Device and method for testing grounding fault suppression performance of arc extinguishing device

Abstract

The invention relates to a device and method for testing the ground fault suppression performance of an arc extinguishing device, and the device comprises a transformer which comprises a low-voltage side, a high-voltage side and a neutral point, and the high-voltage side is used for outputting a high-voltage three-phase power supply; the first end of the first switch is electrically connected with the low-voltage side, and the second end is connected with a low-voltage input power supply; the device access unit is electrically connected with the neutral point; the harmonic elimination unit is electrically connected with the high-voltage side and used for eliminating output harmonic waves of the high-voltage side; the working condition simulation unit is electrically connected with the high-voltage side; the fault simulation unit is electrically connected with one phase of the high-voltage side; and the data acquisition unit is electrically connected with the transformer. According to the invention, the grounding fault suppression performance of different arc extinguishing devices under different working currents and different types of grounding faults can be tested.

Description

Technical Field

[0001] The invention relates to the technical field of arc extinguishing, and in particular to a device and method for testing the performance of an arc extinguishing device in suppressing ground faults. Background Art

[0002] In nuclear power plants, there are many types of arc extinguishing devices in the power system, including turn-controlled arc extinguishing coils, phase-controlled arc extinguishing coils, and controllable voltage source arc extinguishing devices. Due to the specificity of each power system, the effects of different arc extinguishing devices in different power systems are different, so it is difficult to guarantee the actual effect of the arc extinguishing device in the power system. It is often only detected when a real fault occurs, and it is obviously too late to make adjustments afterwards. Therefore, there is an urgent need for a solution that can test the performance of arc extinguishing devices in suppressing ground faults in different power systems. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a device and method for testing the performance of arc extinguishing device in suppressing ground fault.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing a test device for the performance of arc extinguishing device in suppressing ground fault, comprising: A transformer, comprising a low voltage side, a high voltage side and a neutral point, wherein the high voltage side is used to output a high voltage three-phase power supply; A first switch, a first end of which is electrically connected to the low-voltage side, and a second end of which is used to access a low-voltage input power supply; A device access unit, electrically connected to the neutral point, and used for accessing at least one arc extinguishing device to be tested; A harmonic elimination unit, electrically connected to the high voltage side, for eliminating output harmonics of the high voltage side; A working condition simulation unit, electrically connected to the high voltage side, and used to simulate the high voltage side to output a variety of output currents when the transformer is working; A fault simulation unit, electrically connected to one of the phases on the high voltage side, for simulating a ground fault, wherein the types of the ground fault include a metal ground fault, a resistor ground fault and an arc ground fault; A data acquisition unit is electrically connected to the transformer and is used to collect test data when simulating a ground fault, wherein the test data includes at least one of the arc extinguishing device compensation current, the operating current of the operating condition simulation unit, the fault point current of the fault simulation unit and the fault point voltage of the fault simulation unit.

[0005] Preferably, the operating condition simulation unit comprises: a plurality of third switches, a first end of which is electrically connected to the high voltage side; and A plurality of three-phase capacitors, wherein the first ends of the three-phase capacitors are electrically connected to the high voltage side one by one via the third switch, and the second ends of the three-phase capacitors are electrically connected and grounded at the same time.

[0006] Preferably, the operating condition simulation unit further includes: A plurality of sampling working condition simulation transformers are used to be installed on the high voltage side.

[0007] Preferably, the fault simulation unit comprises: a fourth switch, a first end of which is electrically connected to one phase of the high voltage side; and The fault model is electrically connected between the second end of the fourth switch and the ground, and is used to simulate the occurrence of the metal grounding fault, the resistor grounding fault or the arc grounding fault.

[0008] Preferably, the device access unit comprises: A plurality of second switches, wherein the first ends of the second switches are electrically connected to the neutral point, and the second ends of the second switches are used to be connected to the arc extinguishing device to be tested.

[0009] Preferably, the detuning unit comprises: Fifth switch; A first voltage transformer, a primary side of which is electrically connected to the high voltage side via the fifth switch; and A detuning module is electrically connected to the secondary side of the first voltage transformer.

[0010] Preferably, the data acquisition unit comprises: A first current transformer is coupled to the arc extinguishing device to be tested to measure a compensation current of the arc extinguishing device; A second current transformer, coupled to the primary side of the first voltage transformer, to measure the three-phase to ground current of the detuning unit; a third current transformer, coupled to the three-phase capacitor, to measure the operating current; a fourth current transformer, coupled to the fault model to measure the fault point current; and A second voltage transformer is coupled to the fault model to measure the voltage at the fault point.

