Insulation resistance testing device and control method thereof

Abstract

The invention discloses an insulation resistance testing device and a control method thereof. The testing device comprises a voltage measurement module, a switching module, a control module, a grounding terminal, a shielding terminal, two first current detection modules and two first measurement terminals. The switching module is used for changing a switching mode according to the control signal so as to connect the voltage-dividing capacitor or the ground capacitor to the test device for insulation resistance measurement; the first current detection module is used for detecting the current value of the branch; the voltage measurement module is used for measuring a voltage value between the first end of the switching module and the first end of the current detection module; the control module is used for calculating the insulation resistance of the ground capacitor and the insulation resistance between the voltage dividing capacitors according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module. All insulation resistance values of the CVT can be tested only through one-time test wiring, the operation is simple, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of testing technology, and in particular to an insulation resistance testing device and a control method thereof. Background Art

[0002] In order to ensure the safe and stable operation of the power system, it is usually necessary to conduct power outage preventive tests on power equipment regularly. Since insulation resistance is an important parameter for judging the insulation condition of equipment, many power equipment require insulation resistance tests when conducting power outage preventive tests. During the insulation resistance test of the capacitor voltage transformer (CVT), it is necessary to measure the inter-electrode insulation resistance of each voltage-dividing capacitor and the insulation resistance of the capacitor to ground at the low-voltage end of the CVT. Depending on the voltage level, the number of voltage-dividing capacitors of the CVT is also different. The CVT with a voltage level of 110kV has 2 voltage-dividing capacitors, and the CVT with a voltage level of 220kV has 3 voltage-dividing capacitors. Therefore, 3 and 4 insulation resistance values ​​need to be measured for the CVT with a voltage level of 110kV and 220kV, respectively.

[0003] At present, conventional insulation resistance test devices are used for measurement, which can only measure one insulation resistance value each time. After the measurement is completed, the test wiring is replaced to measure the next insulation resistance value. The wiring needs to be changed frequently, which greatly affects the test efficiency. Summary of the invention

[0004] The invention provides an insulation resistance testing device and a control method thereof, which can test all insulation resistance values ​​of a CVT by only performing a test wiring once, is simple to operate, and improves the test efficiency.

[0005] In a first aspect, an embodiment of the present invention provides an insulation resistance testing device for measuring the insulation resistance of the capacitor to ground at the low-voltage end of a capacitive voltage transformer and the insulation resistance between the electrodes of each voltage-dividing capacitor. The insulation resistance testing device includes: a voltage measuring module, a switching module, a control module, a grounding terminal, a shielding terminal, two first current detection modules and two first measuring terminals; the first measuring terminal is used to be electrically connected to the voltage-dividing capacitor and the capacitor to ground; the control module is connected to the switching module and is used to send a control signal to the switching module; the first end of the switching module is connected to the first end of the voltage measuring module, the second end of the switching module is connected to the second end of the voltage detection module, the third end of the switching module is electrically connected to the grounding terminal, and the fourth end of the switching module is electrically connected to the shielding terminal. The switching module is used to change the switching mode according to the control signal to connect at least one of the voltage-dividing capacitor and the ground capacitor to the test device for insulation resistance measurement; the first end of the first current detection module is connected to the second end of the switching module, and the second end of the first current detection module is connected to the first measuring terminal in a one-to-one correspondence, and the first current detection module is used to detect the current value of the branch; the voltage measurement module is used to measure the voltage value between the first end of the switching module and the first end of the first current detection module; the control module is also communicated with the voltage measurement module and the first current detection module, and the control module is also used to calculate the insulation resistance of the ground capacitor and the insulation resistance between each voltage-dividing capacitor pole according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module.

[0006] Optionally, the switching module includes a first switch and a second switch; the control end of the first switch is connected to the first output end of the control module, the first end of the first switch serves as the first end of the switching module, and the second end of the first switch serves as the third end of the switching module; the control end of the second switch is connected to the second output end of the control module, the first end of the second switch serves as the second end of the switching module, the second end of the second switch serves as the fourth end of the switching module, and the third end of the second switch is connected to the first end of the first switch.

[0007] Optionally, the insulation resistance testing device also includes N second current detection modules, N third switches and N second measurement terminals; N is an integer greater than or equal to 1; the first end of the i-th second current detection module is connected to the second end of the switching module, the second end of the i-th second current detection module is connected to the first end of the i-th third switch, the second end of the i-th third switch is connected to the i-th second measurement terminal, and the second current detection module is used to detect the current value of the branch; i is an integer greater than or equal to 1 and less than or equal to N; the third end of the first third switch is electrically connected to the shielding terminal, and the third end of the j-th third switch is connected to the j-1-th second measurement terminal; j is an integer greater than or equal to 2 and less than or equal to N.

[0008] Optionally, the insulation resistance testing device also includes a DC voltage generating module; the control end of the DC voltage generating module is connected to the control module, the first end of the DC voltage generating module is connected to the first end of the switching module, and the second end of the DC voltage generating module is connected to the second end of the voltage detection module, for determining whether to output a DC voltage according to a control signal.

[0009] Optionally, the DC voltage generating module includes a DC power supply and a fourth switch; the control end of the fourth switch serves as the control end of the DC voltage generating module, the first end of the fourth switch serves as the first end of the DC voltage generating module, the second end of the fourth switch is connected to the positive end of the DC power supply, and the negative end of the DC power supply serves as the second end of the DC voltage generating module.

