect and acquire a first measured leakage current Iom(1) that is the same magnitude and direction as the first generated leakage current Ioa(1).

[0046] As shown in Figure 6(a), when a test current It, which is in phase with the reference phase, is output, a vector of the test current It is generated in the power line 6 under test. Since the first generated leakage current Ioa(1) is generated in the power line 6 under test without changing before and after the output of the test current It, when the test current It is output, a second generated leakage current Ioa(2), which is the vector sum of the first generated leakage current Ioa(1) and the test current It, is generated in quadrant α. At this time, if the accuracy of the leakage current detection unit 13 is correct, the leakage current detection unit 13 will acquire a second measured leakage current Iom(2) which has the same magnitude and phase as the second generated leakage current Ioa(2).

[0047] Then, in the arithmetic control unit 16, as shown in Figure 6(b), the leakage current change ΔIo(2-1), which is the vector difference between the second measured leakage current Iom(2) and the first measured leakage current Iom(1), is calculated.

[0048] If the leakage current detection unit 13 is accurate, the calculated leakage current change ΔIo(2-1) is a vector having the same scalar quantity and direction as the test current It. That is, the current value (magnitude) of the leakage current change ΔIo is the set test current value RMS(It) of the test current It, and its phase is in phase with the reference phase. Therefore, during the execution of the operational test, by comparing the leakage current change ΔIo(2-1) with the alarm threshold Th to determine whether the alarm is activated, the alarm activation test can be performed without removing the zero-phase current transformer 12 from the circuit 3.

[0049] On the other hand, if the leakage current detection unit 13 inaccurately detects the leakage current Io due to a decrease in the measurement accuracy of the leakage current detection unit 13, for example, as shown in Figure 7(a), the leakage current detection unit 13 will detect a first measured leakage current Iom(1') and a second measured leakage current Iom(2') that deviate from the first generated leakage current Ioa(1) and the second generated leakage current Ioa(2) that are actually occurring. In Figure 7(a), the first measured leakage current is denoted as Iom(1') and the second measured leakage current as Iom(2') in order to distinguish between the accurately detected measured leakage current Iom and the inaccurately detected measured leakage current Iom.

[0050] At this time, as shown in Figure 7(b), the leakage current change ΔIo(2'-1'), which is the vector difference between the second measured leakage current Iom(2') and the first measured leakage current Iom(1'), differs from the test current It in either magnitude and direction or both.

[0051] Therefore, if the magnitude of the leakage current change ΔIo, calculated based on the first measured leakage current Iom(1) detected by the leakage current detection unit 13 when the test current It is not output during the execution of the operational test, and the second measured leakage current Iom(2) detected by the leakage current detection unit 13 when the test current It is output, differs from the magnitude of the test current It, then it can be said that the detection accuracy of the leakage current detection unit 13 is not accurate. Similarly, if the direction of the leakage current change ΔIo differs from the direction of the test current It, then it can be said that the detection accuracy or calculation accuracy of either or both the leakage current detection unit 13 and the phase difference calculation unit 21 is not accurate.

[0052] Furthermore, as shown in Figure 8, when the leakage current change ΔIo(2'-1') is decomposed into orthogonal components parallel to the x and y axes of the xy-plane, the vector of the component parallel to the x axis is defined as the reference phase parallel component ΔIo(x), and its magnitude is defined as RMS(ΔIo(x)). The vector of the component parallel to the y axis is defined as the reference phase perpendicular component ΔIo(y), and its magnitude is defined as RMS(ΔIo(y)). Since the test current It is parallel to the x axis and perpendicular to the y axis, the reference phase parallel component ΔIo(x) is parallel to the test current It, and the reference phase perpendicular component ΔIo(y) is perpendicular to the test current It. Furthermore, the magnitude of the reference phase parallel component ΔIo(x) RMS(ΔIo(x)) and the magnitude of the reference phase perpendicular component ΔIo(y) RMS(ΔIo(y)) are calculated using the change in current value RMS(ΔIo) and the change in phase difference θ(ΔIo) by equations (2) and (3) below, respectively. RMS(ΔIo(x))=RMS(ΔIo)*|cos(θ(ΔIo))| (Formula 2) RMS(ΔIo(y))=RMS(ΔIo)*|sin(θ(ΔIo))| (Formula 3)