[0011] The present invention also constructs a method for testing the performance of arc extinguishing device in suppressing ground fault, which is used for the above-mentioned arc extinguishing device in suppressing ground fault performance testing device, and the testing method comprises: S1. Setting a device under test setting instruction and a working current setting instruction according to a preset test list, wherein the test list includes a plurality of test combinations, and each of the test combinations includes a corresponding device under test setting instruction and a working current setting instruction; S2, outputting the setting instruction of the device to be tested to the device access unit, so that the corresponding arc extinguishing device to be tested is connected to the neutral point of the transformer; S3, outputting the working current setting instruction to the working condition simulation unit, so that the high-voltage side of the transformer simulates the output of the set working current when the transformer is working; S4, controlling the first switch to close; S5. After the first switch is closed, collecting test data through the data collection unit; S6, controlling the fault simulation unit to operate so that the fault simulation unit simulates a ground fault; S7, after collecting the test data, controlling the first switch to be turned off, and determining whether there is a test combination that has not been tested in the test list, if so, setting the device under test setting instruction and the working current setting instruction according to the test combination that has not been tested, and returning to S2, otherwise executing S8; S8. Generate test results based on all collected test data.

[0012] Preferably, the S8 includes: The performance parameters corresponding to each test combination are calculated based on all the test data; wherein the performance parameters include arc detection sensitivity, compensation response time, residual current stabilization time and residual current at the fault point.

[0013] Preferably, in S7, setting the device under test setting instruction and the operating current setting instruction according to the test combination that has not been tested includes: Classifying the untested test combinations according to the test combination of the most recent test to obtain N test combinations that meet the first setting rule; wherein N is a natural number, and the test combination that meets the first setting rule is a test combination in which the setting instruction of the device under test is consistent with the setting instruction of the device under test of the test combination of the most recent test; When there is at least one test combination that meets the first setting rule, updating the operating current setting instruction according to one of the test combinations that meets the first setting rule; When there is no test combination that meets the first setting rule, the device under test setting instruction and the operating current setting instruction are set according to one of the test combinations that has not been tested.

[0014] The technical solution of the present invention provides a device for testing the performance of arc extinguishing device in suppressing ground faults, which can test the performance of arc extinguishing device in suppressing ground faults under different working currents and different types of ground faults. It has the advantages of high testing efficiency and reliable accuracy, and is helpful to improve the safety of power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 is a circuit schematic diagram of a device for testing the performance of arc extinguishing device in suppressing ground fault in some embodiments of the present invention; Figure 2 is a schematic diagram of the structure of a fault model in some embodiments of the present invention; Figure 3 is a circuit structure block diagram of a control module and a wave recording device in some embodiments of the present invention; Figure 4 It is a program flow chart of a method for testing the performance of arc extinguishing device in suppressing ground fault in some embodiments of the present invention. DETAILED DESCRIPTION

[0016] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0017] It should be noted that the flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0018] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices. The present invention provides a device for testing the performance of arc extinguishing device in suppressing ground faults, which can test the performance of arc extinguishing device in suppressing ground faults under the condition of simulating the working condition of power system. Figure 1 As shown, the arc extinguishing device ground fault suppression performance test device, which can suppress the ground fault of the arc extinguishing device under the condition of simulating the working condition of the power system, may include a transformer 1, a first switch 2, a device access unit 3, a harmonic elimination unit 4, a working condition simulation unit 5, a fault simulation unit 6 and a data acquisition unit 7.

[0019] See also Figure 1 , the transformer 1 includes a low voltage side 11, a high voltage side 12 and a neutral point 13. Among them, the high voltage side 12 is used to output a high voltage three-phase power supply, and the voltage value of the high voltage three-phase power supply can be determined according to the power supply voltage output by the power system (referred to as the target power system) where the arc extinguishing device needs to be installed, such as the medium voltage power system outputting an AC voltage of 6.3KV. It should be noted that the low voltage side 11 includes three phase line input terminals, and the high voltage side 12 includes three phase line output terminals.

[0020] See also Figure 1 , the first end of the first switch 2 is electrically connected to the low-voltage side 11, and the second end of the first switch 2 is used to access the low-voltage input power supply, which can be a three-phase mains power supply or a three-phase power supply output by a three-phase generator. It can be understood that the transformer 1 can amplify the low-voltage input power supply based on the turns ratio, so as to output a high-voltage three-phase power supply for testing on the high-voltage side 12. In addition, the specific model of the transformer 1 can be adaptively configured. For example, when it is necessary to test the medium-voltage power system, an existing medium-voltage transformer can be used.

[0021] See also Figure 1 , the device access unit 3 is electrically connected to the neutral point 13, and the device access unit 3 is used to access at least one arc extinguishing device to be tested. The neutral point 13 corresponds to the common electrical connection point where the three phase line output ends of the high voltage side 12 are electrically connected in a star shape. Specifically, the device access unit 3 is used to access multiple arc extinguishing devices to be tested (such as Figure 1 The phase-controlled arc extinguishing coil A, the turn-adjustable arc extinguishing coil B and the controllable voltage source arc extinguishing device C are shown, and one of the arc extinguishing devices to be tested is controlled to be connected to the neutral point 13, so as to test the performance of the arc extinguishing device to be tested connected to the neutral point 13. It can be understood that under the action of the device access unit 3, after simulating the target power system working conditions, the device can control multiple arc extinguishing devices to be tested to be connected to the neutral point 13 in sequence, and then test the performance of multiple arc extinguishing devices to be tested in sequence, which is convenient for obtaining test data of different arc extinguishing devices to be tested under the same simulated working conditions, and also facilitates the comparison of test data, which helps to improve the test accuracy.

