Safety level evaluation test method for high voltage current limiting fuses in nuclear power plants

Abstract

The present invention discloses a safety level certification test method for high-voltage current-limiting fuses in nuclear power plants. The method comprises: conducting a protection coordination test to obtain coordination test results of the fuse under test in combination with a preset test device and executing multiple test items; then, conducting a seismic resistance test to obtain seismic resistance test results of the fuse under test performing its electrical safety function under set test conditions during an operating reference earthquake and a safety shutdown earthquake. The implementation of the present invention can verify the actual performance of the fuse under test when combined with the preset test device, as well as the impact of a vibration accident on the performance of the fuse under test.

Description

Technical Field

[0001] The present invention relates to the field of high-voltage current-limiting fuses, and in particular to a safety level identification test method for high-voltage current-limiting fuses in nuclear power plants. Background Art

[0002] High-voltage current-limiting fuses are crucial for ensuring the safety of power distribution systems in nuclear power plants. While fuses are currently screened based on nuclear power standards, the relevant technical qualification testing procedures suffer from incompleteness, substandard standards, and lack of standardization. In particular, these procedures neglect actual performance testing of fuses in conjunction with components, as well as the impact of vibration on fuse performance. This increases the likelihood of safety incidents caused by fuse failures in nuclear power plants and reduces the safety of power distribution systems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a safety level identification test method for high-voltage current-limiting fuses in nuclear power plants.

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct a safety level identification test method for high-voltage current-limiting fuses in nuclear power plants, comprising:

[0005] Conduct protection coordination tests to obtain coordination test results of multiple test items after combining the fuse under test with the preset test device;

[0006] Then, a seismic test is performed to obtain seismic test results of the fuse to be tested performing the electrical safety function under set test conditions during an operating reference earthquake and a safe shutdown earthquake.

[0007] Preferably, the preset test device includes a protection device, a contactor unit, and a test socket for connecting to the fuse to be tested; the first end of the test socket is connected to the expected current, and the second end of the test socket is connected to the contactor unit; the protection device is connected to the contactor unit and controls the contactor unit to be closed or turned off according to the current signal flowing through the fuse to be tested;

[0008] Each of the test items includes:

[0009] Setting the low protection threshold, low protection threshold response time, high protection threshold and high protection threshold response time of the protection device, as well as the expected current according to the test project requirements;

[0010] Perform the following test N times: setting the initial state of the contactor unit according to the test mode, then inputting the expected current into the fuse to be tested until the contactor or protective device is actuated, and recording the state of the fuse to be tested as the result of this test; wherein the test mode is a closing test or an opening test;

[0011] If any test result fails, the corresponding test item is judged to be unqualified.

[0012] Preferably, the preset test device further includes a generator, a switch control unit, a frequency modulation unit for adjusting the frequency of the expected current, a reactance adjustment unit for adjusting the reactance of the test circuit, a capacitance adjustment unit for adjusting the capacitance of the test circuit, a current measurement unit for measuring the expected current, and a voltage measurement unit for measuring the test voltage of the expected current;

[0013] The output end of the generator is connected to the first end of the test socket via the switch control unit and the reactance adjustment unit, the voltage measuring unit and the current measuring unit are connected to the first end of the test socket, and the first end of the test socket is further connected to the ground via the frequency modulation unit and the capacitance adjustment unit respectively.

[0014] Preferably, the seismic test includes:

[0015] The fuse to be tested is combined with a contactor and fixed to a seismic simulation device, and artificial seismic waves are generated by the seismic simulation device based on a set vibration response spectrum, so that the fuse to be tested performs at least one operating baseline seismic test and a safety shutdown seismic test to obtain a vibration response spectrum;

[0016] During the operation benchmark earthquake test and the safety shutdown earthquake test, a constant current load test is also performed to obtain a current waveform flowing through the fuse under test during the earthquake test;

[0017] Then, judging the legitimacy of each earthquake test based on the set vibration response spectrum, vibration response spectrum and flowing current waveform;

[0018] If all the earthquake tests are legal, a post-earthquake detection test is performed on the fuse to be tested to obtain and determine whether the earthquake resistance test is qualified based on the verification data.

[0019] Preferably, the post-earthquake detection test includes appearance and dimension inspection, temperature rise test, insulation test, tolerance test and waterproof test.

[0020] Preferably, the seismic test further includes:

[0021] After the fuse to be tested is assembled with the contactor and fixed on the earthquake simulation device, a vibration response check is also performed to detect whether the fuse to be tested has a dangerous frequency;

[0022] If a dangerous frequency exists, the seismic test is stopped.