[0053] In the case of a single-phase three-wire system, the component parallel to the x-axis represents the resistive component of the leakage current. Therefore, the calculated reference phase-parallel component ΔIo(x) corresponds to the resistive component of the A-phase or B-phase of the leakage current change ΔIo, i.e., the resistive component leakage current Ior. Consequently, during the execution of the operational test, the value of the reference phase-parallel component ΔIo(x) is displayed on the display unit 17 as the resistive component leakage current Ior.

[0054] Next, we will explain the case of a three-phase three-wire delta connection with reference to Figure 9. Figure 9 shows (a) the vector of the leakage current generated in the measured power line 6 when the test current It is not output, (b) the leakage current generated in the measured power line 6 when the test current It is output, and (c) the vector of the measured leakage current and the projected current change detected when the test current It is output.

[0055] In the case of a three-phase three-wire delta connection, as shown in Figure 2(b), it consists of three phases: S phase, T phase, and R phase with respect to the S phase ground. In this embodiment, the reference voltage detection unit 11 is electrically connected to the R phase and T phase to detect the reference voltage Vref. Each xy plane in Figure 9 is a plane that shows the leakage current Io generated in the power line 6 under test as a vector, with the current value (effective value) represented by the length of the arrow (magnitude, scalar quantity) and the phase difference with respect to the reference phase represented in the range of 0° to 360°, when the phase of the reference voltage Vref (reference phase) is 0°. As shown in Figure 9(a), the vector of the reference voltage Vref obtained in the R phase-T phase is parallel to the x axis, and the reference phase is 0°. Similar to the single-phase three-wire case, the upper right is called quadrant α, the upper left is called quadrant β, the lower left is called quadrant γ, and the lower right is called quadrant δ.

[0056] The vector calculation will now be explained for the case where the first generated leakage current Ioa(1) actually occurring in the circuit 3 (the power line 6 under measurement) when the test current It is not being output occurs in quadrant β, for example, as shown in Figure 9(a). In this case, if the accuracy of the leakage current detection unit 13 is correct, the leakage current detection unit 13 will detect and acquire a first measured leakage current Iom(1) that is the same magnitude and direction as the first generated leakage current Ioa(1).

[0057] As shown in Figure 9(b), when a test current It that is in phase with the reference phase is output, a vector of the test current It is generated in the power line 6 under test. Since the first generated leakage current Ioa(1) is generated in the power line 6 under test without changing before and after the output of the test current It, when the test current It is output, a second generated leakage current Ioa(2), which is the vector sum of the first generated leakage current Ioa(1) and the test current It, is generated in quadrant α or β. At this time, if the accuracy of the leakage current detection unit 13 is accurate, as shown in Figure 9(c), the leakage current detection unit 13 acquires a second measured leakage current Iom(2) that is the same magnitude and direction as the second generated leakage current Ioa(2).

[0058] Then, the arithmetic control unit 16 calculates the leakage current change ΔIo, which is the vector difference between the second measured leakage current Iom(2) and the first measured leakage current Iom(1). The case where the accuracy of the leakage current detection unit 13 is inaccurate, and the calculation of the orthogonal components, are the same as for the single-phase three-wire system, so the explanation is omitted.

[0059] Next, we will explain the case of a three-phase three-wire star connection with reference to Figure 10. Figure 10 shows the following in a three-phase three-wire (star connection): (a) a diagram showing the vector of leakage current generated in the measured power line 6 when no test current is output, (b) a diagram showing the leakage current generated in the measured power line 6 when a test current is output, and (c) a diagram showing the measured leakage current and the vector of the change in leakage current detected when a test current is output.