[0010] Optionally, the control signal includes a third control signal, and the insulation resistance testing device also includes a self-discharge module, the first end of the self-discharge module is connected to the first end of the switching module, and the second end of the self-discharge module is connected to the second end of the switching module, and is used to discharge the two ends of at least one of the capacitors to less than or equal to a preset voltage according to the received third control signal after at least one of the voltage-dividing capacitor and the ground capacitor is connected to the testing device for a preset time.

[0011] Optionally, the self-discharge module includes a first resistor and a fifth switch; the first end of the fifth switch serves as the first end of the self-discharge module, the second end of the fifth switch is connected to the first end of the first resistor, and the second end of the first resistor serves as the second end of the self-discharge module.

[0012] In a second aspect, the present invention provides a control method for an insulation resistance testing device, which is used for the insulation resistance testing device provided by any embodiment of the present invention, and the control method includes: a control module sends a control signal to a switching module; the switching module changes a switching mode according to the control signal to connect at least one of a voltage-dividing capacitor and a ground capacitor to the testing device for insulation resistance measurement; a first current detection module detects the current value of the branch; a voltage measurement module measures the voltage value between a first end of the switching module and a first end of the current detection module; and the control module calculates the insulation resistance of the ground capacitor and the insulation resistance between the electrodes of each voltage-dividing capacitor according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module.

[0013] Optionally, the control signal also includes a first control signal and a second control signal; the step of the control module sending the control signal to the switching module includes: the control module sends the first control signal to the switching module according to the received test mode instruction; when the voltage across the measured capacitor is discharged to less than or equal to a preset voltage, the control module sends a second control signal to the switching module; wherein the measured capacitor includes a ground capacitor and / or at least one voltage-dividing capacitor; the step of the switching module changing the switching mode according to the control signal to connect the voltage-dividing capacitor or the ground capacitor to the test device for insulation resistance measurement includes: the switching module connects at least the ground capacitor to the test device for insulation resistance measurement according to the first control signal; the switching module connects the voltage-dividing capacitor to the test device for insulation resistance measurement according to the second control signal.

[0014] Optionally, the insulation resistance testing device also includes a self-discharge module, and the control signal includes a third control signal; the step of the control module sending a control signal to the switching module also includes: after at least one of the voltage-dividing capacitor and the ground capacitor is connected to the testing device for a preset time, the control module sends the third control signal to the self-discharge module; the control method also includes: the self-discharge module discharges the voltage across at least one of the ground capacitor and the voltage-dividing capacitor to less than or equal to a preset voltage according to the third control signal.

[0015] The insulation resistance test device provided by the embodiment of the present invention includes a voltage measurement module, a switching module, a control module, a ground terminal, a shielding terminal, two first current detection modules and two first measurement terminals. The switching module can change the switch mode under the control of the control module, and can connect at least one of the voltage-dividing capacitor and the ground capacitor to the test device. In this way, after one wiring is completed, the connection of different capacitors can be achieved by changing the internal switch state of the switching module without re-wiring the external wiring. At the same time, in the case of one test wiring, the control module controls the switching module to change the switch mode according to the preset program and algorithm, so that the test device can measure each voltage-dividing capacitor and the ground capacitor in turn. When measuring each capacitor, the control module uses the voltage value measured by the voltage measurement module and the current value measured by the first current detection module to calculate the insulation resistance according to Ohm's law. This integrated design avoids the errors and complexity caused by multiple wirings, and improves the test efficiency and accuracy.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a structural schematic diagram of an insulation resistance testing device provided by an embodiment of the present invention;

[0019] Figure 2 This is a wiring diagram of an insulation resistance test device provided by an embodiment of the present invention for measuring a 110kV capacitive voltage transformer;

[0020] Figure 3 This is a wiring diagram of an insulation resistance test device provided by an embodiment of the present invention for measuring a 220kV capacitive voltage transformer;

[0021] Figure 4 is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention;

[0022] Figure 5 is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention;

[0023] Figure 6 is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention;

[0024] Figure 7 This is a wiring diagram of an insulation resistance test device provided by an embodiment of the present invention for measuring a 500kV capacitive voltage transformer;

[0025] Figure 8 is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention;

[0026] Fig. 9 is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention;

[0027] Fig.10 This is a wiring diagram of another insulation resistance test device provided by an embodiment of the present invention for measuring a 110kV capacitive voltage transformer;

[0028] Fig.11 is a flow chart of a control method of an insulation resistance testing device provided by an embodiment of the present invention;

[0029] Fig.12 This is a flow chart of a control method for another insulation resistance testing device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] Figure 1 It is a structural schematic diagram of an insulation resistance testing device provided by an embodiment of the present invention. Figure 2 The present invention provides an insulation resistance test device for measuring a wiring diagram of a 110kV capacitive voltage transformer. Figure 3 The present invention provides an insulation resistance test device for measuring the wiring diagram of a 220kV capacitor voltage transformer. The insulation resistance test device is used to measure the insulation resistance of the capacitor to ground at the low voltage end of the capacitor voltage transformer and the insulation resistance between the poles of each voltage dividing capacitor.