[0023] Preferably, the vibration response check includes:

[0024] The fuse to be tested is excited from three axis directions of a three-dimensional coordinate system using a preset white noise and lasts for a set time to detect whether the resonant frequency of the fuse to be tested is within a set range. If so, it is determined that the fuse to be tested has a dangerous frequency.

[0025] Preferably, the seismic test further includes:

[0026] Before performing the operation benchmark earthquake test and the safety shutdown earthquake test, performing DC resistance measurement and X-ray inspection on the fuse to be tested to obtain reference data;

[0027] After completing the operation benchmark earthquake test and the safety shutdown earthquake test, the DC resistance measurement and X-ray detection of the fuse to be tested are performed again to obtain post-test data, and then the qualification of the earthquake resistance test is judged based on the reference data and the post-test data.

[0028] Preferably, before performing the seismic test, the method further comprises:

[0029] Conduct fuse type tests to obtain the specification parameter evaluation results of the fuse to be tested;

[0030] Conduct temperature rise test on combination electrical appliances to obtain the test results;

[0031] A durability test is performed to obtain a durability test result of the fuse to be tested that changes with time due to degradation during normal operation.

[0032] Preferably, the fuse type test includes: appearance and dimension inspection, DC resistance measurement, breaking test, pre-arcing time current characteristic test, temperature rise test, striker test, insulation test, withstand test and waterproof test.

[0033] The implementation of the technical solution of the present invention can verify the actual performance of the fuse to be tested after being matched with the preset test device, and verify the impact of the vibration accident on the performance of the fuse to be tested by running the benchmark earthquake and the safe shutdown earthquake. It can provide an important reference for the subsequent safety level identification test of the high-voltage current-limiting fuse, help to achieve a more comprehensive and safety-level identification test of the fuse, reduce the failure rate of the fuse, and play a positive role in maintaining the safe operation of the distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0035] Figure 1 It is a flow chart of a safety level evaluation test method for a high-voltage current-limiting fuse in a nuclear power plant in some embodiments of the present invention;

[0036] Figure 2 and Figure 3 is a schematic structural diagram of a preset test device in some embodiments of the present invention;

[0037] Figure 4 is a schematic structural diagram of an earthquake simulation device in some embodiments of the present invention;

[0038] Figure 5 is a test circuit structure diagram of a constant current load test in some embodiments of the present invention;

[0039] Figure 6 is a schematic diagram of setting a vibration response spectrum by a vibration response spectrum envelope in the Y-axis direction in some embodiments of the present invention;

[0040] Figure 7 It is a flow chart of a safety level identification test method for a high-voltage current-limiting fuse in a nuclear power plant in other embodiments of the present invention. DETAILED DESCRIPTION

[0041] 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.

[0042] It should be noted that the flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all content and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0043] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0044] See also Figure 1 , is a flow chart of a safety level evaluation test method for a nuclear power plant high-voltage current-limiting fuse in some embodiments of the present invention, the method comprising:

[0045] Conduct protection coordination tests to obtain coordination test results of multiple test items after combining the fuse under test with the preset test device;

[0046] Then, a seismic test is performed to obtain seismic test results of the fuse to be tested performing the electrical safety function under set test conditions during the operating reference earthquake and the safe shutdown earthquake.

[0047] The implementation of the technical solution of the present invention can verify the actual performance of the fuse to be tested after being matched with the preset test device, and verify the impact of the vibration accident on the performance of the fuse to be tested by running the benchmark earthquake and the safe shutdown earthquake. It can provide an important reference for the subsequent safety level identification test of the high-voltage current-limiting fuse, help to achieve a more comprehensive and safety-level identification test of the fuse, reduce the failure rate of the fuse, and play a positive role in maintaining the safe operation of the distribution system.

[0048] In some embodiments, as Figure 2 As shown, the preset test device includes a protection device 1, a contactor unit 2 and a test socket 3 for connecting to the fuse to be tested; the first end of the test socket 3 is connected to the expected current, and the second end of the test socket 3 is connected to the contactor unit 2; the protection device 1 is connected to the contactor unit 2, and controls the contactor unit 2 to be turned off or closed according to the current signal flowing through the fuse to be tested.

