Device and method for evaluating opening aging and impulse breakdown characteristics of circuit breaker

Abstract

The present invention discloses a device and a method for evaluating the opening and aging and anti-shock breakdown characteristics of a circuit breaker. The device includes: a DC high-voltage power supply, a charging resistor Rs2, an energy storage capacitor Cs2, an adjusting resistor R1, a recovery voltage capacitor Ck, a charging resistor R2, a control switch GK2, a first resistor divider FY2, a second resistor divider FY3, a third resistor divider FY4, a metal oxide varistor MOA, and a test circuit breaker SP. The present invention can provide an effective means and evaluation criteria for the factory aging, material sampling inspection, and on-site aging of vacuum circuit breakers; it can solve the problem that the problem of re-breakdown commonly exists during the opening and closing of capacitor banks by vacuum circuit breakers and has long affected the safety of power grid reactive power compensation. The technical performance of the present invention is advanced, the production requirements are low, and a large number of high-voltage switch and test and detection device manufacturing enterprises can produce it, having great social benefits and significant economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment testing, and more specifically, to a device and method for evaluating the opening aging and anti-shock breakdown characteristics of a circuit breaker. Background Art

[0002] Vacuum circuit breakers are simple and economical, have strong switching capabilities, and are suitable for frequent operation. For reactive power compensation and voltage regulation in power grids of 500 kV and below, 12 / 40.5 kV vacuum circuit breakers are mostly selected. As of 2019, the installed capacity of 12 kV vacuum circuit breakers in the State Grid Corporation reached 85,997 sets (including 24,611 sets of Class C1 and 61,386 sets of Class C2), and the installed capacity of 40.5 kV vacuum circuit breakers reached 6,933 sets (including 2,782 sets of Class C1 and 4,151 sets of Class C2). When a vacuum circuit breaker closes a capacitor bank, the contacts are prone to welding, and when it opens a capacitor bank, the contact break is prone to re-breakdown, which may cause malignant accidents such as capacitor bank breakdown and explosion, threatening equipment safety and power grid operation. According to the statistics of the Shaoxing Power Company Test Station, which specializes in aging in the State Grid Corporation, the re-breakdown rate of 12 kV vacuum circuit breakers is about 0.99%, and the re-breakdown rate of 40.5 kV vacuum circuit breakers is as high as 4.79%. The re-breakdown rate is even higher during actual operation because effective aging and anti-re-breakdown level detection are not carried out before the circuit breaker is put into operation.

[0003] Conditioning is to eliminate burrs, metal and non-metal particles, and various contaminants inside the arc extinguishing chamber through certain technological processes, improve the surface condition of the contacts, and greatly increase the withstand voltage strength of the vacuum gap. It can also change the lattice structure of the contact surface, reduce the cold welding force, increase the toughness of the material, make the contact material less likely to fall off, and greatly reduce the restrike rate of the vacuum arc extinguishing chamber. The conditioning of the vacuum arc extinguishing chamber includes current conditioning and voltage conditioning. Current conditioning generates a vacuum arc between the contacts through a large current. The high temperature of the arc is used to remove a thin layer of material on the electrode surface, and at the same time, gases, oxides, and impurities in the electrode surface layer are eliminated, improving the surface condition of the contacts. The voltage conditioning test applies a high voltage (DC, power frequency, or impulse) to the vacuum arc extinguishing chamber to cause spark discharges between the contacts and between the contacts and the shielding cover. Through the action of the spark discharge, burrs and impurities on the contact surface are burned off, and the withstand voltage level of the vacuum arc extinguishing chamber is improved, forming a complement to current conditioning and being conducive to the rapid recovery of post-arc insulation. Before leaving the factory, the manufacturer generally conducts factory conditioning on each arc extinguishing chamber, usually using the power frequency high voltage conditioning process. A power frequency high voltage is applied across the break to cause multiple spark discharges at the break for 2 - 3 min. However, in the actual application of vacuum circuit breakers, the vacuum arc extinguishing chamber completes opening and closing driven by the operating mechanism, and the mechanical characteristics of the operating mechanism closely affect the anti-restrike performance of the vacuum circuit breaker. Only the factory conditioning of a single arc extinguishing chamber cannot guarantee the performance of the entire vacuum circuit breaker. A large number of practices have shown that conditioning tests on vacuum circuit breakers simulating actual opening and closing conditions can effectively reduce the restrike rate in the early stage of operation and detect defective products. When the restrike rate increases during the operation of the vacuum circuit breaker, it is also possible to try to repair the damaged contacts through conditioning tests and restore the insulation strength of the vacuum arc extinguishing chamber to reduce the restrike rate. Article 12.1.1.2 of the "Eighteen Major Anti-accident Measures for the Power Grid of the State Grid Corporation of China" (Revised Edition in 2018) stipulates that circuit breakers used for switching shunt capacitors and AC filters must be Type C2 circuit breakers. Before leaving the factory, the vacuum circuit breaker should be conditioned as a whole and a conditioning test report should be provided.