[0022] In some embodiments, Figure 1 As shown, the device access unit 3 may include a plurality of second switches 31, the first end of each second switch 31 is electrically connected to the neutral point 13, and the second end of each second switch 31 is used to connect to the arc extinguishing device to be tested. When a certain arc extinguishing device to be tested needs to be connected to the neutral point 13, the second switch 31 electrically connected to the arc extinguishing device to be tested is closed; when the arc extinguishing device to be tested does not need to be connected, the second switch 31 electrically connected to the arc extinguishing device to be tested is disconnected.

[0023] See also Figure 1 The detuning unit 4 is electrically connected to the high voltage side 12, and is used to eliminate the output harmonics of the high voltage side 12. In order to reduce the influence of harmonics in the power system, a detuning device is generally set on the output bus, and the detuning unit 4 is set to detun the high voltage three-phase power supply, so as to make the waveform of the high voltage three-phase power supply as close as possible to the actual output high voltage three-phase power supply of the target power system, thereby improving the test accuracy.

[0024] In some embodiments, Figure 1As shown, the detuning unit 4 may include a fifth switch 41, a first voltage transformer 42 and a detuning module 43. The primary side of the first voltage transformer 42 is electrically connected to the high voltage side 12 via the fifth switch 41, and the detuning module 43 is electrically connected to the secondary side of the first voltage transformer 42. Among them, the detuning module 43 may be an existing secondary detuning resistor or a microcomputer detuning device. In this embodiment, when the high voltage side 12 needs to be connected to the detuning module 43, the fifth switch 41 is controlled to be closed, so that the detuning module 43 can be coupled with the high voltage side 12 through the first voltage transformer 42, and then perform the detuning work. Since some power systems are not equipped with a detuning device, the detuning module 43 can be decoupled from the high voltage side 12 by controlling the fifth switch 41 to be disconnected.

[0025] In order to simulate the actual working condition of the target power system as much as possible, the detuning module 43 can be set to a detuning device with the same specifications and model as the detuning device installed on the target power system.

[0026] See also Figure 1 , the operating condition simulation unit 5 is electrically connected to the high voltage side 12, and the operating condition simulation unit 5 is used to simulate the output of various output currents of different sizes by the high voltage side 12 when the transformer 1 is working. In order to achieve standardized comparison of the performance of different arc extinguishing devices to be tested, the output current can take multiple current values ​​with certain representativeness according to the target power system. Taking the medium voltage power system as an example, the various output currents can include 6A (corresponding to the current output when the medium voltage power system is lightly loaded), 24A (corresponding to the current output when the medium voltage power system is heavily loaded) and 29A (corresponding to the current output when the medium voltage power system is fully loaded). Of course, the output current can also be set by the current of the actual operating condition of the target power system. In some embodiments, Figure 1 As shown, the working condition simulation unit 5 may include a plurality of third switches 51 and a plurality of three-phase capacitors 52. The first end of each third switch 51 is electrically connected to the high voltage side 12, and the first end of each three-phase capacitor 52 is electrically connected to the high voltage side 12 via the third switch 51 one by one, and the second end of each three-phase capacitor 52 is electrically connected to the ground at the same time. Among them, the capacitance values ​​of the plurality of three-phase capacitors 52 may include 1.7uF and 4.7uF. In this embodiment, since the high voltage three-phase power supply belongs to an AC signal, and the three-phase capacitor 52 has a capacitive reactance, after the third switch 51 is closed, the three-phase capacitor 52 electrically connected thereto is equivalent to a load connected in series between the high voltage three-phase power supply and the ground, that is, each three-phase capacitor 52 can be equivalent to a load. It can be understood that the number of three-phase capacitors 52 connected can be controlled by controlling the closing or disconnection of the plurality of third switches 51, thereby controlling the output current of the high voltage side 12.

[0027] Further, when the target power system is a medium voltage power system, accordingly, the number of the third switch 51 and the three-phase capacitor 52 can be 3, and the capacitance values ​​of the three three-phase capacitors 52 are 1.7uF, 1.7uF and 4.7uF respectively. When the output current needs to be set to 6A, one of the 1.7uF three-phase capacitors 52 is controlled to be connected to the high-voltage side 12; when the output current needs to be set to 24A, one of the 1.7uF three-phase capacitors 52 and the 4.7uF three-phase capacitor 52 are controlled to be connected to the high-voltage side 12; when the output current needs to be set to 29A, all three-phase capacitors 52 are controlled to be connected to the high-voltage side 12.

[0028] In some embodiments, Figure 1 As shown, each three-phase capacitor 52 may include three capacitors with the same capacitance, and the three capacitors are electrically connected to the three phase line output terminals of the high voltage side 12 one by one through the third switch.