[0060] In the case of a three-phase three-wire star connection, as shown in Figure 2(c), it consists of three phases: S phase, T phase, and R phase with respect to the neutral point grounding. In this embodiment, the reference voltage detection unit 11 is electrically connected to the R phase and T phase to detect the reference voltage Vref. Each xy plane in Figure 10 is a plane that shows the leakage current Io generated in the power line 6 under test as a vector, with the current value (effective value) represented by the length of the arrow (magnitude, scalar quantity) and the phase difference with respect to the reference phase represented in the range of 0° to 360°, when the phase of the reference voltage Vref (reference phase) is 0°. As shown in Figure 10(a), the vector of the reference voltage Vref obtained between the R phase and T phase is parallel to the x axis, and the reference phase is 0°. Similar to the single-phase three-wire case, the upper right is called quadrant α, the upper left is called quadrant β, the lower left is called quadrant γ, and the lower right is called quadrant δ.

[0061] The vector calculation will now be explained for the case where the first generated leakage current Ioa(1) actually occurring in the circuit 3 (the power line 6 under measurement) when the test current It is not being output occurs in quadrant δ, for example, as shown in Figure 10(a). In this case, if the accuracy of the leakage current detection unit 13 is correct, the leakage current detection unit 13 will detect and acquire a first measured leakage current Iom(1) that is the same magnitude and direction as the first generated leakage current Ioa(1).

[0062] As shown in Figure 10(b), when a test current It that is in phase with the reference phase is output, a vector of the test current It is generated in the power line 6 under test. Since the first generated leakage current Ioa(1) is generated in the power line 6 under test without changing before and after the output of the test current It, when the test current It is output, a second generated leakage current Ioa(2), which is the vector sum of the first generated leakage current Ioa(1) and the test current It, is generated in quadrant δ. At this time, if the accuracy of the leakage current detection unit 13 is accurate, as shown in Figure 10(c), the leakage current detection unit 13 acquires a second measured leakage current Iom(2) that is the same magnitude and direction as the second generated leakage current Ioa(2).

[0063] Then, the arithmetic control unit 16 calculates the leakage current change ΔIo, which is the vector difference between the second measured leakage current Iom(2) and the first measured leakage current Iom(1). The case where the accuracy of the leakage current detection unit 13 is inaccurate, and the calculation of the orthogonal components, are the same as for the single-phase three-wire system, so the explanation is omitted.

[0064] As described above, in each wiring method, the leakage current change ΔIo, the reference phase parallel component ΔIo(x) and the reference phase perpendicular component ΔIo(y), which are orthogonal components of the leakage current change ΔIo, can be calculated by vector calculation.

[0065] <Operation Test Method> Figure 11 is a flowchart relating to the operation test routine of the insulation monitoring device in this embodiment. The following explanation will follow this flowchart. The operation test routine starts when the operation test selection unit 14 is turned ON.

[0066] First, in step S1, the reference voltage detection unit 11 acquires the reference voltage Vref of the circuit 3. Also, the leakage current detection unit 13 acquires the first measured leakage current Iom(1) of the power line 6 under test when the test current It is not outputting.

[0067] In step S2, the test current output unit 15 outputs a test current It to the test current output line 5, which has a magnitude equal to the set test current value RMS(It) and is in phase with the reference phase. The calculation control unit 16 also displays the set test current value RMS(It) on the display unit 17.

[0068] In the subsequent step S3, the leakage current detection unit 13 acquires the second measured leakage current Iom(2) of the power line 6 under test while the test current It is output from the test current output unit 15.

[0069] In the subsequent step S4, the calculation control unit 16 obtains the terminal measurement current Ih from the portable measurement terminal 4 via the control unit 25.

[0070] In step S5, the vector calculation unit 22 performs a vector calculation based on the first measured leakage current Iom(1) and the second measured leakage current Iom(2) to calculate the leakage current change ΔIo, the change current value RMS(ΔIo), and the change phase difference θ(ΔIo). Furthermore, the vector calculation unit 22 calculates the reference phase parallel component ΔIo(x) and the reference phase perpendicular component ΔIo(y), which are orthogonal components of the leakage current change ΔIo.