[0033] refer to Figures 1 to 3 The insulation resistance testing device includes: a voltage measuring module 11, a switching module 12, a control module 13, a grounding terminal E, a shielding terminal G, two first current detection modules 14 and two first measuring terminals L1; the first measuring terminal L1 is used to be electrically connected to the voltage dividing capacitor C1 and the ground capacitor CN1.

[0034] The control module 13 is connected to the switching module 12 and is used to send a control signal to the switching module 12 .

[0035] A first end of the switching module 12 is connected to a first end of the voltage measuring module 11, a second end of the switching module 12 is connected to a second end of the voltage detecting module 11, a third end of the switching module 12 is electrically connected to a ground terminal E, and a fourth end of the switching module 12 is electrically connected to a shielding terminal G. The switching module 12 is used to change a switching mode according to a control signal to connect at least one of the voltage-dividing capacitor C1 and the ground capacitor CN1 to a test device for insulation resistance measurement.

[0036] The first end of the first current detection module 14 is connected to the second end of the switching module 12 , and the second end of the first current detection module 14 is connected to the first measurement terminal L1 in a one-to-one correspondence. The first current detection module 14 is used to detect the current value of the branch.

[0037] The voltage measuring module 11 is used to measure a voltage value between a first end of the switching module 12 and a first end of the first current detecting module 14 .

[0038] The control module 13 is also connected to the voltage measurement module 11 and the first current detection module 14 for communication. The control module 13 is also used to calculate the insulation resistance of the ground capacitor CN1 and the insulation resistance between the electrodes of each voltage-dividing capacitor C1 according to the voltage value measured by the voltage measurement module 11 and the current value measured by the first current detection module 14.

[0039] Specifically, the voltage measurement module 11 is a module for measuring the voltage value between two points in a circuit. It can convert a voltage signal into an electrical signal (such as an analog signal or a digital signal) that can be processed by the control module. Exemplarily, the voltage measurement module 11 can be a DC voltmeter.

[0040] The switching module 12 may be a module including at least two switches, where the switch includes a mechanical switch, or a switch that implements on-off control through an electrical signal, or a switch that implements on-off control according to the characteristics of the component itself.

[0041] The control module 13 may include a microcontroller. Optionally, the control module 13 may include a single chip microcomputer, a digital signal processor (DSP) or a field programmable gate array (FPGA).

[0042] The first current detection module 14 is a module for detecting the current value of the branch. It can convert the current signal into an electrical signal (such as an analog signal or a digital signal) that can be processed by the control module, so that the control module 13 calculates the insulation resistance value according to the current value and the voltage value. Exemplarily, the first current detection module 14 can be a DC ammeter.

[0043] refer to Figure 1 and Figure 2 The working process of the insulation resistance test device to measure 110kV capacitive voltage transformer is as follows:

[0044] The control signal includes a first control signal and a second control signal. After the insulation resistance test device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction. The switching module 12 connects the ground capacitor CN1 to the test device to measure the insulation resistance according to the first control signal. After the ground capacitor CN1 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11 and the current value I1 measured by the first current detection module 141. CN1 =U / I1. The embodiment of the present invention does not specifically limit the value of the preset time, and can be set according to actual conditions. For example, the preset time can be 60 seconds.

[0045] Then, the power supply is cut off, the ground capacitor CN1 starts to discharge, the voltage measurement module 11 measures the voltage across the ground capacitor CN1 in real time, and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 is discharged to less than or equal to the preset voltage based on the data uploaded by the voltage measurement module 11, the control module 13 sends a second control signal to the switching module 12. The embodiment of the present invention does not specifically limit the value of the preset voltage, and it can be set according to actual conditions. For example, the preset voltage can be 1V.

[0046] The switching module 12 connects the voltage-dividing capacitor C1 to the test device for insulation resistance measurement according to the second control signal. After the voltage-dividing capacitor C1 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the first voltage-dividing capacitor C11 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. C11 =U / I1, calculate the insulation resistance R of the second voltage divider capacitor C12 C12 =U / I2. Then, the power supply is cut off, and the voltage-dividing capacitor C1 starts to discharge. When the voltage across the voltage-dividing capacitor C1 is discharged to be less than or equal to the preset voltage, it indicates that the discharge is complete and the measurement is finished.

[0047] refer to Figure 1 and Figure 3 The working process of the insulation resistance test device to measure the 220kV capacitive voltage transformer is as follows:

[0048] After the insulation resistance test device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction. The switching module 12 connects the ground capacitor CN1 and the third voltage-dividing capacitor C13 to the test device for insulation resistance measurement according to the first control signal. After the ground capacitor CN1 and the third voltage-dividing capacitor C13 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. CN1 =U / I1, calculate the insulation resistance R of the third voltage divider capacitor C13 C13 =U / I2.

[0049] Then, the power supply is cut off, and the ground capacitor CN1 and the third voltage-dividing capacitor C13 begin to discharge. The voltage measuring module 11 measures the voltage across the ground capacitor CN1 and the third voltage-dividing capacitor C13 in real time, and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 and the third voltage-dividing capacitor C13 is discharged to be less than or equal to the preset voltage based on the data uploaded by the voltage measuring module 11, the control module 13 sends a second control signal to the switching module 12.