[0049] Since there are a large number of loads powered by three-phase power in nuclear power plants, in order to make the expected current the same or similar to the power signal of the fuse when it is working on site, in some embodiments, the expected current is a three-phase AC signal, the contactor unit 2 includes a three-phase contactor, and the test socket 3 includes three fuse sockets. In this way, each time a test project is performed, not only can three fuses to be tested be tested at the same time, but the power signal of the fuse when it is working on site can also be simulated as much as possible, which is conducive to improving the accuracy of the test.

[0050] In some embodiments, the protection device 1 (not shown) can be a control device such as an industrial computer. In addition, the preset test device also includes three current transformers CT for collecting the current signal size on each fuse circuit to be tested. The protection device 1 is connected to the control end of each contactor to obtain the current signal on each fuse circuit to be tested through the three current transformers CT, thereby monitoring in real time and controlling the corresponding contactor to be turned off or closed according to the current size of each circuit. In addition, the connection relationship between the various components in the preset test device can be referred to Figure 2 .

[0051] Furthermore, in some embodiments, each test item includes: setting the low protection threshold, low protection threshold response time, high protection threshold and high protection threshold response time, and the size of the expected current of the protection device 1 according to the test item requirements; performing the following test N times: setting the initial state of the contactor unit 2 according to the test method, and then inputting the expected current into the fuse to be tested until the contactor or protection device 1 is actuated, and recording the state of the fuse to be tested as the result of this test; wherein the test method is a closing test or an opening test; if any test result fails, the corresponding test item is determined to be unqualified.

[0052] The various test items in the protection coordination test can be referred to Table 1.

[0053]

[0054] Table 1

[0055] Among them, CO represents the closing test, that is, the contactor is open before the test item starts, and the contactor is closed after the test item starts. O represents the opening test, that is, the contactor is closed before the test item starts. IR is the current value when the fuse under test is loaded with the maximum load (such as a motor). F1 is the current value corresponding to the pre-arcing time of the fuse under test for 10S. I is the maximum arc current of the fuse under test. F2 It is the current value corresponding to the pre-arcing time of the fuse for 1S. F3 I is the current value corresponding to the pre-arcing time of the fuse to be tested of 0.1S. MC It is the maximum breaking current of the fuse. N is the rated current of the contactor and the fuse to be tested. MIN The minimum protection threshold response time pre-designed for protection device 1. MP is the maximum protection threshold pre-designed for protection device 1. T1 is the low protection threshold response time. K1 is the low protection threshold. T2 is the high protection threshold response time. K2 is the high protection threshold.

[0056] Specifically, each test item can also be divided into three test series, A, B, and C, based on the test purpose. Series A includes tests carried out when the expected current is a variety of situations that may occur during normal operation after the combination of the contactor and the fuse to be tested is combined; Series B includes tests carried out when the expected current is the current value at different moments of the pre-arcing time; and Series C includes tests carried out when the expected current is different proportions of breaking current.

[0057] When conducting a test project, the tester can prepare for the test by looking up Table 1. Taking Project 1 as an example, by looking up the "Test Series" column, it is determined that the number of tests N is 3, and then the following test is repeated 3 times:

[0058] First, set the test voltage to Um (Um is generally 6.6KV), and set the low protection threshold of the protection device 1 to 1.2I N , the low protection threshold response time is set to 10s, the high protection threshold is set to I MP and the high protection threshold response time is set to 1s; then, by checking the test series column, it is found that the test mode is CO, so that the initial state of each contactor in the contactor unit 2 is set to open; then, after the expected current is ready, each contactor is closed and maintained for a certain time (not less than the low protection threshold response time); the protection device 1 monitors the current signal on each fuse circuit to be tested in real time through the current transformer CT. If the flowing current is greater than the low protection threshold for more than 10s or the current is greater than the high protection threshold for more than 1s, the protection device 1 will control the corresponding contactor to open; finally, check whether each fuse is activated. If all fuses do not activate (that is, the result corresponding to the "Whether the fuse is activated" column of item 1 is consistent), then the test is judged to be qualified, otherwise the test is judged to be unqualified. As long as at least one test result fails in the three repeated tests, the test result of item 1 is judged to be unqualified.

[0059] It should be noted that the test results of each test item constitute the coordinated test results.

[0060] In some embodiments, such as Figure 3 As shown, the preset test device also includes a generator 4, a switch control unit 5, a frequency modulation unit 6 for adjusting the frequency of the expected current, a reactance adjustment unit 7 for adjusting the reactance of the test circuit, a capacitance adjustment unit 8 for adjusting the capacitance of the test circuit, a current measuring unit 9 for measuring the expected current, and a voltage measuring unit 10 for measuring the test voltage of the expected current; the output end of the generator 4 is connected to the first end of the test socket 3 via the switch control unit 5 and the reactance adjustment unit 7, the voltage measuring unit 10 and the current measuring unit 9 are connected to the first end of the test socket 3, and the first end of the test socket 3 is also connected to the ground via the frequency modulation unit 6 and the capacitance adjustment unit 8, respectively.