[0029] Since the power system is working, multiple voltage transformers will be configured to cooperate with the monitoring system to monitor the real-time working conditions of the power system, and each transformer can be regarded as a load. In order to simulate the actual working conditions of the target power system more realistically, in some embodiments, the working condition simulation unit 5 can also include a number of sampling working condition simulation transformers, each of which is used to be set on the high-voltage side 12. Specifically, the sampling working condition simulation transformer can be an existing three-phase voltage transformer, and the sampling working condition simulation transformer can also choose whether to be put into use according to the actual working conditions of the target power system. Taking the target power system as the medium-voltage power system of a nuclear power plant as an example, when the medium-voltage power system is lightly loaded (i.e., outputting 6A output current), the medium-voltage power system will actually put into use 2 voltage transformers to monitor its voltage changes. For this, 2 sampling working condition simulation transformers can be put into use to realize working condition simulation. In order to further improve the simulation effect, the two put-in sampling working condition simulation transformers are preferably voltage transformers consistent with the voltage transformer model actually put into use by the medium-voltage power system under this working condition. When the medium-voltage power system is overloaded (i.e., outputting 24A output current), the medium-voltage power system will actually invest in 8 voltage transformers to monitor its voltage changes. For this purpose, 8 sampling working condition simulation transformers can be invested to realize working condition simulation. To further improve the simulation effect, the 8 sampling working condition simulation transformers invested are preferably voltage transformers of the same model as the voltage transformers actually invested in the medium-voltage power system under this working condition. When the medium-voltage power system is fully loaded (i.e., outputting 29A output current), the medium-voltage power system will actually invest in 10 voltage transformers to monitor its voltage changes. For this purpose, 10 sampling working condition simulation transformers can be invested to realize working condition simulation. To further improve the simulation effect, the 10 sampling working condition simulation transformers invested are preferably voltage transformers of the same model as the voltage transformers actually invested in the medium-voltage power system under this working condition.

[0030] See also Figure 1 The fault simulation unit 6 is electrically connected to one of the phases of the high voltage side 12, and the fault simulation unit 6 is used to simulate the occurrence of a ground fault. The types of ground faults include metal ground faults, resistance ground faults, and arc ground faults. Specifically, the fault simulation unit 6 may simulate multiple types of ground faults in one of the phase lines on the high voltage side, thereby more comprehensively testing the performance of the arc extinguishing device to be tested under different ground fault conditions.

[0031] In some embodiments, Figure 1 As shown, the fault simulation unit 6 may include a fourth switch 61 and a fault model 62. A first end of the fourth switch 61 is electrically connected to one phase of the high voltage side 12, and the fault model 62 is electrically connected between a second end of the fourth switch 61 and the ground. The fault model 62 is used to simulate a metal grounding fault, a resistance grounding fault, or an arc grounding fault.

[0032] In one embodiment, Figure 2 As shown, the fault model 62 may include a cable 6211, a cable connector 6212, a conductive metal 622, a resistor 623, an insulator 624, a cable connector support 625, and a cable support 626. The cable 6211 and the cable connector 6212 are detachably electrically connected and form a terminal block 621 after being electrically connected.

[0033] like Figure 2 As shown, the conductive metal 622 is electrically connected to the ground, and the terminal 621 is detachably electrically connected to the conductive metal 622. When the terminal 621 is electrically connected to the conductive metal 622 and the fourth switch 61 is closed, a metal grounding fault can be simulated.

[0034] like Figure 2 As shown, the resistor 623 is electrically connected to the ground, and the terminal 621 is detachably electrically connected to the resistor 623. When the terminal 621 is electrically connected to the resistor 623 and the fourth switch 61 is closed, a grounding fault through the resistor can be simulated. In addition, the resistor 623 is preferably a variable resistor, so that the variable resistor can be operated according to demand to adjust the size of the grounding resistance, thereby simulating more types of grounding fault conditions and improving the comprehensiveness of the test.

[0035] like Figure 2 As shown, the insulator 624 is placed on the ground, and the terminal 621 is detachably electrically connected to the insulator 624. When the terminal 621 is electrically connected to the insulator 624 and the fourth switch 61 is closed, an arc grounding fault of the insulator can be simulated. The insulator 624 is preferably an insulator of the same model as the insulator of the target power system.

[0036] like Figure 2As shown, the cable connector support 625 is placed on the ground, and the wiring head 621 is detachably electrically connected to the cable connector support 625, so that the wiring head 621 is exposed and a certain distance from the ground. When the wiring head 621 is electrically connected to the cable connector support 625 and the fourth switch 61 is closed, the occurrence of a cable connector arc grounding fault can be simulated. It should be noted that due to the different output voltages of different power systems, the minimum creepage distance is also different. Therefore, the cable connector support 625 makes the specific distance from the ground to which the wiring head 621 is exposed need to be set according to the actual situation. Furthermore, the support height of the cable connector support 625 can be adjusted by an insulating gasket.