[0050] The switching module 12 connects the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 to the test device for insulation resistance measurement according to the second control signal. After the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the first voltage-dividing capacitor C11 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. C11 =U / I1, calculate the insulation resistance R of the second voltage divider capacitor C12 C12 =U / I2. Then, the power supply is cut off, and the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 begin to discharge. When the voltage across the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 is discharged to be less than or equal to the preset voltage, it indicates that the discharge is complete and the measurement is finished.

[0051] It should be noted that the voltage value U measured by the voltage measurement module 11 each time is only represented by the same symbol, which does not mean that the voltage value U measured by the voltage measurement module 11 each time is the same. Similarly, the current value I1 measured by the first first current detection module 141 each time can be the same or different. The current value I2 measured by the second first current detection module 142 each time can be the same or different.

[0052] The insulation resistance test device provided by the embodiment of the present invention includes a voltage measurement module, a switching module, a control module, a ground terminal, a shielding terminal, two first current detection modules and two first measurement terminals. The switching module can change the switch mode under the control of the control module, and can connect at least one of the voltage-dividing capacitor and the ground capacitor to the test device. In this way, after one wiring is completed, the connection of different capacitors can be achieved by changing the internal switch state of the switching module without re-wiring the external wiring. At the same time, in the case of one test wiring, the control module controls the switching module to change the switch mode according to the preset program and algorithm, so that the test device can measure each voltage-dividing capacitor and the ground capacitor in turn. When measuring each capacitor, the control module uses the voltage value measured by the voltage measurement module and the current value measured by the first current detection module to calculate the insulation resistance according to Ohm's law. This integrated design avoids the errors and complexity caused by multiple wirings, and improves the test efficiency and accuracy.

[0053] Figure 4 Schematic diagram of another insulation resistance test device provided by an embodiment of the present invention. Figure 4 As shown, optionally, the switching module 12 includes a first switch S1 and a second switch S2;

[0054] The control end of the first switch S1 is connected to the first output end of the control module 13, the first end a1 of the first switch S1 serves as the first end of the switching module 12, and the second end a2 of the first switch S1 serves as the third end of the switching module 12.

[0055] The control end of the second switch S2 is connected to the second output end of the control module 13, the first end b1 of the second switch S2 serves as the second end of the switching module 12, the second end b2 of the second switch S2 serves as the fourth end of the switching module 12, and the third end b3 of the second switch S2 is connected to the first end a1 of the first switch S1.

[0056] Specifically, the first switch S1 may be a single-pole single-throw switch, and the second switch S2 may be a single-pole double-throw switch. The first switch S1 has two switching modes, the switching mode 1 of the first switch S1 is that the first end a1 and the second end a2 are connected, and the switching mode 2 of the first switch S1 is that the first end a1 and the second end a2 are not connected. The second switch S2 has two switching modes, the switching mode 1 of the second switch S2 is that the first end b1 and the second end b2 are connected, and the second end b2 and the third end b3 are not connected; the switching mode 2 of the second switch S2 is that the first end b1 and the second end b2 are not connected, and the second end b2 and the third end b3 are connected.

[0057] refer to Figure 2 and Figure 4 The working process of the insulation resistance test device to measure 110kV capacitive voltage transformer is as follows:

[0058] After the insulation resistance test device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction, controls the first switch S1 to switch mode 1 and the second switch S2 to switch mode 1, connects the ground capacitor CN1 to the test device for insulation resistance measurement, and after the ground capacitor CN1 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11 and the current value I1 measured by the first current detection module 141. CN1 =U / I1.

[0059] Then, the power supply is cut off, and the ground capacitor CN1 starts to discharge. The voltage measuring module 11 measures the voltage across the ground capacitor CN1 in real time and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 is discharged to be less than or equal to the preset voltage based on the data uploaded by the voltage measuring module 11, the control module 13 sends a second control signal to the switching module 12.

[0060] The second control signal controls the first switch S1 to work in switch mode 2 and controls the second switch S2 to work in switch mode 2. At this time, the switching module 12 connects the voltage-dividing capacitor C1 to the test device to measure the insulation resistance. After the voltage-dividing capacitor C1 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the first voltage-dividing capacitor C11 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. C11 =U / I1, calculate the insulation resistance R of the second voltage divider capacitor C12 C12 =U / I2. Then, the power supply is cut off, and the voltage-dividing capacitor C1 starts to discharge. When the voltage across the voltage-dividing capacitor C1 is discharged to be less than or equal to the preset voltage, it indicates that the discharge is complete and the measurement is finished.

[0061] refer to Figure 3 and Figure 4 The working process of the insulation resistance test device to measure the 220kV capacitive voltage transformer is as follows:

[0062] After the insulation resistance test device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction. The first control signal controls the first switch S1 to switch mode 1 and controls the second switch S2 to switch mode 1. At this time, the switching module 12 connects the ground capacitor CN1 and the third voltage-dividing capacitor C13 to the test device for insulation resistance measurement. After the ground capacitor CN1 and the third voltage-dividing capacitor C13 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. CN1 =U / I1, calculate the insulation resistance R of the third voltage divider capacitor C13 C13 =U / I2.