[0061] Specifically, the generator 4 can be a short-circuit generator, and the size of the three-phase voltage output can be adjusted according to demand. The switch control unit 5 includes three each of a protection switch GB, a closing switch MS and an operating switch MB. The protection switch GB, the closing switch MS and the operating switch MB cooperate to protect and control the output voltage circuit of each phase of the generator 4. The reactance adjustment unit 7 includes three adjustable inductors, which are used to adjust the reactance value of the output voltage circuit of each phase of the generator 4, thereby adjusting the expected current size. The capacitance adjustment unit 8 includes several capacitors. The current measuring unit 9 can be an ammeter or a current transformer. The voltage measuring unit 10 can be a voltmeter or a voltage transformer. The specific connection structure of the generator 4, the switch control unit 5, the frequency modulation unit 6, the reactance adjustment unit 7, the capacitance adjustment unit 8, the current measuring unit 9 and the voltage measuring unit 10 can be referred to. Figure 3 .

[0062] In this embodiment, the expected current size can be set by adjusting the reactance through the cooperation of the reactance adjustment unit 7 and the current measurement unit 9; the test personnel can also use the capacitance adjustment unit 8 to adjust the capacitance of the test circuit, and adjust the frequency of the expected current through the frequency modulation unit 6, so as to simulate the circuit environment of the fuse to be tested when working in the actual application scenario as much as possible, which helps to improve the test accuracy; and the generator 4 cooperates with the voltage measurement unit 10 to ensure the accuracy of the test voltage.

[0063] In some embodiments, the seismic test includes: combining a fuse to be tested with a contactor and fixing the combined device to a seismic simulation device; generating artificial seismic waves through the seismic simulation device based on a set vibration response spectrum; and causing the fuse to be tested to perform at least one operating baseline seismic test and a safety shutdown seismic test to obtain a vibration response spectrum.

[0064] During the operation benchmark earthquake test and the safety shutdown earthquake test, a constant current load test is also carried out to obtain the current waveform flowing through the fuse under test during the earthquake test;

[0065] Then, the legitimacy of each earthquake test is judged based on the set vibration response spectrum, vibration response spectrum and flowing current waveform;

[0066] If all earthquake tests (including the operating benchmark earthquake test and the safe shutdown earthquake test) are legal, a post-earthquake detection test will be carried out on the fuse to be tested to obtain and determine whether the earthquake resistance test is qualified based on the verification data.

[0067] like Figure 4As shown, the earthquake simulation device is equipped with six acceleration measurement points, namely A1, A2, A3, A4, A5, and A6. Each measurement point measures vibration acceleration in the X, Y, and Z directions. Using common algorithms in the prior art, the vibration accelerations collected at each measurement point are synthesized to obtain a vibration response spectrum. It should be noted that the function of the earthquake simulation device is to simulate earthquakes and can be any earthquake simulation device or apparatus in the prior art, which is not limited here.

[0068] An operation benchmark earthquake test simulates an operation benchmark earthquake. A safety shutdown earthquake test simulates a safety shutdown earthquake. The vibration response spectrum is used to control the earthquake simulation equipment to generate artificial seismic waves similar to an operation benchmark earthquake or a safety shutdown earthquake, thereby simulating the occurrence of an operation benchmark earthquake or a safety shutdown earthquake. Furthermore, the vibration response spectrum serves as a vibration characteristic standard for operation benchmark and safety shutdown earthquake tests. The vibration response spectrum reflects the vibration characteristics of the operation benchmark and safety shutdown earthquake tests.

[0069] In some embodiments, as Figure 5 As shown in Figure 1, the constant current load test involves inputting a constant current into the fuse under test via an adjustable constant current power supply, and using an oscilloscope to collect and record the current waveform (i.e., the current waveform) flowing through the fuse under test during the earthquake test. As can be easily understood, the current waveform can be used to characterize the continuity of the current flowing through the fuse under test during each earthquake test.