[0004] The "NB / T 42065-2016 Guide for Conditioning Tests of Vacuum Circuit Breakers for Capacitive Current Switching" provides two types of laboratory conditioning and anti-shock performance evaluation test circuits, namely the direct conditioning circuit and the synthetic conditioning circuit. Both use the capacitor bank switching test circuit. The three-phase direct conditioning test is as Figure 1As shown in the figure, C is a capacitor bank; TA is a current transformer; FD is a discharge coil; SP is the test sample; Um is the bus voltage to ground; Uf is the recovery voltage between the poles of the test sample; Uc is the voltage of the capacitor side to ground; Uo is the voltage of the neutral point of the capacitor bank to ground; I is the loop current. The three-circuit breaker test sample SP is connected between the bus and the capacitor bank C. By controlling the direct opening and closing of the vacuum circuit breaker, an arc is drawn at the contact opening in the initial stage of the circuit breaker opening. After the arc is extinguished, the system applies a transient overvoltage to the contact, simulating the actual opening condition of the circuit breaker. If a re-breakdown occurs, it is a high-voltage aging process. If there is no re-breakdown for 30 consecutive times, it is considered that the circuit breaker has sufficient anti-re-breakdown level. When there is no three-phase bus and the three-phase test condition is not available, single-phase direct aging can also be used as Figure 2 shown in the figure. C is a capacitor bank; TA is a current transformer; FD is a discharge coil; Um is the bus voltage to ground; Uf is the recovery voltage between the poles of the test sample; Uc is the voltage of the capacitor side to ground; I is the loop current; SP is the test sample. The test principle is the same as that of the three-phase direct aging test. The typical wiring of the combined aging circuit is as Figure 3 shown in the figure. DL is the circuit breaker of the test loop; T1 is the current loop transformer; T2 is the voltage loop transformer; T3 is the voltage loop regulator; C1 and C2 are the capacitor banks of the current loop; C3 and C4 are the capacitor banks of the voltage loop; L is the frequency modulation reactor; K1 is the knife switch of the voltage loop; SP1 is the phase to be tested of the test sample; SP2 and SP3 are the non-tested phases of the test sample; TA is the current transformer; FYn is the bus voltage measuring voltage divider; FYf is the recovery voltage measuring voltage divider; MOA is the lightning arrester; TV is the voltage transformer. On the left side of the test sample circuit breaker SP1 is the current source loop, and on the right side is the voltage source loop. When closing, first close the non-tested phases SP2 and SP3 of the test sample, and then close the tested phase SP1 of the test sample. When opening, first open SP2 and SP3, then open SP1, and then close K1 before the current of SP1 passes through zero. When the arc is extinguished, the power frequency voltage is boosted and superimposed on the residual voltage on C3, and together they are applied across the contact to form a very high recovery voltage. If a re-breakdown occurs, it is a high-voltage aging process. If there is no re-breakdown for 60 consecutive times, it is considered that the circuit breaker has sufficient anti-re-breakdown level. The above two aging test circuits are complex and costly, making it difficult to build and use them in large quantities. Moreover, using 30 - 60 consecutive opening without re-breakdown as the criterion for passing the aging test cannot quantitatively evaluate the anti-re-breakdown performance of the circuit breaker.

[0005] The above two test circuits are complex and costly, and many circuit breaker manufacturers do not have the conditions to set them up. Therefore, there are a large number of false reports and non-standard situations in factory burn-in. At the same time, because there is no burn-in method and device available for on-site burn-in, it leads to the fact that not all circuit breakers have carried out burn-in tests well before actual operation, and re-breakdown often occurs after operation. In summary, for the on-site burn-in of capacitor bank vacuum circuit breakers, it is hoped that there can be a portable burn-in test method that can simulate the actual closing conditions of the capacitor bank and quantitatively evaluate the anti-re-breakdown performance of the capacitor bank vacuum circuit breaker to guide the development of portable burn-in devices, with a small power supply capacity, simplicity, low cost, and high integration, which can not only meet the needs of factory burn-in, but also meet the on-site burn-in requirements such as circuit breaker spot checks, on-site burn-in, and anti-re-breakdown performance detection by power grid companies. Summary of the Invention

[0006] The present invention provides a device and method for circuit breaker opening burn-in and anti-impulse breakdown characteristic evaluation to solve the problems of how to conduct opening burn-in tests on circuit breakers and evaluate anti-impulse breakdown performance.

[0007] To solve the above problems, according to one aspect of the present invention, a device for circuit breaker opening burn-in and anti-impulse breakdown characteristic evaluation is provided. The device includes: a DC high-voltage power supply, a charging resistor Rs2, an energy storage capacitor Cs2, an adjusting resistor R1, a recovery voltage capacitor Ck, a charging resistor R2, a control switch GK2, a first resistor divider FY2, a second resistor divider FY3, a third resistor divider FY4, a metal oxide varistor MOA, and a test circuit breaker SP; wherein,

[0008] The positive pole of the DC high-voltage power supply is connected to one end of the charging resistor Rs2, and the other end of the charging resistor Rs2 is respectively connected to one end of the energy storage capacitor Cs2, one end of the adjusting resistor R1, and one end of the first resistor divider FY2. The other end of the adjusting resistor R1 is respectively connected to the other end of the recovery voltage capacitor Ck, one end of the charging resistor R2, and one end of the second resistor divider FY3. The other end of the charging resistor R2 is connected to one end of the control switch GK2, and the other end of the control switch GK2 is respectively connected to one end of the three-resistor divider FY4, one end of the metal oxide varistor MOA, and one end of the test circuit breaker SP; the other ends of the energy storage capacitor Cs2, the first resistor divider FY2, the recovery voltage capacitor Ck, the third resistor divider FY4, the metal oxide varistor MOA, and the test circuit breaker SP are all connected to the other end of the DC high-voltage power supply and grounded;

[0009] The first resistor divider FY2 is used to measure the voltage across the energy storage capacitor Cs2;

[0010] The second resistor divider FY3 is used to measure the voltage across the recovery voltage capacitor Ck and obtain the recovery voltage;

[0011] The third resistor divider FY4 is used to measure the voltage across the test circuit breaker SP and obtain the waveform of the contact voltage;

[0012] The metal oxide varistor MOA is used to limit the overvoltage generated by test abnormalities;

[0013] The DC high-voltage power supply is used to charge the energy storage capacitor Cs2;

[0014] By adjusting the resistor R1, the amplitude or rising rate of the dynamic recovery voltage is adjusted to change the number of re-breakdowns of the test circuit breaker, thereby realizing the adjustment of the breaking-in strength; by adjusting the dynamic recovery voltage gear, the recovery voltage at which no high-potential area re-breakdown occurs at the contact of the test circuit breaker is obtained, and the contact medium recovery curve is obtained. By comparing the contact medium recovery curve with the standard capacitive breaking recovery voltage, a quantitative evaluation of the anti-re-breakdown characteristics of the circuit breaker is carried out in different grades.