[0063] Then, the power supply is cut off, and the ground capacitor CN1 and the third voltage-dividing capacitor C13 begin to discharge. The voltage measuring module 11 measures the voltage across the ground capacitor CN1 and the third voltage-dividing capacitor C13 in real time, and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 and the third voltage-dividing capacitor C13 is discharged to be less than or equal to the preset voltage based on the data uploaded by the voltage measuring module 11, the control module 13 sends a second control signal to the switching module 12.

[0064] The second control signal controls the first switch S1 to work in switch mode 2, and controls the second switch S2 to work in switch mode 2. At this time, the switching module 12 connects the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 to the test device for insulation resistance measurement. After the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the first voltage-dividing capacitor C11 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. C11 =U / I1, calculate the insulation resistance R of the second voltage divider capacitor C12 C12 =U / I2. Then, the power supply is cut off, and the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 begin to discharge. When the voltage across the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 is discharged to be less than or equal to the preset voltage, it indicates that the discharge is complete and the measurement is finished.

[0065] Figure 5 It is a structural schematic diagram of another insulation resistance testing device provided by an embodiment of the present invention. Figure 6 Schematic diagram of another insulation resistance test device provided by an embodiment of the present invention. Figure 5 and Figure 6 The insulation resistance testing device further includes N second current detection modules 15, N third switches S3 and N second measurement terminals L2; ​​N is an integer greater than or equal to 1.

[0066] The first end of the i-th second current detection module 15 is connected to the second end of the switching module 12, the second end of the i-th second current detection module 15 is connected to the first end c1 of the i-th third switch S3, the second end c2 of the i-th third switch S3 is connected to the i-th second measurement terminal L2, and the second current detection module 15 is used to detect the current value of the branch where it is located; i is an integer greater than or equal to 1 and less than or equal to N.

[0067] The third end c3 of the first third switch S3 is electrically connected to the shielding terminal G, and the third end c3 of the jth third switch S3 is connected to the j-1th second measuring terminal L2; j is an integer greater than or equal to 2 and less than or equal to N. Figure 5 The case of N=1 is shown schematically. Figure 6 The case where N=2 is schematically shown. The embodiment of the present invention does not specifically limit the value of N, and the value of N can be set according to actual needs.

[0068] Specifically, the second current detection module 15 may be an ammeter, and the third switch S3 may be a single-pole double-throw switch. The third switch S3 has two switching modes. The switching mode 1 of the third switch S3 is that the first end c1 and the second end c2 are connected, and the second end c2 and the third end c3 are not connected; the switching mode 2 of the second switch S2 is that the first end c1 and the second end c2 are not connected, and the second end c2 and the third end c3 are connected.

[0069] Figure 7 This is a wiring diagram of an insulation resistance test device provided by an embodiment of the present invention for measuring a 500kV capacitive voltage transformer. Figure 5 and Figure 7 The working process of the insulation resistance test device to measure 500kV capacitive voltage transformer is as follows:

[0070] After the insulation resistance test device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction. The first control signal controls the first switch S1 to switch mode 1, controls the second switch S2 to switch mode 1, and controls the third switch S3 to switch mode 1. At this time, the switching module 12 connects the ground capacitor CN1 and the fourth voltage-dividing capacitor C14 to the test device for insulation resistance measurement. After the ground capacitor CN1 and the fourth voltage-dividing capacitor C14 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. CN1 =U / I1, calculate the insulation resistance R of the fourth voltage divider capacitor C14 C14 =U / I2.

[0071] Then, the power supply is cut off, and the ground capacitor CN1 and the fourth voltage-dividing capacitor C14 begin to discharge. The voltage measuring module 11 measures the voltage across the ground capacitor CN1 and the third voltage-dividing capacitor C14 in real time, and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 and the fourth voltage-dividing capacitor C14 is discharged to less than or equal to the preset voltage based on the data uploaded by the voltage measuring module 11, the control module 13 sends a second control signal to the switching module 12.

[0072] The second control signal controls the first switch S1 to work in switch mode 2, controls the second switch S2 to work in switch mode 2, and controls the third switch S3 to work in switch mode 2. At this time, the switching module 12 connects the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 to the test device for insulation resistance measurement. After the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 are connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the first voltage-dividing capacitor C11 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142. C11 =U / I1, calculate the insulation resistance R of the second voltage divider capacitor C12 C12 =U / I2. Then, the power supply is cut off, and the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 begin to discharge. When the voltage across the first voltage-dividing capacitor C11 and the second voltage-dividing capacitor C12 is discharged to be less than or equal to the preset voltage, the control module 13 sends a fourth control signal to the switching module 12.

[0073] The fourth control signal controls the first switch S1 to work in switch mode 2, controls the second switch S2 to work in switch mode 2, and controls the third switch S3 to work in switch mode 1. At this time, the switching module 12 connects the third voltage-dividing capacitor C13 to the test device for insulation resistance measurement. After the third voltage-dividing capacitor C13 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance R of the third voltage-dividing capacitor C13 according to the voltage value U measured by the voltage measurement module 11 and the current value I3 measured by the second current detection module 15. C13 =U / I3, then, the power supply is cut off, and the third voltage-dividing capacitor C13 starts to discharge. When the voltage across the third voltage-dividing capacitor C13 is discharged to be less than or equal to the preset voltage, it indicates that the discharge is completed and the measurement is finished.