[0070] In some embodiments, the legality of each earthquake test can be judged according to the set vibration response spectrum, vibration response spectrum and circulating current waveform in the following manner: judging whether the vibration response spectrum envelops the set vibration response spectrum, and judging whether the circulating current of the fuse to be tested in the earthquake test is continuous according to the circulating current waveform; if the vibration response spectrum envelops the set vibration response spectrum and the circulating current is continuous, then the corresponding earthquake test is judged to be legal; otherwise, the earthquake test is judged to be unqualified.

[0071] The vibration response spectrum envelope sets the vibration response spectrum. In the Y direction and at the same frequency, the acceleration generated during the earthquake test is no less than the acceleration corresponding to the set vibration response spectrum. The vibration intensity of the earthquake test is sufficient, that is, the vibration severity of the earthquake test is no less severe than the standard operating benchmark earthquake or safety shutdown earthquake. In some embodiments, the vibration response spectrum envelope in the Y direction sets the vibration response spectrum as shown in the figure below. Figure 6 As shown in the figure, the vertical axis represents acceleration and the horizontal axis represents frequency. The upper graph is the vibration response spectrum in the Y direction, and the lower graph corresponds to the set vibration response spectrum in the Y direction.

[0072] The continuity of the current flowing through the fuse under test during the earthquake test can be reflected in the vibration process, and the electrical connection between the fuse and the contactor is stable and reliable.

[0073] It is understandable that the purpose of judging whether each earthquake test is qualified is to ensure that each operation benchmark earthquake test and safety shutdown earthquake test is in compliance with the standards, making the collected vibration response spectrum more credible, thereby improving the accuracy of the vibration test.

[0074] In some embodiments, the damping ratio of the artificial seismic wave may be 5%.

[0075] In some embodiments, during the seismic test, the operational baseline seismic test is performed five times, and the safety shutdown seismic test is performed one time. Accordingly, the set vibration response spectrum can be formed by combining the standard vibration response spectra corresponding to the five operational baseline seismic tests and the standard vibration response spectrum corresponding to the one safety shutdown seismic test.

[0076] In some embodiments, the post-earthquake inspection test includes appearance and dimension inspection, temperature rise test, insulation test, withstand test and waterproof test.

[0077] In some embodiments, the appearance and size inspection includes inspecting the appearance and mechanical structure of the fuse to be tested, including checking whether the fuse's contacts, clips and other components are loose or deformed, so as to verify whether the fuse after each earthquake test (hereinafter referred to as the post-earthquake fuse) has structural damage. If no structural damage occurs, the appearance and size inspection of the post-earthquake fuse is determined to be qualified.

[0078] In some embodiments, the temperature rise test includes setting a test current to the fuse to be tested to collect and determine whether the temperature rise of the set components in the fuse to be tested meets the standard. If the temperature rise of each set component meets the standard, the temperature rise test of the post-earthquake fuse is determined to be qualified.

[0079] In some embodiments, the insulation test includes performing a lightning impulse voltage dry test and a power frequency voltage test on the post-earthquake fuse. If both the lightning impulse voltage dry test and the power frequency voltage test are qualified, the insulation test of the post-earthquake fuse is determined to be qualified.

[0080] In some embodiments, the withstand test includes continuously inputting N (which can be 20 times) pulse currents with a set period (which can be 10 minutes) into the fuse to be tested. If the post-earthquake fuse can operate normally, it is determined that the withstand test of the post-earthquake fuse has passed.

[0081] In some embodiments, the waterproof test includes immersing the fuse to be tested in water at a set temperature (which can be 70°C to 80°C) for a certain period of time (which can be 5 minutes), and judging whether bubbles are generated during the entire process. If no bubbles are generated, it is determined that the waterproof test of the post-earthquake fuse has passed.

[0082] In some embodiments, the seismic test also includes: after the fuse to be tested is combined with the contactor and fixed on the earthquake simulation equipment (that is, before each earthquake test is performed), a vibration response check is also performed to detect whether the fuse to be tested has a dangerous frequency; if a dangerous frequency exists, the seismic test is stopped.

[0083] Furthermore, in some embodiments, the vibration response check includes: using preset white noise to excite the fuse to be tested from three axis directions of the three-dimensional coordinate system, and continuing for a set time to detect whether the resonant frequency of the fuse to be tested is within a set range. If so, it is determined that the fuse to be tested has a dangerous frequency.

[0084] In this embodiment, the purpose of detecting whether the fuse under test has a dangerous frequency is to prevent resonance in the fuse during an actual operating benchmark earthquake or a safety shutdown earthquake. This could cause the fuse to fail due to unexpected vibration intensification, potentially impacting the safe operation of the nuclear power plant. Furthermore, if subsequent seismic tests are performed after the fuse under test has been detected to have a dangerous frequency, the test fuse would likely resonate with the vibration, reducing the reference value of the seismic test. Therefore, if the fuse under test is determined to have a dangerous frequency, the seismic test can be terminated.