[0071] In the subsequent step S6, the calculation control unit 16 displays the change in current value RMS(ΔIo), the change in phase difference θ(ΔIo), and the reference phase parallel component ΔIo(x) on the display unit 17.

[0072] In step S7, the determination unit 23 performs an alarm activation determination. If the determination result is true (Yes), the process proceeds to step S8. On the other hand, if the determination result is false (No), the process proceeds to step S9.

[0073] In step S8, if the alarm activation determination in step S7 is determined to be true (Yes), the calculation control unit 16 generates and outputs a leakage current detection alarm in the alarm output unit 18, and proceeds to step S9.

[0074] In step S9, that is, if the alarm activation determination in step S7 is determined to be false (No), or if the operation in step S8 is completed by resetting the alarm, the determination unit 23 performs accuracy determination, I or current value accuracy determination, and I or phase difference accuracy determination. If any of these determination results are true (Yes), the process proceeds to step S10. On the other hand, if all of these determination results are false (No), the process proceeds to step S11.

[0075] In step S10, if any of the accuracy determination, I or current value determination, or I or phase difference determination in step S9 is determined to be true (Yes), then, at the request of the calculation control unit 16, the alarm output unit 18 generates and outputs an accuracy abnormality alarm for the leakage current detection unit 13, and the process proceeds to step S11.

[0076] In step S11, if all of the accuracy determination, Ior current value determination, and Ior phase difference determination in step S9 are determined to be false (No), or if the operation in step S10 is completed by an alarm reset or the like, the calculation control unit 16 receives a release request due to the off operation of the operation test selection unit 14, stops the output of the test current It in the test current output unit 15, and returns the routine.

[0077] <Operation Test Program> The operation test program for the insulation monitoring device 1, which performs an operation test of the insulation monitoring device 1 without removing the zero-phase current transformer 12 of the insulation monitoring device 1 from the circuit 3, mainly consists of the following steps and is executed by the computer 500 (hardware).

[0078] Step 1 (Reference Voltage Detection Step): A step to detect the voltage applied between any two phases of the circuit 3 and obtain it as the reference voltage Vref. Step 2 (First measured leakage current acquisition step): A step in which the leakage current flowing through circuit 3 is detected and acquired as the first measured leakage current Iom(1). Step 3 (Test Current Output Step): A step in which a test current It of a predetermined magnitude and synchronized with the reference voltage Vref (i.e., having the same frequency and phase as the reference voltage Vref) is output to the test current output line 5. Step 4 (Second Measurement Leakage Current Acquisition Step): This step involves detecting the leakage current flowing through the circuit 3 and the test current output line 5 (the power line under measurement 6) when the test current It is output to the test current output line 5, and acquiring it as the second measurement leakage current Iom(2). Step 5 (Calculation Step): A step to generate information regarding the detection accuracy of the leakage current detection unit 13 based on the first measured leakage current Iom(1) and the second measured leakage current Iom(2).

[0079] Here, the configuration and operation of computer 500 will be explained using diagrams. Figure 14 is a block diagram showing the configuration of computer 500. Figure 15 is a block diagram showing the hardware configuration.

[0080] As shown in Figure 14, the computer 500 is configured with a processor 501, memory 502, storage 503, input / output I / F 504, and communication I / F 505 connected on bus A, and the functions and / or methods described herein are realized through the cooperation of these components.

[0081] The I / F 504 can be connected to, for example, a display that shows various information and a touch panel that accepts user input. The touch panel is positioned in front of the display. Therefore, the user can perform intuitive operations by touching icons displayed on the display with their finger. Note that the touch panel does not have to be positioned in front of the display. Alternatively, a pointing device such as a keyboard and mouse may be connected to the I / F 504 instead of, or in conjunction with, the touch panel. Furthermore, a speaker that outputs sound externally and a microphone that receives external sound may also be connected to the I / F 504.

[0082] The display is composed of a liquid crystal display or an organic EL (Electro-Luminescence) display, and under the control of the processor 501, it displays various information, thereby realizing some of the functions of the display unit 17. The processor 501 controls the display based on a support program, thereby realizing some of the functions of the display unit 17.