[0074] Figure 8 Schematic diagram of another insulation resistance test device provided by an embodiment of the present invention. Figure 8 Optionally, the insulation resistance testing device also includes a DC voltage generating module 16.

[0075] The control end of the DC voltage generating module 16 is connected to the control module 13, the first end of the DC voltage generating module is connected to the first end of the switching module 12, and the second end of the DC voltage generating module 16 is connected to the second end of the voltage detection module 11, for determining whether to output a DC voltage according to a control signal.

[0076] Specifically, when the control module 12 outputs the first control signal, the second control signal and the fourth control signal, the DC voltage generating module 16 outputs a DC voltage, and when the control module 12 outputs the third control signal, the DC voltage generating module 16 does not output a DC voltage.

[0077] Continue to refer Figure 8 Optionally, the DC voltage generating module 16 includes a DC power supply DC1 and a fourth switch S4. The control end of the fourth switch S4 serves as the control end of the DC voltage generating module, the first end of the fourth switch serves as the first end of the DC voltage generating module, the second end of the fourth switch is connected to the positive end of the DC power supply, and the negative end of the DC power supply serves as the second end of the DC voltage generating module.

[0078] Specifically, the DC power supply DC1 can generate a DC voltage of 0-2500 V. The fourth switch S4 can be a single-pole single-throw switch. The fourth switch S4 has two switching modes. The first switching mode of the fourth switch S4 is that the first end d1 and the second end d2 are connected, and the second switching mode of the fourth switch S4 is that the first end d1 and the second end d2 are not connected.

[0079] When the control module 12 outputs the first control signal, the second control signal and the fourth control signal, the fourth switch S4 works in switch mode 1, and the DC power supply DC1 can output a DC voltage of 0-2500 V. When the control module 12 outputs the third control signal, the fourth switch S4 works in switch mode 2, and the DC power supply DC1 cannot output a DC voltage.

[0080] Fig. 9 Schematic diagram of another insulation resistance test device provided by an embodiment of the present invention. Fig. 9 , the control signal includes a third control signal, the insulation resistance testing device also includes a self-discharge module 16, a first end of the self-discharge module 16 is connected to the first end of the switching module 12, and a second end of the self-discharge module 16 is connected to the second end of the switching module 12, and is used to discharge the two ends of at least one of the ground capacitor and the voltage-dividing capacitor to a voltage less than or equal to a preset voltage according to the received third control signal after at least one of the voltage-dividing capacitor and the ground capacitor is connected to the testing device for a preset time.

[0081] Continue to refer Fig. 9 Optionally, the self-discharge module 16 includes a first resistor R1 and a fifth switch S5; the first end of the fifth switch S5 serves as the first end of the self-discharge module 16, the second end of the fifth switch S5 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 serves as the second end of the self-discharge module 16.

[0082] Specifically, the fifth switch S5 may be a single-pole single-throw switch. The fifth switch S5 has two switching modes, a switching mode 1 of the fifth switch S5 is that the first end e1 and the second end e2 are connected, and a switching mode 2 of the fifth switch S5 is that the first end e1 and the second end e2 are not connected.

[0083] Fig.10 This is another wiring diagram of an insulation resistance test device provided by an embodiment of the present invention for measuring a 110kV capacitive voltage transformer. Fig. 9 and Fig.10 The working process of the insulation resistance test device to measure 110kV capacitive voltage transformer is as follows:

[0084] After the insulation resistance testing device is powered on and starts working, the control module 13 sends a first control signal to the switching module 12 according to the received test mode instruction, controls the first switch S1 to work in switch mode 1, the second switch S2 to work in switch mode 1, the fourth switch S4 to work in switch mode 1, and the fifth switch S5 to work in switch mode 2, and connects the ground capacitor CN1 to the testing device for insulation resistance measurement. After the ground capacitor CN1 is connected to the testing device for a preset time, the control module 13 can calculate the insulation resistance RCN1=U / I1 of the ground capacitor CN1 according to the voltage value U measured by the voltage measurement module 11 and the current value I1 measured by the first first current detection module 141, and sends a third control signal to the DC voltage generating module 16 and the self-discharge module 17.

[0085] Then, the third control signal controls the fourth switch S4 to work in switch mode two, the fifth switch S5 to work in switch mode one, the ground capacitor CN1 starts to discharge, the voltage measuring module 11 measures the voltage across the ground capacitor CN1 in real time, and uploads it to the control module 13. When the control module 13 determines that the voltage across the ground capacitor CN1 is discharged to be less than or equal to the preset voltage based on the data uploaded by the voltage measuring module 11, the control module 13 sends a second control signal to the switching module 12.

[0086] The second control signal controls the first switch S1 to work in switch mode 2, and controls the second switch S2 to work in switch mode 2. At this time, the switching module 12 connects the voltage-dividing capacitor C1 to the test device to measure the insulation resistance. After the voltage-dividing capacitor C1 is connected to the test device for a preset time, the control module 13 can calculate the insulation resistance RC11=U / I1 of the first voltage-dividing capacitor C11 and the insulation resistance RC12=U / I2 of the second voltage-dividing capacitor C12 according to the voltage value U measured by the voltage measurement module 11, the current value I1 measured by the first first current detection module 141, and the current value I2 measured by the second first current detection module 142.