[0015] Preferably, when the DC high-voltage power supply charges the energy storage capacitor Cs2, the control switch GK2 is in the open state and the test circuit breaker SP is in the closed state;

[0016] When the energy storage capacitor Cs2 discharges, the control switch GK2 is in the closed state and the test circuit breaker SP is in the no-load switch state.

[0017] Preferably, the capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is greater than the sum of the contact capacitance of the test circuit breaker SP and the capacitance of the metal oxide varistor MOA.

[0018] Preferably, the capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to 3000 times the capacitance of the recovery voltage capacitor Ck; where C1 is the contact capacitance of the test circuit breaker SP and C2 is the capacitance of the metal oxide varistor MOA.

[0019] Preferably, the resistance value of the charging resistor R2 is 10 kΩ.

[0020] According to another aspect of the present invention, there is provided a method for evaluating the breaking-in and anti-re-breakdown characteristics of a circuit breaker based on the device for evaluating the breaking-in and anti-re-breakdown characteristics of a circuit breaker as described above, the method comprising:

[0021] Set the control switch GK2 to the open state and set the test circuit breaker SP to the closed state;

[0022] The DC high-voltage power supply charges the energy storage capacitor Cs2 through the charging resistor Rs2;

[0023] Set the control switch GK2 to the closed state and set the test circuit breaker SP to the no-load opening state;

[0024] The energy storage capacitor Cs2 charges the recovery voltage capacitor Ck through the recovery voltage regulating resistor R1 to form an exponentially rising recovery voltage; the amplitude or rising rate of the dynamic recovery voltage is adjusted by adjusting the resistor R1 to change the number of re-breakdowns of the test circuit breaker, thereby realizing the adjustment of the opening aging strength;

[0025] When the recovery voltage exceeds the breakdown voltage of the contact, the contact of the test circuit breaker SP is broken down to generate an arc. After the arc is extinguished, the recovery voltage capacitor Ck quickly charges the contact capacitor through the contact charging resistor R2 to synchronize with the recovery voltage. When the contact insulation recovery is insufficient, multiple re-breakdowns occur, and the contact insulation is subjected to opening aging by using multiple re-breakdown discharges;

[0026] By adjusting the dynamic recovery voltage level, a recovery voltage at which no high-potential region re-breakdown occurs at the contact of the test circuit breaker is obtained, and the contact dielectric recovery curve is obtained. By comparing the contact dielectric recovery curve with the standard capacitive opening recovery voltage, a graded quantitative evaluation of the anti-re-breakdown characteristic of the circuit breaker is performed.

[0027] Preferably, the capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is greater than the sum of the capacitance of the contact of the test circuit breaker SP and the capacitance of the metal oxide varistor MOA.

[0028] Preferably, the capacitance of the capacitor is determined by the following method, including: the capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to the product of 3000 and the capacitance of the recovery voltage capacitor Ck; where C1 is the capacitance of the contact of the test circuit breaker SP and C2 is the capacitance of the metal oxide varistor MOA.

[0029] Preferably, the resistance value of the charging resistor R2 is 10 kΩ.

[0030] Preferably, the method further includes:

[0031] Set the peak value of the dynamic recovery voltage to be not less than 3 times the phase voltage, and set the rising rate to 5 or 6 levels. The rising rate gradually increases from the low level to the high level. The rising time of the lowest level or the second lowest level is not less than 8.7 ms. The adjusting resistor R1 selects the corresponding resistance value according to the capacitance of the recovery voltage capacitor Ck designed for the rising time level.

[0032] The present invention provides a device and method for evaluating the opening aging and anti-breakdown characteristics of a circuit breaker, which can provide an effective means and evaluation criteria for the factory aging, material sampling inspection and on-site aging of vacuum circuit breakers; it can also be used as a test research means for studying the performance of vacuum circuit breaker products, improving the quality level of vacuum circuit breakers, and comprehensively improving the quality and reliability of vacuum circuit breakers from the entire life cycle of research and development, production and use, so as to solve the problem that the problem of re-breakdown during the opening and closing of vacuum circuit breakers for capacitor banks is widespread and has long affected the safety of reactive power compensation in the power grid. The present invention can provide guarantee for the safe opening and closing of reactive power compensation capacitor banks in power grids below 500 kV, further guarantee the safety of power grid equipment and personnel. Power grid companies, vacuum circuit breaker manufacturers, and even test research units have strong demands for the portable aging test and detection device; at the same time, the technical performance of the present invention is advanced and the production requirements are low, and a large number of high-voltage switch and test detection device manufacturers can produce it, which has great social benefits and significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The exemplary embodiments of the present invention can be more fully understood by referring to the following drawings:

[0034] Figure 1 is a schematic diagram of a typical three-phase direct aging test circuit;

[0035] Figure 2 is a schematic diagram of a typical single-phase direct aging test circuit;

[0036] Figure 3 is a schematic diagram of a typical synthetic aging test circuit;

[0037] Figure 4 is a schematic structural diagram of a device 400 for evaluating the opening aging and anti-breakdown characteristics of a circuit breaker according to an embodiment of the present invention;

[0038] Figure 5 (a) and (b) thereof are schematic diagrams of the opening aging test simulation waveforms under recovery voltages with different rising rates according to an embodiment of the present invention;

[0039] Figure 6 (a), (b), (c), (d) and (e) thereof are schematic diagrams of adjusting the opening aging intensity by adjusting the recovery voltage gear according to an embodiment of the present invention;

[0040] Figure 7 (a), (b), (c), (d), (e) and (f) thereof are schematic diagrams of the measured waveforms of the opening aging test according to an embodiment of the present invention;

[0041] Figure 8It is a flowchart of a method 800 for evaluating the opening aging and anti-shock breakdown characteristics of a circuit breaker according to an embodiment of the present invention. Detailed implementation manners

[0042] Now, exemplary embodiments of the present invention will be introduced with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0043] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. In addition, it can be understood that the terms defined in the commonly used dictionary should be understood to have a meaning consistent with the context of their related fields, and should not be understood as idealized or overly formal meanings.