[0037] like Figure 2 As shown, the cable support 626 is placed on the ground, and the cable 6211 can be inserted into the cable support 626, so that the core of the cable 6211 is exposed and a certain distance from the ground. When the cable 6211 can be inserted into the cable support 626 and the fourth switch 61 is closed, a cable arc grounding fault can be simulated. It should be noted that due to the different output voltages of different power systems, the minimum creepage distance is also different. Therefore, the specific distance between the core of the cable support 626 and the ground needs to be set according to the actual situation. Furthermore, the support height of the cable support 626 can be adjusted by an insulating gasket.

[0038] In another embodiment, the fault model 62 may also be an intelligent ground fault simulation cabinet of model XFUK-46.

[0039] See also Figure 1 The data acquisition unit 7 is electrically connected to the transformer 1, and is used to collect test data when simulating a ground fault. The test data includes at least one of the arc extinguishing device compensation current, the three-phase ground current of the detuning unit 4, the working current of the working condition simulation unit 5, the fault point current of the fault simulation unit 6, and the fault point voltage of the fault simulation unit 6.

[0040] Furthermore, if Figure 1 As shown, the data acquisition unit 7 may include a first current transformer 71 , a second current transformer 72 , a third current transformer 73 , a fourth current transformer 74 , a second voltage transformer 75 and a third voltage transformer 76 .

[0041] The first current transformer 71 is mounted on the grounding cable of the arc extinguishing device to be tested and is coupled to the arc extinguishing device to be tested to measure the compensation current of the arc extinguishing device.

[0042] The second current transformer 72 is mounted on the primary side of the first voltage transformer 42 and coupled with the primary side of the first voltage transformer 42 to measure the three-phase to ground current of the detuning unit 4. The second current transformer 72 may be an existing three-phase current transformer, or may be composed of three current transformers to respectively collect the three-phase currents flowing through the primary side of the first voltage transformer 42.

[0043] The third current transformer 73 is mounted on the grounding cable of the three-phase capacitor 52 and coupled with the three-phase capacitor 52 to measure the working current. The third current transformer 73 can be an existing three-phase current transformer, or can be composed of three current transformers to respectively collect the three-phase currents flowing through the three-phase capacitor 52.

[0044] The fourth current transformer 74 is mounted on the grounding cable of the fault model 62 and coupled with the fault model 62 to measure the current at the fault point.

[0045] The second voltage transformer 75 is mounted on the grounding cable of the fault model 62 and coupled with the fault model 62 to measure the voltage at the fault point.

[0046] The third voltage transformer 76 is mounted on the grounding cable of the primary side of the first voltage transformer 42 and coupled to the neutral point of the primary side of the first voltage transformer 42 to measure the zero-sequence voltage of the primary side of the first voltage transformer 42 .

[0047] To facilitate staff observation, in some embodiments, such as Figure 3 As shown, the arc extinguishing device ground fault suppression performance test device can also include a recording device 8 (such as a recorder, oscilloscope, etc.), and the recording device 8 is electrically connected to the first current transformer 71, the second current transformer 72, the third current transformer 73, the fourth current transformer 74 and the second voltage transformer 75 included in the data acquisition unit 7 to obtain, record and display the test data, so that the staff can evaluate which arc extinguishing device to be tested has better performance by observing the display information of the recording device 8.

[0048] In some embodiments, Figure 3 As shown, the first switch 2, the third switch 51 and the fifth switch 41 are three-phase contactors, and the second switch 31 and the fourth switch 61 are single-phase contactors.

[0049] The present invention also provides a method for testing the performance of arc extinguishing device in suppressing ground faults. The method is applied to a control module 9, and the control module 9 can control the arc extinguishing device in suppressing ground faults provided in the embodiment of the present invention to automatically perform the test. Figure 4As shown, the arc extinguishing device ground fault suppression performance testing method may include step S1, step S2, step S3, step S4, step S5, step S6, step S7 and step S8.

[0050] Step S1 includes: setting the device under test setting instruction and the working current setting instruction according to a preset test list; wherein the test list includes multiple test combinations, and each test combination includes the corresponding device under test setting instruction, working current setting instruction and fault type setting instruction. In this step, the staff can set the test list by operating a human-computer interaction unit (such as a mouse, keyboard, touch screen, etc.).

[0051] Step S2 includes: outputting the device under test setting instruction to the device access unit 3, so that the corresponding arc extinguishing device under test is connected to the neutral point 13 of the transformer 1. In this step, the device under test setting instruction can control one of the second switches 31 to close, that is, the arc extinguishing device under test is electrically connected to the neutral point 13.

[0052] Step S3 includes: outputting a working current setting instruction to the working condition simulation unit 5, so that when the transformer 1 is working, its high voltage side 12 simulates and outputs a set working current. In this step, the working current setting instruction can control at least one of the third switches 51 to be closed, so that the corresponding three-phase capacitor 52 is connected to the high voltage side 12, and then the working current is set to a corresponding value.

[0053] Step S4 includes: controlling the first switch 2 to close. After the first switch 2 is closed, the transformer 1 is powered on and the high-voltage side 12 outputs a high-voltage three-phase power supply for testing.