[0083] Memory 502 consists of RAM (Random Access Memory). RAM is composed of either volatile or non-volatile memory.

[0084] The storage 503 consists of ROM (Read Only Memory). ROM is composed of non-volatile memory and is implemented, for example, by an HDD (Hard Disk Drive) or SSD (Solid State Drive). The storage 503 stores various programs, such as the operational test programs implemented in steps 1 to 5 described above.

[0085] For example, the processor 501 controls the operation of the entire computer 500. The processor 501 is an arithmetic unit that loads the operating system and various programs that realize diverse functions from the storage 503 into the memory 502 and executes the instructions contained in the loaded programs.

[0086] Specifically, when the processor 501 receives a user input, it reads a program (for example, an operation test program) stored in the storage 503, loads the read program into the memory 502, and executes the program. Furthermore, the execution of the operation test program by the processor 501 enables the various functions of the arithmetic control unit 16.

[0087] The configuration of the processor 501 will now be described. The processor 501 can be implemented, for example, by a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), various other processing units, or a combination thereof.

[0088] Furthermore, in order to implement the functions and / or methods described herein, some or all of the functions such as the processor 501, memory 502, and storage 503 may be configured as a dedicated hardware processing circuit 601, as shown in Figure 15. The processing circuit 601 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0089] Furthermore, although the processor 501 has been described as a single component, it is not limited to this and may be composed of a collection of multiple physically separate processors. In this specification, a program or instructions contained in such a program described as being executed by the processor 501 may be executed by a single processor 501 or may be executed in a distributed manner by multiple processors. Also, a program or instructions contained in such a program executed by the processor 501 may be executed by multiple virtual processors.

[0090] The communication I / F505 is an interface that conforms to a specified communication standard and communicates with external devices via wired or wireless connection.

[0091] In this way, the operation test program for the insulation monitoring device 1 is executed by the computer 500, which allows the operation test of the insulation monitoring device 1 to be performed without removing the zero-phase current transformer 12 of the insulation monitoring device 1 from the circuit 3.

[0092] As described above, in the insulation monitoring device 1 of this embodiment, the operation test is performed while the circuit 3 remains live. The calculation control unit 16 acquires the first measured leakage current Iom(1) detected by the leakage current detection unit 13 when the test current It is not output, and the second measured leakage current Iom(2) detected by the leakage current detection unit 13 when the test current It is output, and calculates the leakage current change ΔIo by performing a vector difference between these two values. The insulation monitoring device 1 then considers the calculated leakage current change ΔIo as the test current It detected by the leakage current detection unit 13 and performs alarm activation and accuracy determination for the operation test. Therefore, it is not necessary to remove the zero-phase current transformer 12 from the circuit 3, and the operation test can be performed safely. In addition, since it is not necessary to shut off the circuit 3, the burden on users of the circuit 3 is reduced. Furthermore, since the output of the test current It is completed in a few seconds, the operation test can be performed in a short time, and the operation test is less susceptible to fluctuations in the leakage current situation of the circuit 3.

[0093] Furthermore, the determination unit 23 performs alarm operation determination and accuracy determination based on the leakage current change ΔIo. Here, theoretically, the leakage current change ΔIo is a vector with the same magnitude (scalar quantity) and direction (phase difference) as the test current It, and is essentially identical. Therefore, as long as the set test current value RMS(It) of the test current It is greater than or equal to the alarm threshold Th, operation tests and accuracy tests can be performed by setting an arbitrary and known current value. In this way, by being able to set a known current value for the test current It, the output configuration of the test current It can be simplified, and the output of the test current It is completed in a few seconds, enabling operation tests in a short time, and thus allowing for more accurate operation tests without being affected by changes in the leakage current situation of the circuit 3. In addition, the current value of the test current It can be set without using the current value acquired by the leakage current detection unit 13. Therefore, the detection accuracy of the leakage current detection unit 13 can be diagnosed more accurately. Furthermore, even if, for example, before outputting the test current It (when no output is performed), a leakage current Io exceeding the alarm threshold Th is already flowing through the circuit 3 and the insulation monitoring device 1 would trigger an alarm, the device 1 will still output a predetermined test current It and use the leakage current change ΔIo, which is the change before and after the test current output, to perform alarm operation determination and accuracy determination. In other words, operation tests and accuracy tests can be performed regardless of the state of the circuit 3 before the operation test, specifically before the test current output.