[0044] Figure 4 It is a schematic structural diagram of a device 400 for evaluating the opening aging and anti-shock breakdown characteristics of a circuit breaker according to an embodiment of the present invention. As Figure 4 shown, the device for evaluating the opening aging and anti-shock breakdown characteristics of a circuit breaker provided by the embodiment of the present invention can provide an effective means and evaluation criteria for the factory aging, material sampling inspection and on-site aging of vacuum circuit breakers; it can also be used as a test research means for studying the product performance of vacuum circuit breakers, improving the quality level of vacuum circuit breakers, and comprehensively improving the quality and reliability of vacuum circuit breakers from the entire life cycle of research and development, production and use, so as to solve the problem that the problem of re-breakdown during the opening and closing of vacuum circuit breakers for capacitor banks is widespread and has long affected the safety of grid reactive power compensation. The present invention can provide guarantee for the safe opening and closing of reactive power compensation capacitor banks in power grids of 500 kV and below, further guarantee the safety of grid equipment and personnel. Grid companies, vacuum circuit breaker manufacturers, and even test research units have strong demands for the portable aging test and detection device; at the same time, the technical performance of the present invention is advanced and the production requirements are low. A large number of high-voltage switch and test detection device manufacturers can produce it, which has great social benefits and significant economic benefits. The device 400 for evaluating the opening aging and anti-shock breakdown characteristics of a circuit breaker provided by the embodiment of the present invention includes: a DC high-voltage power supply, a charging resistor Rs2, an energy storage capacitor Cs2, a regulating resistor R1, a recovery voltage capacitor Ck, a charging resistor R2, a control switch GK2, a first resistor divider FY2, a second resistor divider FY3, a third resistor divider FY4, a metal oxide varistor MOA, and a test circuit breaker SP.

[0045] Preferably, the positive electrode of the DC high-voltage power supply is connected to one end of the charging resistor Rs2, and the other end of the charging resistor Rs2 is respectively connected to one end of the energy storage capacitor Cs2, one end of the regulating resistor R1, and one end of the first resistor divider FY2. The other end of the regulating resistor R1 is respectively connected to the other end of the recovery voltage capacitor Ck, one end of the charging resistor R2, and one end of the second resistor divider FY3. The other end of the charging resistor R2 is connected to one end of the control switch GK2. The other end of the control switch GK2 is respectively connected to one end of the three-resistor divider FY4, one end of the metal oxide arrester MOA, and one end of the test circuit breaker SP. The other ends of the energy storage capacitor Cs2, the first resistor divider FY2, the recovery voltage capacitor Ck, the third resistor divider FY4, the metal oxide arrester MOA, and the test circuit breaker SP are all connected to the other end of the DC high-voltage power supply and grounded.

[0046] Preferably, the first resistor divider FY2 is used to measure the voltage across the energy storage capacitor Cs2.

[0047] Preferably, the second resistor divider FY3 is used to measure the voltage across the recovery voltage capacitor Ck and obtain the recovery voltage.

[0048] Preferably, the third resistor divider FY4 is used to measure the voltage across the test circuit breaker SP and obtain the port voltage waveform.

[0049] Preferably, the metal oxide arrester MOA is used to limit the overvoltage generated by test abnormalities.

[0050] Preferably, the DC high-voltage power supply is used to charge the energy storage capacitor Cs2.

[0051] Preferably, the amplitude or rising rate of the dynamic recovery voltage is adjusted by the regulating resistor R1 to change the number of re-breakdowns of the test circuit breaker, thereby realizing the adjustment of the breaking and aging strength. By adjusting the dynamic recovery voltage level, the recovery voltage at which no high-potential-region re-breakdown occurs at the port of the test circuit breaker is obtained, and the port dielectric recovery curve is obtained. By comparing the port dielectric recovery curve with the standard capacitive breaking recovery voltage, a quantitative evaluation of the anti-re-breakdown characteristics of the circuit breaker is carried out in different grades.

[0052] The key to successful interruption of a circuit breaker lies in the competition between the dielectric recovery speed of the arc gap after the arc current passes through zero and the rising speed of the system transient recovery voltage. During the interruption process, when the dielectric recovery speed of the arc gap continuously exceeds the rising speed of the recovery voltage, the interruption is successful; otherwise, re-breakdown will occur. The most direct way to obtain the anti-rebreakdown performance of a vacuum circuit breaker is to measure the post-arc dielectric recovery characteristic curve of this vacuum circuit breaker. When measuring the dielectric recovery curve, the primary consideration is how to apply the recovery voltage during the interruption process of the circuit breaker. Therefore, the present invention proposes a method of applying a dynamic recovery voltage to generate multiple re-breakdowns for aging, while measuring the dielectric recovery characteristics of the breaker contact. By comparing it with the recovery voltage specified in the standard for breaking capacitor banks, the anti-rebreakdown characteristics of the breaker contact can be quantitatively evaluated.

[0053] Adopt a circuit as Figure 4 shown to generate a dynamic recovery voltage during the no-load interruption process of the circuit breaker, conduct interruption aging and measure the dielectric recovery characteristic curve. The reason for choosing the no-load interruption without an arc process is to simulate the more severe recovery voltage application method in the actual working conditions of breaking capacitor banks. When breaking capacitor banks, re-breakdown often occurs under the condition of short arcing, where the breaking current is small (about 400 A), the arc duration is short (less than 1 ms), and the energy of the arc is very low, which is very close to the no-load interruption. The method of applying a dynamic recovery voltage simulates the most severe working conditions of actual interruption and excludes the interference of arc dispersion, facilitating the horizontal comparison of the interruption performance of circuit breakers.