[0087] Then, the third control signal is sent to the DC voltage generating module 16 and the self-discharging module 17 again. The third control signal controls the fourth switch S4 to work in the switching mode 2 again, and the fifth switch S5 to work in the switching mode 1. The voltage-dividing capacitor C1 starts to discharge. When the voltage across the voltage-dividing capacitor C1 is discharged to less than or equal to the preset voltage, it indicates that the discharge is completed and the measurement is finished. That is to say, after at least one of the voltage-dividing capacitor C1 and the ground capacitor CN1 is connected to the test device for a preset time, the control module 12 sends the third control signal to the DC voltage generating module 16 and the self-discharging module 17. The fourth switch S4 in the DC voltage generating module 16 works in the switching mode 2 in response to the third control signal, that is, the fourth switch S4 is disconnected, the DC power supply DC1 cannot output the DC voltage, and the self-discharging module 17 discharges the voltage across at least one of the ground capacitor CN1 and the voltage-dividing capacitor C1 to less than or equal to the preset voltage according to the third control signal.

[0088] In some embodiments, the insulation resistance test device also includes a control panel, which is connected to the control module 13 in communication, and the tester can send a test mode instruction to the control module 13 through the control panel. The test mode instruction can include three test mode instructions of 110kV, 220kV and 500kV. The control panel can be a physical human-computer interaction interface. For example, it can be a panel with buttons and a display screen, the buttons are used to input operation instructions (such as selecting 110kV, 220kV or 500kV test mode), and the display screen is used to display the current test status information, such as the currently selected test mode, whether the device is ready for testing, etc.

[0089] Based on the same inventive concept, an embodiment of the present invention further provides a control method for an insulation resistance testing device. Fig.11 1 is a flow chart of a control method of an insulation resistance test device provided by an embodiment of the present invention. The technical solution of the embodiment of the present invention can be executed by the insulation resistance test device provided by any embodiment of the present invention. Fig.11 As shown, the control method provided by the embodiment of the present invention specifically includes the following steps:

[0090] S101: The control module sends a control signal to the switching module.

[0091] S102: The switching module changes the switching mode according to the control signal to connect at least one of the voltage-dividing capacitor and the ground capacitor to the test device to measure the insulation resistance.

[0092] S103: The first current detection module detects the current value of the branch where it is located.

[0093] S104: The voltage measuring module measures a voltage value between a first end of the switching module and a first end of the current detecting module.

[0094] S105 , the control module calculates the insulation resistance of the ground capacitor and the insulation resistance between the electrodes of each voltage-dividing capacitor according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module.

[0095] Fig.12 1 is a flow chart of another control method of an insulation resistance test device provided by an embodiment of the present invention. The control signal also includes a first control signal, a second control signal and a third control signal. Fig.12 , the control method comprises:

[0096] S201. The control module sends a first control signal to the switching module according to a received test mode instruction.

[0097] S202: The switching module connects at least the ground capacitance to the test device to measure the insulation resistance according to the first control signal.

[0098] S203: After at least one of the voltage-dividing capacitor and the ground capacitor is connected to the test device for a preset time, the control module sends a third control signal to the self-discharge module.

[0099] S204. The self-discharging module discharges the voltage across at least one of the ground capacitor and the voltage-dividing capacitor to a voltage less than or equal to a preset voltage according to the third control signal.

[0100] S205: When the voltage across the capacitor under test is discharged to a value less than or equal to a preset voltage, the control module sends a second control signal to the switching module.

[0101] The measured capacitance includes a ground capacitance and / or at least one voltage-dividing capacitance.

[0102] S206 . The switching module connects the voltage-dividing capacitor to the testing device to measure the insulation resistance according to the second control signal.

[0103] S207. The first current detection module detects the current value of the branch where it is located.

[0104] S208. The voltage measuring module measures a voltage value between a first end of the switching module and a first end of the current detecting module.

[0105] S209: The control module calculates the insulation resistance of the ground capacitor and the insulation resistance between the electrodes of each voltage-dividing capacitor according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module.

[0106] The similarities between the control method of the insulation resistance test device provided in the embodiment of the present invention and the insulation resistance test device can be referred to the corresponding explanation of the insulation resistance test device, which will not be repeated here.

[0107] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An insulation resistance testing device, characterized in that: Used to measure the insulation resistance of the capacitor to ground at the low-voltage end of the capacitive voltage transformer and the insulation resistance between the voltage-dividing capacitors, the insulation resistance testing device comprises: a voltage measuring module, a switching module, a control module, a grounding terminal, a shielding terminal, two first current detection modules and two first measuring terminals; the first measuring terminals are used to be electrically connected to the voltage-dividing capacitor and the capacitor to ground; The control module is connected to the switching module and is used to send a control signal to the switching module; The first end of the switching module is connected to the first end of the voltage measuring module, the second end of the switching module is connected to the second end of the voltage detecting module, the third end of the switching module is electrically connected to the ground terminal, and the fourth end of the switching module is electrically connected to the shielding terminal. The switching module is used to change the switch mode according to the control signal to connect at least one of the voltage dividing capacitor and the ground capacitor to the test device for insulation resistance measurement; The first end of the first current detection module is connected to the second end of the switching module, the second end of the first current detection module is connected to the first measurement terminal in a one-to-one correspondence, and the first current detection module is used to detect the current value of the branch where it is located; The voltage measuring module is used to measure the voltage value between the first end of the switching module and the first end of the first current detection module; The control module is also communicatively connected with the voltage measurement module and the first current detection module, and is also used to calculate the insulation resistance of the ground capacitor and the insulation resistance between the electrodes of each voltage-dividing capacitor according to the voltage value measured by the voltage measurement module and the current value measured by the first current detection module.