[0085] Furthermore, in some embodiments, after determining that a dangerous frequency exists in the fuse to be tested, the safety level identification test method for the high-voltage current-limiting fuse of the nuclear power plant also includes: adjusting the vibration damping of the combination of the fuse to be tested and the contactor (such as adding a vibration damper), and continuing to perform the seismic test after ensuring that the fuse to be tested does not have a dangerous frequency within the set range.

[0086] In some embodiments, the frequency and setting range of the preset white noise can be 0.5 to 100 Hz, the acceleration peak of the preset white noise can be 0.1 g (g represents 1 unit of gravity acceleration), and the setting time can be 110 to 130 seconds.

[0087] In some embodiments, the seismic test also includes: before conducting the operating benchmark seismic test and the safe shutdown seismic test, performing DC resistance measurement and X-ray detection on the fuse to be tested to obtain reference data; after completing the operating benchmark seismic test and the safe shutdown seismic test, performing DC resistance measurement and X-ray detection on the fuse to be tested again to obtain post-test data, and then judging whether the seismic test is qualified based on the reference data and the post-test data.

[0088] DC resistance measurement involves measuring the DC resistance of the fuse under test using conventional DC resistance measurement equipment. X-ray inspection involves using X-rays to examine the fuse's internal morphology, including whether it is desoldering or broken, to determine whether the fuse's distribution is normal. Pre-earthquake X-ray inspection data is then generated based on the results.

[0089] Before conducting the operating benchmark earthquake test and the safe shutdown earthquake test, the DC resistance measurement and X-ray detection are carried out to obtain the pre-earthquake DC resistance value and the pre-earthquake X-ray detection data, thereby forming the reference data; after completing the operating benchmark earthquake test and the safe shutdown earthquake test, the DC resistance measurement and X-ray detection are carried out again to obtain the post-earthquake DC resistance value and the post-earthquake X-ray detection data, thereby forming the post-test data; in this way, the pre-earthquake DC resistance value and the post-earthquake DC resistance value can be used to determine whether the DC resistance value of the fuse to be tested is within the set standard range before and after the earthquake test, and the pre-earthquake X-ray detection data and the post-earthquake X-ray detection data can be used to determine whether the distribution state of the fuse before and after the earthquake test is normal. If the DC resistance value and the melt distribution state of the fuse to be tested before and after the earthquake test are normal, the earthquake resistance test is determined to be qualified.

[0090] In some embodiments, as Figure 7 As shown, before the seismic test, the following tests are also carried out: fuse type test, combination electrical temperature rise test and durability test.

[0091] Among them, conducting fuse type tests can obtain the standard parameter evaluation results of the fuse to be tested.

[0092] Furthermore, in some embodiments, the fuse type test includes the following tests: appearance and dimensions inspection, DC resistance measurement, breaking test, pre-arcing time and current characteristics test, temperature rise test, striker test, insulation test, withstand test, and waterproof test. Furthermore, if any test result fails during the fuse type test, the specification parameter evaluation result is deemed unqualified.

[0093] It should be noted that in this implementation, the appearance and dimension inspection, DC resistance measurement, temperature rise test, insulation test, withstand test and waterproof test are performed in the same manner as described above. These tests are repeated because some tests in the protection coordination test and seismic test will cause aging and a certain degree of damage to the fuse under test. Therefore, it is necessary to strictly monitor some performance characteristics of the fuse under test (corresponding to the parameter objects tested in the above tests) to ensure the accuracy of the identification test results.

[0094] The breaking test is one of the important indicators for verifying the breaking performance of high-voltage current-limiting fuses. It includes breaking test method A, breaking test method B, and breaking test method C. Breaking test method A verifies whether the fuse under test can normally break when the maximum short-circuit current is input. Breaking test method B verifies whether the fuse under test can normally break when the maximum arc energy current is input. Breaking test method C verifies whether the backup fuse in the fuse under test can normally break when the rated minimum breaking current is input.

[0095] The striker test involves inputting a relatively low current or voltage value into the fuse under test to determine whether the striker in the fuse under test can release energy sufficient to operate normally under this operating environment.

[0096] The temperature rise test results of the combination electrical appliances can be obtained by conducting the temperature rise test of the combination electrical appliances.