[0054] Preferably, when the DC high-voltage power supply charges the energy storage capacitor Cs2, the control switch GK2 is in the open state, and the test circuit breaker SP is in the closed state;

[0055] When the energy storage capacitor Cs2 discharges, the control switch GK2 is in the closed state, and the test circuit breaker SP is in the no-load switch state.

[0056] Preferably, the capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is greater than the sum of the contact capacitance of the test circuit breaker SP and the capacitance of the metal oxide arrester MOA.

[0057] Preferably, the capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to 3000 times the capacitance of the recovery voltage capacitor Ck; where C1 is the contact capacitance of the test circuit breaker SP, and C2 is the capacitance of the metal oxide arrester MOA.

[0058] Preferably, the resistance value of the charging resistor R2 is 10 kΩ.

[0059] In the embodiments of the present invention, the energy storage capacitor Cs2 and the recovery voltage capacitor Ck are arranged such that Cs is much larger than Ck, and Ck is much larger than the sum of the breaker contact capacitance and the arrester capacitance, so as to minimize the influence of the above capacitors and their voltage changes on the recovery voltage during the breaking conditioning process. The maximum contact capacitance is C1, and the equivalent capacitance of the arrester is C2. Take Ck approximately 5*(C1 + C2), and Cs2 is not less than 3000*Ck.

[0060] For the dynamic recovery voltage curve: Referring to the TRV regulations for capacitor bank current breaking type tests in GB1984 (peak value is 3 times the phase voltage, rise time is 8.7 ms), design the dynamic recovery voltage peak value not less than 3 times the phase voltage, set the rising rate in 5 or 6 gears, and the rising rate gradually increases from the low gear to the high gear. The rising time of the lowest gear or the second lowest gear is not less than 8.7 ms. The recovery voltage regulating resistor R1 is selected according to the designed rising time gear and the value of Ck.

[0061] For the contact charging resistor R2: During the contact dielectric recovery process, R2 is used to charge the contact non-oscillatorily by the recovery voltage capacitor Ck to quickly apply the recovery voltage. During the contact re-breakdown process, R2 can limit the discharge current of Ck to the contact, which can not only reduce the injection of re-breakdown arc energy to facilitate the quick arc extinction of the contact, but also reduce the amplitude of the instantaneous drop of the recovery voltage during the re-breakdown process. Select R2 approximately 10 kΩ, which can be quickly charged to synchronize with the recovery voltage after the contact arc extinction. During the contact re-breakdown process, the discharge current of Ck through R2 is very small, about several A, and will decay to less than about 500 mA in dozens of μs; the re-breakdown arc energy of the contact mainly comes from the short-circuit discharge of the contact capacitance. The contact capacitance of the vacuum circuit breaker is about 250 pF, and the maximum energy storage is only about 0.1 J. According to the current-carrying and breaking capabilities of the vacuum circuit breaker contacts, during the re-breakdown process, the arc will not damage the contacts, the contact can extinguish the arc within several μs, the recovery voltage will be instantaneously pulled down, the higher the re-breakdown voltage, the longer the arc extinction time, and the greater the amplitude of the instantaneous drop of the recovery voltage.

[0062] For the resistance value verification of the recovery voltage regulating resistor R1 and the contact charging resistor R2: During the breaking conditioning process, before the breaking conditioning control switch GK2 is closed and the test breaker SP is opened, the energy storage capacitor Cs2 will discharge through R1 and R2. If R1 and R2 are too small and Cs2 discharges too much, it will cause the reduction of the subsequent test recovery voltage. When R1 takes the minimum value, the voltage of Cs2 decays to no more than 10%, which has little influence on the subsequent breaking conditioning test recovery voltage, indicating that the selected R1 and R2 are acceptable.

[0063] In the embodiments of the present invention, the test process includes:

[0064] (1) Before the test, GK2 is opened and the test breaker SP is closed;

[0065] (2) The DC high-voltage power supply charges the energy storage capacitor Cs2 through the charging resistor Rs2;

[0066] (3) After the control switch GK2 is closed, the test circuit breaker SP performs no-load opening. Cs2 charges the recovery voltage capacitor Ck through the recovery voltage regulating resistor R1 to form an exponentially rising recovery voltage;

[0067] (4) When the recovery voltage exceeds the breakdown voltage of the contact, the contact of SP is broken down to generate an arc. Since the equivalent capacitance of the contact is very small, the arc is quickly extinguished and the insulation is restored. After the arc is extinguished, Ck can quickly charge the contact capacitance through the contact charging resistor R2 to synchronize with the recovery voltage. When the insulation recovery of the contact is insufficient, multiple re-breakdowns will occur. By using the multiple re-breakdown discharges, the insulation of the contact can be subjected to opening and aging. The multiple re-breakdown voltage curve can also represent the dielectric recovery ability of the small current zero-arcing time opening of the SP capacitor bank, which is used to quantitatively evaluate the anti-re-breakdown performance.

[0068] During the test process, by changing the test voltage or the resistor R1, the amplitude or the rising rate of the dynamic recovery voltage can be adjusted. Correspondingly, the number of re-breakdowns of the test object can be changed, so as to realize the adjustment of the opening and aging intensity. During the test process, by adjusting the resistor R1, the rising rate of the recovery voltage can be changed. Thus, the resistor voltage dividers FY2, FY3 and FY4 are respectively used to measure the voltage of Cs2, the recovery voltage and the contact voltage waveforms, and the metal oxide varistor MOA is used to limit the overvoltage generated by test abnormalities.