[0094] Furthermore, the calibration-enabled portable measuring terminal 4 detects the test current It, and the terminal measurement current Ih is acquired. By comparing this with the calculated leakage current change ΔIo, the accuracy of the detection result of the leakage current detection unit 13 is automatically determined. This allows for quicker and more efficient detection of accuracy abnormalities by the operator or remotely. In addition, since no external equipment other than the portable measuring terminal 4 is required, operational testing can be performed with a simple configuration.

[0095] Furthermore, by comparing the calculated leakage current change ΔIo with the set test current value RMS(It), the accuracy of the detection result of the leakage current detection unit 13 is automatically determined. This allows for the performance testing, including accuracy testing, to be performed easily and quickly with a simpler configuration using the device alone.

[0096] Furthermore, by calculating the phase difference θ(ΔIo), the reference phase parallel component ΔIo(x), which is a vector component parallel to the test current It, and the reference phase perpendicular component ΔIo(y), which is a vector component perpendicular to the leakage current change ΔIo, it becomes possible to verify and diagnose the detection accuracy of the leakage current detection unit 13 and the detection accuracy of the phase difference calculation unit 21, which are necessary for the calculation of the Ior measurement method.

[0097] Furthermore, by displaying the results of the vector calculation on the display unit 17, operators can easily compare them with the measurement results from the portable measurement terminal 4, thereby improving work efficiency. In addition, by outputting an alarm based on the accuracy judgment results, accuracy abnormalities can be more efficiently identified by operators or remotely.

[0098] Based on the above, the insulation monitoring device 1 according to this embodiment can perform operational tests and accuracy tests of the insulation monitoring device 1 safely and accurately in a short time with a simple configuration.

[0099] Although embodiments of the present invention have been described above, these embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0100] For example, in the above embodiment, the circuit 3 was a single-phase three-wire or three-phase three-wire system, but the circuit 3 may also be a single-phase two-wire system or a three-phase four-wire system (star connection).

[0101] Furthermore, in the above embodiment, the reference voltage detection unit 11 was electrically connected to any two of the three phases of the circuit 3, but it may also be connected to all three phases of the circuit 3 and detect the voltage applied between any two of those phases.

[0102] Furthermore, in the above embodiment, the zero-phase current transformer 12 passed through the entire circuit 3, but instead of passing through the entire three-phase, three-wire circuit 3, it may also pass through only the low-voltage Class B grounding wire G. This allows the use of a less expensive ZCT with a smaller diameter.

[0103] In the above embodiment, the operation in which the arithmetic control unit 16 acquires the terminal measurement current Ih from the portable measurement terminal 4 via the control unit 25 was performed in step S4, but it is sufficient if it is performed after the output of the test current It in step S2 and before the accuracy determination in step S9.

[0104] Furthermore, in the above embodiment, the RMS(Ih) current value of the terminal measurement current Ih was used to calculate the difference in the accuracy determination and Ior current value accuracy determination performed by the determination unit 23. However, instead, the set test current value RMS(It), which is the output value of the test current It stored inside the insulation monitoring device 1, may be used to calculate the difference. This makes it possible to supplementarily diagnose the detection accuracy of the leakage current detection unit 13 based on the reliability of the calibration at the time of shipment or periodic calibration of the insulation monitoring device 1, without using the portable measurement terminal 4.

[0105] Furthermore, in the above embodiment, the determination unit 23 determined whether the change in phase difference θ (ΔIo) was outside a predetermined error range with respect to the reference phase (0°). However, instead, the detection accuracy of the phase difference may be determined using the reference phase perpendicular component ΔIo(y).