[0097] In some embodiments, the temperature rise test of the combination electrical appliance includes combining the fuse to be tested with the contactor and then performing a temperature rise test to obtain temperature rise data of the combination of the fuse to be tested and the contactor during continuous normal operation. If the temperature rise of a certain set component does not meet the standard, the temperature rise test result of the combination electrical appliance is determined to be unqualified.

[0098] The durability test can obtain the durability test results of the fuse under test that change with time due to degradation during normal operation.

[0099] In some embodiments, the durability test includes at least one of a fuse box robustness test, a striker mechanism test, and a combination electrical appliance tolerance test. In addition, if any of the above test results are unqualified, the durability test result is determined to be unqualified.

[0100] The fuse box robustness test involves plugging and unplugging the fuse box in the fuse under test multiple times (generally not less than 100 times), and verifying whether the plugging and unplugging operation causes obvious damage to the appearance of the fuse under test. If so, the fuse box robustness test is judged to have failed.

[0101] The striker mechanism test involves repeatedly inputting a set energy into the striker, causing it to collide with the indicator or release, and verifying whether it can trip normally. This verifies whether the striker's mechanical reliability meets the requirements. If the mechanical reliability of the striker meets the requirements, the striker mechanism test is considered to have passed. Specifically, the striker is input with a minimum impact energy of no less than 30 times and a maximum impact energy of no more than 10 times to verify its normal operation.

[0102] The combination electrical appliance withstand test includes combining the fuse to be tested with the contactor and then performing a withstand test. If the fuse to be tested can operate normally, the combination electrical appliance withstand test is judged to be qualified.

[0103] It should be noted that as long as any of the test results in the protection coordination test, fuse type test, combination electrical temperature rise test, durability test and seismic resistance test fail, the fuse under test will be judged as not meeting the safety level requirements.

[0104] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0105] 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 above description has generally described the components and steps of each example according to their functions. 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 beyond the scope of the present invention.

[0106] The steps of the methods or algorithms 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), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0107] It is understandable that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A safety level identification test method for high-voltage current-limiting fuses in nuclear power plants, characterized in that: include: Conducting a protection coordination test to obtain coordination test results of a plurality of test items after combining the fuse under test with a preset test device; each test item includes determining whether the coordination test result is qualified by determining whether the fuse under test operates or does not operate in accordance with the corresponding result; Then, a seismic test is performed to obtain seismic test results of the fuse to be tested performing an electrical safety function under set test conditions during an operating reference earthquake and a safety shutdown earthquake; The seismic test includes: The fuse to be tested is combined with a contactor and fixed to a seismic simulation device, and artificial seismic waves are generated by the seismic simulation device based on a set vibration response spectrum, so that the fuse to be tested performs at least one operating baseline seismic test and a safety shutdown seismic test to obtain a vibration response spectrum; During the operation benchmark earthquake test and the safety shutdown earthquake test, a constant current load test is also performed to obtain a current waveform flowing through the fuse under test during the earthquake test; Then, the legitimacy of each seismic test is determined based on the set vibration response spectrum, vibration response spectrum, and flowing current waveform. Determining the legitimacy of each seismic test based on the set vibration response spectrum, vibration response spectrum, and flowing current waveform includes: determining whether the vibration response spectrum envelops the set vibration response spectrum, and determining whether the flowing current of the fuse under test during the seismic test is continuous based on the flowing current waveform. If the vibration response spectrum envelops the set vibration response spectrum and the flowing current is continuous, the corresponding seismic test is determined to be legal; otherwise, the seismic test is determined to be unqualified. If all the earthquake tests are legal, then a post-earthquake test is performed on the fuse to be tested to obtain and determine whether the earthquake resistance test is qualified based on the verification data; The preset test device comprises a protection device (1), a contactor unit (2) and a test socket (3) for connecting to the fuse to be tested; a first end of the test socket (3) is connected to the expected current, and a second end of the test socket (3) is connected to the contactor unit (2); the protection device (1) is connected to the contactor unit (2) and controls the contactor unit (2) to be turned off or on according to a current signal flowing through the fuse to be tested; Each of the test items includes: Setting the low protection threshold, low protection threshold response time, high protection threshold and high protection threshold response time of the protection device (1), as well as the magnitude of the expected current, according to the test project requirements; Perform the following test N times: setting the initial state of the contactor unit (2) according to the test mode, then inputting the expected current into the fuse to be tested, until the contactor or protection device (1) is actuated, and recording the state of the fuse to be tested as the result of this test; wherein the test mode is a closing test or an opening test, the closing test means that the contactor unit (2) is in an open state before the test item is started, and the opening test means that the contactor unit (2) is in a closed state before the test item is started; If any test result fails, the corresponding test item is deemed unqualified; The protection coordination test also includes: Determine the corresponding low protection threshold, low protection threshold response time, high protection threshold, high protection threshold response time, expected current, test method, and the corresponding result of whether the fuse is operated when performing each test item according to the following table; The table is represented as: CO represents the test mode is the closing test, O represents the test mode is the opening test, IR represents the current value of the fuse under test when it starts with the maximum load, I F1 represents the current value corresponding to the pre-arcing time of the fuse to be tested for 10S, I represents the maximum arc current of the fuse to be tested, and I F2 Indicates the current value corresponding to the pre-arcing time 1S of the fuse to be tested, I F3 Indicates the current value corresponding to the pre-arcing time of the fuse to be tested of 0.1S, I MC Indicates the maximum breaking current of the fuse to be tested, I N represents the rated current of the combination of the contactor unit (2) and the fuse to be tested, T MIN It represents the minimum protection threshold response time pre-designed by the protection device (1), I MP represents the maximum protection threshold value pre-designed by the protection device (1), T1 represents the low protection threshold response time, K1 represents the low protection threshold, T2 represents the high protection threshold response time, and K2 represents the high protection threshold.