2. The insulation resistance testing device according to claim 1, characterized in that: The switching module includes a first switch and a second switch; The control end of the first switch is connected to the first output end of the control module, the first end of the first switch serves as the first end of the switching module, and the second end of the first switch serves as the third end of the switching module; The control end of the second switch is connected to the second output end of the control module, the first end of the second switch serves as the second end of the switching module, the second end of the second switch serves as the fourth end of the switching module, and the third end of the second switch is connected to the first end of the first switch.

3. The insulation resistance testing device according to claim 1, characterized in that: It also includes N second current detection modules, N third switches and N second measurement terminals; N is an integer greater than or equal to 1; The first end of the i-th second current detection module is connected to the second end of the switching module, the second end of the i-th second current detection module is connected to the first end of the i-th third switch, the second end of the i-th third switch is connected to the i-th second measurement terminal, and the second current detection module is used to detect the current value of the branch where it is located; i is an integer greater than or equal to 1 and less than or equal to N; The third end of the first third switch is electrically connected to the shielding terminal, and the third end of the jth third switch is connected to the j-1th second measuring terminal; j is an integer greater than or equal to 2 and less than or equal to N.

4. The insulation resistance testing device according to claim 1, characterized in that: Also includes a DC voltage generating module; The control end of the DC voltage generating module is connected to the control module, the first end of the DC voltage generating module is connected to the first end of the switching module, and the second end of the DC voltage generating module is connected to the second end of the voltage detection module, and is used to determine whether to output a DC voltage according to the control signal.

5. The insulation resistance testing device according to claim 4, characterized in that: The DC voltage generating module includes a DC power supply and a fourth switch; The control end of the fourth switch serves as the control end of the DC voltage generating module, the first end of the fourth switch serves as the first end of the DC voltage generating module, the second end of the fourth switch is connected to the positive end of the DC power supply, and the negative end of the DC power supply serves as the second end of the DC voltage generating module.

6. The insulation resistance testing device according to claim 1, characterized in that: The control signal includes a third control signal, and the insulation resistance testing device also includes a self-discharge module, a first end of the self-discharge module is connected to the first end of the switching module, and a second end of the self-discharge module is connected to the second end of the switching module, and is used to discharge the two ends of at least one of the capacitors of the capacitor to ground and the voltage-dividing capacitor to a voltage less than or equal to a preset voltage according to the received third control signal after at least one of the voltage-dividing capacitor and the capacitor to ground is connected to the testing device for a preset time.

7. The insulation resistance testing device according to claim 6, characterized in that: The self-discharge module includes a first resistor and a fifth switch; The first end of the fifth switch serves as the first end of the self-discharge module, the second end of the fifth switch is connected to the first end of the first resistor, and the second end of the first resistor serves as the second end of the self-discharge module.

8. A control method for an insulation resistance testing device, characterized in that: For the insulation resistance testing device according to any one of claims 1 to 7, the control method comprises: The control module sends a control signal to the switching module; The switching module changes the switch mode according to the control signal to connect at least one of the voltage-dividing capacitor and the ground capacitor to a test device for insulation resistance measurement; The first current detection module detects the current value of the branch where it is located; The voltage measuring module measures the voltage value between the first end of the switching module and the first end of the current detecting module; The control module calculates the insulation resistance of the ground capacitor and the insulation resistance between the electrodes of each of the voltage-dividing capacitors according to the voltage value measured by the voltage measuring module and the current value measured by the first current detection module.

9. The control method of the insulation resistance testing device according to claim 8, characterized in that: The control signal also includes a first control signal and a second control signal; The step of the control module sending a control signal to the switching module comprises: The control module sends the first control signal to the switching module according to the received test mode instruction; When the voltage across the measured capacitor is discharged to be less than or equal to a preset voltage, the control module sends the second control signal to the switching module; wherein the measured capacitor includes the ground capacitor and / or at least one voltage-dividing capacitor; The step of the switching module changing the switch mode according to the control signal to connect the voltage-dividing capacitor or the ground capacitor to the test device to measure the insulation resistance includes: The switching module at least connects the ground capacitance to a test device to measure insulation resistance according to the first control signal; The switching module connects the voltage-dividing capacitor to a testing device to measure insulation resistance according to the second control signal.

10. The control method of the insulation resistance testing device according to claim 8, characterized in that: The insulation resistance testing device further includes a self-discharge module, and the control signal includes a third control signal; The step of the control module sending a control signal to the switching module further includes: After at least one of the voltage-dividing capacitor and the ground capacitor is connected to the test device for a preset time, the control module sends the third control signal to the self-discharge module; The control method further comprises: The self-discharge module discharges the voltage across at least one of the ground capacitor and the voltage-dividing capacitor to a voltage less than or equal to a preset voltage according to the third control signal.

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