[0054] Step S5 includes: after the first switch 2 is closed, collecting test data through the data collection unit 7 .

[0055] In order to avoid damage to the arc extinguishing device's ground fault suppression performance test device due to resonance on the high-voltage side 12 during the test, the step S6 may also include: collecting the zero-sequence voltage on the primary side of the first voltage transformer 42 through the third voltage transformer 76 in the data acquisition unit 7, and determining whether the zero-sequence voltage has set a voltage threshold (which may be 30V), and if so, immediately controlling the first switch 2 to disconnect to stop the test.

[0056] Step S6 includes: controlling the fault simulation unit 6 to work so that the fault simulation unit 6 simulates a ground fault. In this step, the staff needs to insert the terminal 621 into the conductive metal 622, the resistor 623, the insulator 624 or the cable terminal support 625 in advance, or insert the cable 6211 into the cable support 626, and then control the fourth switch 61 to be closed.

[0057] Since the test process is affected by external noise interference and the actual working conditions of the electronic components in the test device, there is a certain uncertainty in the test, and there is a probability that the collected test data is "waste data". In order to improve the fault tolerance of obtaining test data, in some embodiments, step S6 may include: controlling the fault simulation unit 6 to work, so that the fault simulation unit 6 simulates the occurrence of a set number of ground faults. Specifically, the control module 9 can periodically control the fourth switch 61 to close and open, so that the fault simulation unit 6 simulates the occurrence of multiple ground faults, for example, after each closing of the fourth switch 61, the fourth switch 61 is controlled to be opened at an interval of 30 seconds to 60 seconds, and after each opening of the fourth switch 61, the fourth switch 61 is controlled to be closed. The set number of times is not less than 5 times.

[0058] Furthermore, in order to simplify the test data and specifically obtain the test data changes before and after the ground fault, step S6 can also include: controlling the recording device 8 to record at least 10 cycles before and after the moment when the fault simulation unit simulates the occurrence of the ground fault, and recording at least 10 cycles before and after the moment when the ground fault disappears.

[0059] Step S7 includes: after collecting the test data, controlling the first switch 2 to disconnect, and determining whether there is a test combination that has not been tested in the test list. If so, setting the device under test setting instruction, the working current setting instruction and the fault type setting instruction according to the test combination that has not been tested, and returning to step S2, otherwise executing step S8.

[0060] It should be noted that the test parameters corresponding to each test combination are different, including the arc extinguishing device to be tested and / or the working current. It can be understood that the test data of different test combinations can be obtained by cyclically executing steps S1 to S7.

[0061] In order to improve the test efficiency, the step of setting the device under test setting instruction and the working current setting instruction according to the test combination that has not been tested in step S7 may include step S71, step S72 and step S73.

[0062] Step S71 includes: classifying the test combinations that have not been tested according to the test combination of the most recent test to obtain N test combinations that meet the first setting rule; wherein N is a natural number, and the test combination that meets the first setting rule is a test combination whose setting instructions for the device under test are consistent with the setting instructions for the device under test of the test combination of the most recent test. For example, the performance of the phase-controlled arc suppression coil A under a working current of 6A was tested most recently. If the test combination that has not been tested contains a test combination in which the device under test corresponding to the setting instructions for the device under test is the phase-controlled arc suppression coil A, and the working current setting instructions corresponding to the working current setting are 24A or 29A, then the test combination meets the first setting rule.

[0063] Step S72 includes: when there is at least one test combination that meets the first setting rule, updating the operating current setting instruction according to one of the test combinations that meets the first setting rule. In this step, since the device under test setting instruction of the test combination that meets the first setting rule is consistent with the device under test setting instruction of the test combination tested most recently, only the operating current setting instruction needs to be updated, that is, the device under test setting instruction remains unchanged, which can reduce the frequency of operating the second switch 31 and help extend the life of the second switch 31.

[0064] Further, in order to extend the service life of the third switch 51, the step of updating the working current setting instruction according to one of the test combinations that conform to the first setting rule in step S72 may also include: updating the working current setting instruction according to the test combination that conforms to the second setting rule among the N test combinations that conform to the first setting rule, wherein the test combination that conforms to the second setting rule is the test combination whose working current setting instruction corresponds to the smallest working current among the N test combinations that conform to the first setting rule. Taking two groups of test combinations that conform to the first setting rule as an example, if the working current setting instruction of the first test combination corresponds to a working current of 24A, and the working current setting instruction of the second test combination corresponds to a working current of 29A, then the working current setting instruction will be updated according to the first test combination first, so that the control module 9 can control one more third switch 51 to be closed to achieve working current adjustment (that is, all the third switches 51 that were originally closed remain closed). Accordingly, the step of setting the setting instruction of the device under test and the working current setting instruction according to the preset test list in step S1 may include: setting the setting instruction and the working current setting instruction of a test combination with the smallest working current according to the working current setting instruction of all the test combinations included in the test list.