[0069] Figure 5 To obtain the test waveforms by simulation at different rising rates of the recovery voltage. During the opening process of the test object, when the dielectric recovery strength of the contact is higher than the recovery voltage, no re-breakdown occurs at the contact, as shown in Figure 5 (a) of. During the opening process of the test object, when the contact voltage is quickly charged to the recovery voltage and reaches the dielectric recovery strength, a re-breakdown occurs at the contact. The contact capacitance is very small, and the energy of the discharge arc is not large and the arc is quickly extinguished. The contact is quickly charged to the recovery voltage again. When it reaches the dielectric recovery strength again, a re-breakdown will occur again. Such multiple re-breakdowns are repeated until the dielectric recovery strength exceeds the recovery voltage and then it will end, as shown in Figure 5 (b) of. Considering that the insulation strength is relatively low when the contact is just separated, the multiple breakdowns occurring at this time belong to re-ignition. Only when a re-breakdown occurs in the high potential region (the breakdown voltage is 1.5 times the phase voltage), it is considered to be within the scope of re-breakdown. Therefore, by adjusting the dynamic recovery voltage gear to make no re-breakdown occur in the high potential region at the contact, it can be considered that the recovery voltage curve is very close to the contact dielectric recovery curve at this time. By comparing it with the recovery voltage, the anti-re-breakdown characteristics of the contact can be quantitatively evaluated in different grades.

[0070] The breaking aging method proposed in the embodiments of the present invention is voltage aging. During the no-load breaking process of the circuit breaker, a voltage with an amplitude close to the transient recovery voltage (TRV) and a very fast rising rate is repeatedly applied across the contact gap, causing the contact gap to be broken down multiple times, generating high-voltage small arcs to clean the micro-defects in the vacuum interrupter. This is equivalent to performing multiple voltage aging processes in one breaking process, improving the aging efficiency. Since the single-arc energy in voltage aging is relatively low, the aging intensity can be adjusted by controlling the number of contact gap breakdowns. Both the peak value and the rising rate of the recovery voltage will affect the number of restrikes during the breaking process. To be equivalent to the actual working conditions, the peak value of the recovery voltage remains unchanged during the test, and the aging intensity is adjusted by adjusting the rising rate of the recovery voltage. Figure 6 (a), (b), (c), (d), and (e) of Figure 6 are respectively the simulation waveforms of the no-load breaking aging of the circuit breaker at different recovery voltage levels. The green line is the recovery voltage curve, the blue line is the assumed dielectric recovery curve, and the red line is the contact gap voltage curve. It can be seen that as the recovery voltage level increases, the number of restrikes of the contact gap gradually increases, and the aging intensity gradually increases.

[0071] The following specifically illustrates the embodiments of the present invention by examples.

[0072] According to the test method for the movable breaking aging and anti-restrike performance quantification evaluation of the vacuum circuit breaker simulating no-load breaking with different levels of dynamic recovery proposed in the present invention, a breaking aging test circuit for a 12 kV capacitor bank vacuum circuit breaker is designed as follows.

[0073] The test circuit adopts the circuit topology as Figure 4 shown. The design of the recovery voltage curve refers to the TRV regulation (peak value 28 kV, rising time 8.7 ms) for the capacitor bank current breaking type test in GB1984. The peak value is not less than 1.2 times of 28 kV, taking 35 kV; the rising time is not less than 8.7 ms, and is set to five levels of 7 ms, 3.5 ms, 1.8 ms, 1 ms, and 0.5 ms.

[0074] The estimated maximum fracture capacitance is about 150 pF, and the equivalent capacitance of the arrester is about 100 pF. Therefore, Ck = 1150 pF and Cs2 = 5 μF are taken, and accordingly, the recovery voltage regulating resistors R1 = 1.6 MΩ, 0.8 MΩ, 0.4 MΩ, 0.2 MΩ, 0.1 MΩ are selected, and the fracture charging resistor R2 = 10 kΩ. The maximum fracture charging time constant is 2.5 μs, and after the fracture is extinguished, it can be quickly charged to synchronize with the recovery voltage. During the process of fracture restriking, the discharge current of Ck through R2 is very small, with a maximum peak value of 3.5 A and a decay time constant of 11.5 μs. It will decay to less than about 500 mA at 23 μs. The energy of the fracture restriking arc mainly comes from the short-circuit discharge of the fracture capacitance. The fracture capacitance is about 250 pF, and the maximum energy storage is only about 0.1 J. According to the current-carrying and breaking capabilities of the contacts of the vacuum circuit breaker, during the restriking process, the arc will not damage the contacts.

[0075] The VS1-12 circuit breaker of Shandong Taikai Vacuum Company was used for breaking and aging, and the aging test waveforms under different recovery voltage rise rates were obtained, as Figure 7 shown in (a), (b), (c), (d), (e) and (f) below. The curve located above is the recovery voltage waveform, and the curve located below is the fracture voltage waveform. The summary is as follows:

[0076] 1) The variation law of the aging test waveform is consistent with the design. The aging test can perform high-voltage aging on the test sample by applying the recovery voltage to generate multiple restrikes, indicating that the test circuit design is effective.

[0077] 2) During the aging test process, the fracture voltage waveform, especially the multiple restrike voltage waveforms, can represent the lower limit of the dielectric recovery ability of the test sample for breaking and is used to observe the change of the anti-restrike performance of the test sample.

[0078] 3) Gradually increase the gear to carry out the aging test. Conduct several aging tests at a certain gear. The criterion for passing the aging of this gear can be that no restrike occurs in the high-potential area, and the highest gear passed is used as the basis for the classification and evaluation of the anti-restrike performance of the test sample.

[0079] 4) The measured recovery voltage is affected by the performance of the test sample and stray parameters, and there will be reasonable deviations and randomness from the design expectation.