2. The safety level identification test method for high-voltage current-limiting fuses in nuclear power plants according to claim 1, characterized in that: The preset test device further includes a generator (4), a switch control unit (5), a frequency modulation unit (6) for adjusting the frequency of the expected current, a reactance adjustment unit (7) for adjusting the reactance of the test circuit, a capacitance adjustment unit (8) for adjusting the capacitance of the test circuit, a current measurement unit (9) for measuring the expected current, and a voltage measurement unit (10) for measuring the test voltage of the expected current. The output end of the generator (4) is connected to the first end of the test socket (3) via the switch control unit (5) and the reactance adjustment unit (7), the voltage measurement unit (10) and the current measurement unit (9) are connected to the first end of the test socket (3), and the first end of the test socket (3) is also connected to the ground via the frequency modulation unit (6) and the capacitance adjustment unit (8).

3. The safety level identification test method for high-voltage current-limiting fuses in nuclear power plants according to claim 2, characterized in that: The post-earthquake inspection tests include appearance and dimension inspection, temperature rise test, insulation test, tolerance test and waterproof test.

4. The safety level identification test method for high-voltage current-limiting fuses in nuclear power plants according to claim 1, characterized in that: The seismic test also includes: After the fuse to be tested is assembled with the contactor and fixed on the earthquake simulation device, a vibration response check is also performed to detect whether the fuse to be tested has a dangerous frequency; If a dangerous frequency exists, the seismic test is stopped.

5. The safety level evaluation test method for high-voltage current-limiting fuses in nuclear power plants according to claim 4, characterized in that: The vibration response check includes: The fuse to be tested is excited from three axis directions of a three-dimensional coordinate system using a preset white noise and lasts for a set time to detect whether the resonant frequency of the fuse to be tested is within a set range. If so, it is determined that the fuse to be tested has a dangerous frequency.

6. The safety level evaluation test method for high-voltage current-limiting fuses in nuclear power plants according to claim 3, characterized in that: The seismic test also includes: Before performing the operation benchmark earthquake test and the safety shutdown earthquake test, performing DC resistance measurement and X-ray inspection on the fuse to be tested to obtain reference data; After completing the operation benchmark earthquake test and the safety shutdown earthquake test, the DC resistance measurement and X-ray detection of the fuse to be tested are performed again to obtain post-test data, and then the qualification of the earthquake resistance test is judged based on the reference data and the post-test data.

7. The safety level evaluation test method for high-voltage current-limiting fuses in nuclear power plants according to claim 1, characterized in that: Before carrying out the seismic test, the following steps are also included: Conduct fuse type tests to obtain the specification parameter evaluation results of the fuse to be tested; Conduct temperature rise test on combination electrical appliances to obtain temperature rise test results of combination electrical appliances; A durability test is performed to obtain a durability test result of the fuse to be tested that changes with time due to degradation during normal operation.

8. The safety level evaluation test method for high-voltage current-limiting fuses in nuclear power plants according to claim 7, characterized in that: The fuse type test includes: appearance and size inspection, DC resistance measurement, breaking test, pre-arcing time current characteristic test, temperature rise test, striker test, insulation test, withstand test and waterproof test.

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