[0065] Step S73 includes: when there is no test combination that meets the first setting rule, setting the device under test setting instruction and the working current setting instruction according to one of the test combinations that has not been tested.

[0066] In some embodiments, the step of setting the setting instruction of the device under test and the working current setting instruction according to one of the test combinations that have not been tested in step S73 may include: among all the test combinations that have not been tested, setting the setting instruction of the test combination with the smallest working current and the working current setting instruction according to the working current setting instruction.

[0067] In some embodiments, in order to ensure that the three-phase capacitor 52 is discharged as quickly as possible after each simulated ground fault ends (i.e., after the first switch 2 is disconnected) and does not affect the next simulation test, a discharge load (such as a resistor) can be connected in parallel at both ends of the three-phase capacitor 52 to achieve rapid discharge. Of course, the discharge load can be connected to the three-phase capacitor 52 through a contactor, and the control module 9 can control the on and off of the contactor.

[0068] Step S8 includes: generating test results based on all collected test data. The test results can be output to the human-computer interaction unit for staff to view.

[0069] In some embodiments, step S8 may include: calculating the performance parameters corresponding to each test combination based on all test data; wherein the performance parameters include arc detection sensitivity, compensation response time, residual current stabilization time and residual current at the fault point.

[0070] The arc detection sensitivity corresponds to the time required for the voltage at the fault point to drop from a stable high voltage state to close to 0V when simulating an arc grounding fault.

[0071] The compensation response time corresponds to the time difference between the peak moment of the fault point current and the peak moment of the arc extinguishing device compensation current. The peak moment refers to the time when the current signal reaches the peak value.

[0072] The residual current at the fault point corresponds to the current value after the fault point current stabilizes after the ground fault occurs. In addition, the stabilized current value of the fault point current can be determined in the following way: a fault point current curve is fitted according to the fault point current, and the slope change of the fault point current curve is analyzed. When the absolute value of the slope drops to less than a set value (which can be 0.05), the fault point current corresponding to that moment is determined as the stabilized current value.

[0073] The residual current stabilization time corresponds to the time required from the moment a ground fault occurs to the moment the current at the fault point stabilizes.

[0074] It should be noted that the three-phase to ground current of the detuning unit 4 is used to help the staff observe the waveform of the working current output by the high-voltage side 12 to determine whether the distortion of the current signal caused by the harmonics meets the test standard (that is, the current signal waveform of the target power system cannot be too different). The staff can adjust the detuning device based on this situation. For the working current of the working condition simulation unit 5 (corresponding to the working current actually output by the high-voltage side 12), the control module 9 can be based on whether the working current and the preset working current are within the preset error range (±3%). For example, when the preset working current is 6A, the working current actually output by the high-voltage side 12 needs to be within 5.82A to 6.18A before it is allowed to continue working.

[0075] It should be noted that in order to ensure the personal safety of staff and equipment, before executing the arc extinguishing device ground fault suppression performance test method, the grounding point of the high-voltage side 12 needs to be isolated from the grounding point of the low-voltage input power supply to avoid a short circuit between the power supply system ground and the high-voltage three-phase power supply.

[0076] The present invention also provides a control module, which may include a memory, a processor, and a computer program stored in the memory and executable on the processor. When executing the computer program, the processor may implement the arc extinguishing device ground fault suppression performance test method provided in an embodiment of the present invention.

[0077] In some embodiments, the control module may further include a switch driving module, the switch driving module is electrically connected to the first switch 2, each second switch 31, the third switch 51, the fourth switch 61 and the fifth switch 41, and the switch driving module is used to control the first to fifth switches to be closed or opened. Among them, the switch driving module can be an existing PLC controller, and the PLC controller can output a driving voltage value to select the driving coil of the first to fifth switches, thereby controlling the closing or opening of the corresponding switches. Of course, the first to fifth switches can also be controlled by manual operation.

[0078] It can be understood that the present invention can test the ground fault suppression performance of different arc extinguishing devices under different operating currents and different types of ground faults, has the advantages of high testing efficiency and reliability, and helps to improve the safety of the power system.

[0079] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0080] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0081] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0082] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A device for testing the performance of arc extinguishing device in suppressing ground fault, characterized in that: include: A transformer (1), comprising a low voltage side (11), a high voltage side (12) and a neutral point (13), wherein the high voltage side (12) is used to output a high voltage three-phase power supply; A first switch (2), a first end of which is electrically connected to the low-voltage side (11), and a second end of which is used to connect to a low-voltage input power supply; A device access unit (3), electrically connected to the neutral point (13), and used for accessing at least one arc extinguishing device to be tested; A harmonic elimination unit (4), electrically connected to the high voltage side (12), and used to eliminate output harmonics of the high voltage side (12); A working condition simulation unit (5) is electrically connected to the high voltage side (12) and is used to simulate the high voltage side (12) outputting a plurality of output currents when the transformer (1) is working; A fault simulation unit (6) is electrically connected to one phase of the high voltage side (12) and is used to simulate a ground fault, wherein the types of the ground fault include a metal ground fault, a resistor ground fault and an arc ground fault; A data acquisition unit (7) is electrically connected to the transformer (1) and is used to collect test data when simulating a ground fault, wherein the test data includes at least one of a compensation current of an arc extinguishing device, a working current flowing through the operating condition simulation unit (5), a fault point current of the fault simulation unit (6), and a fault point voltage of the fault simulation unit (6).