[0080] 5) The recovery voltage curves of the first and second gears of the breaking and aging are slightly higher than the capacitive breaking standard TRV. The occurrence of restrikes in the high-voltage area in the aging test of this gear indicates that the restrike risk of the test sample is relatively large and aging should be carried out, which can be used as the starting gear for the breaking and aging. The recovery voltage parameters of the fourth and fifth gears of the breaking and aging are much higher than the capacitive breaking standard TRV. The passing of the aging test of this gear indicates that the test sample has sufficient margin for anti-restrike and can be safely and reliably switched, which can be used as the end gear for the breaking and aging.

[0081] In view of the current situation that the re - breakdown rate of vacuum circuit breakers for capacitor banks widely used in the power grid is relatively high, and there is a lack of simple aging and quantitative evaluation methods for anti - re - breakdown performance, the present invention proposes a device and method for the movable breaking aging and quantitative evaluation of anti - re - breakdown performance of vacuum circuit breakers. It simulates the actual operating conditions of opening and closing capacitor banks. During the closing process of the circuit breaker, high - voltage and large - capacity aging is carried out through closing inrush current. During the opening process, aging is carried out by applying a dynamic recovery voltage to generate multiple re - breakdowns during no - load opening. At the same time, the re - breakdown voltage of the contact is measured to represent the dielectric recovery characteristics, and it is compared with the capacitive breaking recovery voltage (TRV) specified by the circuit breaker standard to evaluate the anti - re - breakdown performance, so as to improve and detect the quality and reliability of vacuum circuit breakers in important links such as factory production, acceptance, and operation of vacuum circuit breakers.

[0082] Figure 8 FIG. 800 is a flowchart of a method for evaluating the breaking aging and anti - impulse breakdown characteristics of a circuit breaker according to an embodiment of the present invention. As Figure 8 shown, the method 800 for evaluating the breaking aging and anti - impulse breakdown characteristics of a circuit breaker provided by the embodiment of the present invention, based on the device for evaluating the breaking aging and anti - impulse breakdown characteristics of a circuit breaker as described above, starts from step 801. In step 801, the control switch GK2 is set to the open state, and the test circuit breaker SP is set to the closed state.

[0083] In step 801, the DC high - voltage power supply charges the energy - storage capacitor Cs2 through the charging resistor Rs2.

[0084] In step 802, the control switch GK2 is set to the closed state, and the test circuit breaker SP is set to the no - load open state.

[0085] In step 803, the energy - storage capacitor Cs2 charges the recovery - voltage capacitor Ck through the recovery - voltage regulating resistor R1 to form an exponentially rising recovery voltage; the amplitude or rising rate of the dynamic recovery voltage is adjusted by adjusting the resistor R1 to change the number of re - breakdowns of the test circuit breaker, thereby realizing the adjustment of the breaking aging intensity.

[0086] In step 804, when the recovery voltage exceeds the contact breakdown voltage, the contact of the test circuit breaker SP is broken down to generate an arc. After the arc is extinguished, the recovery - voltage capacitor Ck quickly charges the contact capacitor through the contact charging resistor R2 to synchronize with the recovery voltage. When the contact insulation recovery is insufficient, multiple re - breakdowns occur, and the contact insulation is aged by using multiple re - breakdown discharges.

[0087] In step 805, by adjusting the dynamic recovery - voltage gear, the recovery voltage at which no high - potential - area re - breakdown occurs at the contact of the test circuit breaker is obtained, the contact dielectric recovery curve is acquired, and by comparing the contact dielectric recovery curve with the standard capacitive breaking recovery voltage, a graded quantitative evaluation of the anti - re - breakdown characteristics of the circuit breaker is carried out.

[0088] Preferably, the capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is greater than the sum of the capacitance of the test circuit breaker SP and the capacitance of the metal oxide varistor MOA.

[0089] Preferably, the method determines the capacitance in the following manner, including: the capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to the product of 3000 and the capacitance of the recovery voltage capacitor Ck; where C1 is the capacitance of the test circuit breaker SP and C2 is the capacitance of the metal oxide varistor MOA.

[0090] Preferably, the resistance value of the charging resistor R2 is 10 kΩ.

[0091] Preferably, the method further includes:

[0092] Set the dynamic recovery voltage peak to be not less than 3 times the phase voltage, set the rising rate in 5 or 6 gears, the rising rate gradually increases from the low gear to the high gear, the rising time of the lowest gear or the second lowest gear is not less than 8.7 ms, and adjust the resistance R1 to select the corresponding resistance value according to the capacitance of the recovery voltage capacitor Ck of the designed rising time gear.

[0093] The method 800 for evaluating the opening aging and anti-impulse breakdown characteristics of a circuit breaker in an embodiment of the present invention corresponds to the device 400 for evaluating the opening aging and anti-impulse breakdown characteristics of a circuit breaker in another embodiment of the present invention, which will not be elaborated here.

[0094] The present invention has been described by referring to a few embodiments. However, as is well known to those skilled in the art, as defined by the appended patent claims, other embodiments equivalent to those disclosed above of the present invention equally fall within the scope of the present invention.

[0095] Generally, all terms used in the claims are interpreted according to their ordinary meanings in the technical field, unless otherwise clearly defined therein. All references to "a / the / this [device, component, etc.]" are open to interpretation as at least one instance of the device, component, etc., unless otherwise clearly stated. The steps of any method disclosed here do not necessarily have to be run in the exact order disclosed, unless clearly stated.

[0096] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0097] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of multiple flows and / or blocks.

[0098] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of multiple flows and / or blocks.