[0106] Furthermore, in the above embodiment, the display unit 17 only displayed numerical values ​​as shown in Figure 3, but the display unit 17 may also be provided with an additional display area to display vector diagrams as shown in Figures 5 to 10. This allows the operator to visually understand the information.

[0107] The test current output unit 15 may have a predetermined phase of the test current It that can be set or stored in the insulation monitoring device 1 before the operation test. Furthermore, the test current output unit 15 may have its output phase of the test current It changed or set via the front panel of the insulation monitoring device 1, and its ability to output the set phase may be calibrated at the time of shipment or through periodic calibration. This allows for simple adjustment (temporary calibration) of the test current output unit 15 if the test current output does not synchronize well with the reference voltage phase.

[0108] For example, in the above embodiment, the portable measurement terminal 4 only had the function of detecting the current of the test current output line 5. However, as shown in the first modified example in Figure 12, it may also be a terminal that has the function of electrically connecting to any two of the three phases of the circuit 3 to acquire the terminal measurement voltage Vh, and can calculate, display, and output the terminal measurement resistance component current Iorh, which is the resistance component of the terminal measurement current Ih detected based on the terminal measurement voltage Vh. Then, as shown in the operation test flow of the first modified example in Figure 13, the calculation control unit 16 of the insulation monitoring device 1 acquires the terminal measurement current Ih, terminal measurement voltage Vh, and terminal measurement resistance component current Iorh from the portable measurement terminal 4 as terminal measurement information. In the accuracy determination in step S9, it further calculates the difference between the reference phase parallel component ΔIo(x) and the terminal measurement resistance component current Iorh, and determines whether the difference is outside a predetermined error range. If it is determined to be outside the range, in step S10 a separate alarm may be generated and output as the measurement error of the resistance component leakage current Ior. This allows for a more accurate determination of the measurement error of the insulation monitoring device 1 using the Ior method. [Explanation of symbols]

[0109] 1: Insulation monitoring device 2: Transformer 3:Cable line (monitored line) 4: Portable measuring device 5: Test current output line 6: Electrical line under test 11: Reference voltage detection unit 12:Zero phase current transformer 13: Leakage current detection unit 14: Operation Test Selection Section 15: Test current output section 16: Calculation Control Unit (Calculation Section) 17:Display section 18: Alarm output section 21: Phase difference calculation section 22: Vector Calculation Unit 23: Judgment section 24: Resistive component leakage current calculation unit 25: Control Unit

Claims

1. A reference voltage detection unit that detects the voltage applied between any two phases of the monitored AC circuit and acquires it as a reference voltage, A test current output unit capable of outputting a test current synchronized with the aforementioned reference voltage to a test current output line, A leakage current detection unit that acquires the measured leakage current based on the current detection results of the monitored circuit and the test current output line, A calculation unit that generates information regarding the detection accuracy of the leakage current detection unit based on a first measured leakage current acquired by the leakage current detection unit when the test current is not being output, and a second measured leakage current acquired by the leakage current detection unit when the test current is being output. A phase difference calculation unit for detecting the phase difference of the measured leakage current with respect to the reference voltage, Equipped with, The leakage current detection unit calculates the effective value of the first measured leakage current and the effective value of the second measured leakage current. The calculation unit calculates the change in leakage current by performing a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected by the phase difference calculation unit for the first measured leakage current, the second measured phase difference detected by the phase difference calculation unit for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current. Insulation monitoring device.

2. The aforementioned arithmetic unit, The terminal measurement current, which is the result of detecting the test current by the measurement terminal, is obtained from the measurement terminal. Based on the terminal measurement current and the change in leakage current, the detection accuracy of the leakage current detection unit is diagnosed. The insulation monitoring device according to claim 1.

3. The calculation unit diagnoses the detection accuracy of the leakage current detection unit based on the output value of the test current and the change in the leakage current. The insulation monitoring device according to claim 1 or 2.

4. The calculation unit calculates the phase difference of the leakage current change with respect to the reference voltage. An insulation monitoring device according to any one of claims 1 to 3.

5. The calculation unit calculates a vector component of the leakage current change that is parallel to the test current. An insulation monitoring device according to any one of claims 1 to 4.