2. The arc extinguishing device ground fault suppression performance test device according to claim 1, characterized in that: The operating condition simulation unit (5) comprises: a plurality of third switches (51), wherein first ends of the third switches are electrically connected to the high voltage side (12); and A plurality of three-phase capacitors (52), wherein the first end of each of the three-phase capacitors (52) is electrically connected to the high voltage side (12) via the third switch (51) one by one, and the second end of each of the three-phase capacitors (52) is electrically connected and grounded at the same time.

3. The arc extinguishing device ground fault suppression performance test device according to claim 2, characterized in that: The operating condition simulation unit (5) further comprises: A plurality of sampling working condition simulation transformers are used to be installed on the high voltage side (12).

4. The arc extinguishing device ground fault suppression performance test device according to claim 2, characterized in that: The fault simulation unit (6) comprises: a fourth switch (61), a first end of which is electrically connected to one phase of the high voltage side (12); and A fault model (62) is electrically connected between the second end of the fourth switch (61) and the ground, and is used to simulate the occurrence of the metal grounding fault, the resistor grounding fault, or the arc grounding fault.

5. The arc extinguishing device ground fault suppression performance test device according to claim 4, characterized in that: The device access unit (3) comprises: A plurality of second switches (31), wherein the first ends of the second switches are electrically connected to the neutral point (13), and the second ends of the second switches are used to be connected to the arc extinguishing device to be tested.

6. The arc extinguishing device ground fault suppression performance test device according to claim 5, characterized in that: The detuning unit (4) comprises: Fifth switch (41); A first voltage transformer (42), a primary side of which is electrically connected to the high voltage side (12) via the fifth switch (41); and The detuning module (43) is electrically connected to the secondary side of the first voltage transformer (42).

7. The arc extinguishing device ground fault suppression performance test device according to claim 6, characterized in that: The data acquisition unit (7) comprises: A first current transformer (71), coupled to the arc extinguishing device to be tested, to measure a compensation current of the arc extinguishing device; A second current transformer (72) coupled to the primary side of the first voltage transformer (42) to measure the three-phase current to ground on the primary side of the detuning unit (4); A third current transformer (73) coupled to the three-phase capacitor (52) to measure the operating current; a fourth current transformer (74), coupled to the fault model (62) to measure the fault point current; and A second voltage transformer (75) is coupled to the fault model (62) to measure the fault point voltage.

8. A method for testing the performance of arc extinguishing device in suppressing ground fault, characterized in that: The arc extinguishing device ground fault suppression performance testing device according to any one of claims 1 to 7, the testing method comprising: S1. Setting a device under test setting instruction and a working current setting instruction according to a preset test list, wherein the test list includes a plurality of test combinations, and each of the test combinations includes a corresponding device under test setting instruction and a working current setting instruction; S2, outputting the setting instruction of the device to be tested to the device access unit (3), so that the corresponding arc extinguishing device to be tested is connected to the neutral point (13) of the transformer (1); S3, outputting the working current setting instruction to the working condition simulation unit (5), so that when the transformer (1) is working, its high voltage side (12) simulates and outputs the set working current; S4, controlling the first switch (2) to close; S5, after the first switch (2) is closed, collecting test data through the data collection unit (7); S6, controlling the fault simulation unit (6) to operate so that the fault simulation unit (6) simulates the occurrence of a ground fault; S7, after collecting the test data, controlling the first switch (2) to be disconnected, and determining whether there is a test combination that has not been tested in the test list, if so, setting the device under test setting instruction and the working current setting instruction according to the test combination that has not been tested, and returning to S2, otherwise executing S8; S8. Generate test results based on all collected test data.

9. The arc extinguishing device ground fault suppression performance testing method according to claim 8, characterized in that: The S8 includes: The performance parameters corresponding to each test combination are calculated based on all the test data; wherein the performance parameters include arc detection sensitivity, compensation response time, residual current stabilization time and residual current at the fault point.

10. The arc extinguishing device ground fault suppression performance testing method according to claim 9, characterized in that: In the step S7, the step of setting the device under test setting instruction and the operating current setting instruction according to the test combination that has not been tested includes: Classifying the untested test combinations according to the test combination of the most recent test to obtain N test combinations that meet the first setting rule; wherein N is a natural number, and the test combination that meets the first setting rule is a test combination in which the setting instruction of the device under test is consistent with the setting instruction of the device under test of the test combination of the most recent test; When there is at least one test combination that meets the first setting rule, updating the operating current setting instruction according to one of the test combinations that meets the first setting rule; When there is no test combination that meets the first setting rule, the device under test setting instruction and the operating current setting instruction are set according to one of the test combinations that has not been tested.

Images