[0099] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks or the combination of multiple flows and / or blocks.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still can modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A device for evaluating the opening aging and anti-impulse breakdown characteristics of a circuit breaker, characterized in that, The device includes: a DC high-voltage power supply, a charging resistor Rs2, an energy storage capacitor Cs2, an adjusting resistor R1, a recovery voltage capacitor Ck, a charging resistor R2, a control switch GK2, a first resistor divider FY2, a second resistor divider FY3, a third resistor divider FY4, a metal oxide varistor MOA, and a test circuit breaker SP; wherein, The positive pole of the DC high-voltage power supply is connected to one end of the charging resistor Rs2, and the other end of the charging resistor Rs2 is respectively connected to one end of the energy storage capacitor Cs2, one end of the adjusting resistor R1, and one end of the first resistor divider FY2. The other end of the adjusting resistor R1 is respectively connected to the other end of the recovery voltage capacitor Ck, one end of the charging resistor R2, and one end of the second resistor divider FY3. The other end of the charging resistor R2 is connected to one end of the control switch GK2, and the other end of the control switch GK2 is respectively connected to one end of the three-resistor divider FY4, one end of the metal oxide varistor MOA, and one end of the test circuit breaker SP. The other ends of the energy storage capacitor Cs2, the first resistor divider FY2, the recovery voltage capacitor Ck, the third resistor divider FY4, the metal oxide varistor MOA, and the test circuit breaker SP are all connected to the other end of the DC high-voltage power supply and grounded; The first resistor divider FY2 is used to measure the voltage across the energy storage capacitor Cs2; The second resistor divider FY3 is used to measure the voltage across the recovery voltage capacitor Ck to obtain the recovery voltage; The third resistor divider FY4 is used to measure the voltage across the test circuit breaker SP to obtain the fault voltage waveform; The metal oxide varistor MOA is used to limit the overvoltage generated by abnormal tests; The DC high-voltage power supply is used to charge the energy storage capacitor Cs2; By adjusting the resistor R1, the amplitude or rising rate of the dynamic recovery voltage is adjusted to change the number of re-breakdowns of the test circuit breaker, thereby realizing the adjustment of the breaking aging strength; by adjusting the dynamic recovery voltage gear, a recovery voltage waveform in which no high-potential region re-breakdown occurs at the fault of the test circuit breaker is obtained, thereby obtaining the fault medium recovery curve, and by comparing the fault medium recovery curve with the standard capacitive breaking recovery voltage, a graded quantitative evaluation of the anti-re-breakdown characteristics of the circuit breaker is carried out.

2. The device according to claim 1, wherein When the DC high-voltage power supply charges the energy storage capacitor Cs2, the control switch GK2 is in the open state, and the test circuit breaker SP is in the closed state; When the energy storage capacitor Cs2 discharges, the control switch GK2 is in the closed state, and the test circuit breaker SP is in the no-load switch state.

3. The device according to claim 1, characterized in that, The capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is much greater than the sum of the fault capacitances of the test circuit breaker SP and the capacitance of the metal oxide varistor MOA.

4. The device according to claim 3, characterized in that, The capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to the product of 3000 and the capacitance of the recovery voltage capacitor Ck; where C1 is the contact capacitance of the test circuit breaker SP, and C2 is the capacitance of the metal oxide arrester MOA.

5. The device according to claim 1, characterized in that, The resistance value of the charging resistor R2 is 10 kΩ.

6. A method for evaluating the opening aging and anti-impulse breakdown characteristics of a circuit breaker based on the device for evaluating the opening aging and anti-impulse breakdown characteristics of a circuit breaker according to any one of claims 1-5, characterized in that, The method includes: Set the control switch GK2 to the open state and set the test circuit breaker SP to the closed state; The DC high voltage power supply charges the energy storage capacitor Cs2 through the charging resistor Rs2; Set the control switch GK2 to the closed state and set the test circuit breaker SP to the no-load opening state; The energy storage capacitor Cs2 charges the recovery voltage capacitor Ck through the recovery voltage regulating resistor R1 to form an exponentially rising recovery voltage; the dynamic recovery voltage amplitude or rising rate is adjusted by adjusting the resistor R1 to change the number of re-breakdowns of the test circuit breaker, thereby realizing the adjustment of the opening aging strength; When the recovery voltage exceeds the contact breakdown voltage, the contact of the test circuit breaker SP is broken down to generate an arc. After the arc is extinguished, the recovery voltage capacitor Ck quickly charges the contact capacitance through the contact charging resistor R2 to synchronize with the recovery voltage. When the contact insulation recovery is insufficient, multiple re-breakdowns occur, and the contact insulation is aged by multiple re-breakdown discharges; By adjusting the dynamic recovery voltage level, a recovery voltage waveform in which no high-potential region re-breakdown occurs at the contact of the test circuit breaker is obtained, thereby obtaining the contact dielectric recovery curve. By comparing the contact dielectric recovery curve with the standard capacitive opening recovery voltage, a graded quantitative evaluation of the breaker's anti-re-breakdown characteristics is carried out.

7. The method according to claim 6, characterized in that, The capacitance of the energy storage capacitor Cs2 is greater than the capacitance of the recovery voltage capacitor Ck, and the capacitance of the recovery voltage capacitor Ck is much greater than the sum of the contact capacitance of the test circuit breaker SP and the capacitance of the metal oxide arrester MOA.

8. The method according to claim 7, wherein The method determines the capacitance in the following way, including: the capacitance of the recovery voltage capacitor Ck is the product of a preset multiple threshold and (C1 + C2), and the capacitance of the energy storage capacitor Cs2 is greater than or equal to the product of 3000 and the capacitance of the recovery voltage capacitor Ck; where C1 is the contact capacitance of the test circuit breaker SP, and C2 is the capacitance of the metal oxide arrester MOA.

9. The method according to claim 6, wherein The resistance value of the charging resistor R2 is 10 kΩ.

10. The method according to claim 6, characterized in that The method further includes: Set the peak value of the dynamic recovery voltage to be not less than 3 times the phase voltage, and set the rising rate to 5 or 6 levels. The rising rate gradually increases from the low level to the high level. The rising time of the lowest level or the second lowest level is not less than 8.7 ms. The resistor R1 is selected according to the capacitance of the recovery voltage capacitor Ck corresponding to the designed rising time level.

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