6. The system further includes a display unit that displays the change in leakage current. An insulation monitoring device according to any one of claims 1 to 5.

7. The display unit displays the phase difference of the leakage current change with respect to the reference voltage. The insulation monitoring device according to claim 6.

8. A reference voltage detection unit that detects the voltage applied between any two phases of the monitored AC circuit and acquires it as a reference voltage, A test current output unit capable of outputting a test current synchronized with the aforementioned reference voltage to a test current output line, A leakage current detection unit detects the leakage current, including the test current, flowing through the monitored circuit and the test current output line, and acquires it as a measured leakage current. A calculation unit that generates information regarding the detection accuracy of the leakage current detection unit based on a first measured leakage current detected by the leakage current detection unit when the test current is not being output, and a second measured leakage current detected by the leakage current detection unit when the test current is being output. A phase difference calculation unit for detecting the phase difference of the measured leakage current with respect to the reference voltage, Equipped with, The leakage current detection unit calculates the effective value of the first measured leakage current and the effective value of the second measured leakage current. The calculation unit calculates the change in leakage current by performing a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected by the phase difference calculation unit for the first measured leakage current, the second measured phase difference detected by the phase difference calculation unit for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current. An operational test system for insulation monitoring devices.

9. An operational test method in which a computer generates information regarding the detection accuracy of leakage current in an insulation monitoring device that detects leakage current in an AC circuit under monitoring, A reference voltage detection step, which detects the voltage applied between any two phases of the monitored circuit and acquires it as a reference voltage, A first measured leakage current acquisition step, which involves detecting the leakage current flowing through the monitored electrical circuit and acquiring it as a first measured leakage current, A test current output step that outputs a test current synchronized with the aforementioned reference voltage to a test current output line, A second measured leakage current acquisition step, which detects the leakage current including the test current flowing through the monitored circuit and the test current output line when the test current is being output and acquires it as a second measured leakage current, A calculation step that generates information regarding the detection accuracy based on the first measured leakage current and the second measured leakage current, A phase difference calculation step for detecting the phase difference of the first measured leakage current with respect to the reference voltage and the phase difference of the second measured leakage current with respect to the reference voltage, Equipped with, The first measurement leakage current acquisition step calculates the effective value of the first measurement leakage current, The second measurement leakage current acquisition step calculates the effective value of the second measurement leakage current, The calculation step calculates the change in leakage current by performing a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected in the phase difference calculation step for the first measured leakage current, the second measured phase difference detected in the phase difference calculation step for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current. Method for testing the operation of an insulation monitoring device.

10. An operational test program that generates information regarding the detection accuracy of leakage current for an insulation monitoring device that detects leakage current in an AC circuit under monitoring, A reference voltage detection step, which detects the voltage applied between any two phases of the monitored circuit and acquires it as a reference voltage, A first measured leakage current acquisition step, which involves detecting the leakage current flowing through the monitored electrical circuit and acquiring it as a first measured leakage current, A test current output step that outputs a test current synchronized with the aforementioned reference voltage to a test current output line, A second measured leakage current acquisition step, which detects the leakage current including the test current flowing through the monitored circuit and the test current output line when the test current is being output and acquires it as a second measured leakage current, A calculation step that generates information regarding the detection accuracy based on the first measured leakage current and the second measured leakage current, A phase difference calculation step for detecting the phase difference of the first measured leakage current with respect to the reference voltage and the phase difference of the second measured leakage current with respect to the reference voltage, This is achieved by computer, The first measurement leakage current acquisition step includes calculating the effective value of the first measurement leakage current. The second measurement leakage current acquisition step includes calculating the effective value of the second measurement leakage current. The calculation step includes calculating the change in leakage current by performing a vector operation on the first measured leakage current and the second measured leakage current based on the first measured phase difference detected in the phase difference calculation step for the first measured leakage current, the second measured phase difference detected in the phase difference calculation step for the second measured leakage current, the effective value of the first measured leakage current, and the effective value of the second measured leakage current. Operation test program for insulation monitoring device.

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