Multi-state quantitative evaluation method for anti-restrike performance of vacuum circuit breaker

Abstract

The invention provides a multi-state quantitative evaluation method for anti-restrike performance of a vacuum circuit breaker. The multi-state quantitative evaluation method comprises the following steps: carrying out closing and aging primary loop design; carrying out primary loop design of on-off aging; integrally designing the overall test loop topology of the aging test detection device; carrying out parameter design and device type selection; carrying out secondary measurement; carrying out control and protection design, and carrying out signal processing and parameter calculation; and the overall structure of the device is designed. According to the multi-state quantitative evaluation method for the anti-restrike performance of the vacuum circuit breaker, the purpose of aging can be achieved in a closing aging test without causing contact damage, so that the adjustment of the breaking aging strength is realized, and the anti-restrike performance of the test object is evaluated through the fastest rising rate of the test object without high-potential region restrike, so that the contact is prevented from being burnt, and the service life of the test object is prolonged. The test voltage is properly improved to increase the pre-breakdown time so as to ensure the aging strength, and the design of dehumidification, dust prevention and the like is carried out in the case, so that the reliability in different working environments is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of circuit breakers, and in particular to a multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker. Background Art

[0002] A vacuum circuit breaker is a switching device that uses vacuum as an arc extinguishing medium. Its working principle is to remove the arc energy in the circuit breaker contacts. When the contacts are opened in a vacuum, an arc is generated, but the arc is easy to extinguish because the ions, metal vapor and electrons in the arc can directly condense above the contact surface area, thereby quickly restoring the strength of the dielectric. The heavy breakdown resistance of the vacuum circuit breaker can be quantitatively evaluated through multiple state quantities, mainly including vacuum degree, opening / closing coil current, contact temperature and remaining electrical life. By quantitatively evaluating the vacuum degree, opening / closing coil current, contact temperature and remaining electrical life of the vacuum circuit breaker, its heavy breakdown resistance can be effectively evaluated, and appropriate algorithms can be used for state evaluation to ensure the safe operation of the power grid.

[0003] The multi-state quantitative evaluation method for the heavy breakdown resistance performance of vacuum circuit breakers in the existing technology is inefficient and unreliable. It is unable to simulate the circuit breaker after a period of operation by configuring an arc extinguishing chamber with design defects, and lacks a standardized and systematic verification process. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a multi-state quantitative evaluation method for the heavy breakdown performance of a vacuum circuit breaker to solve the problems raised in the above-mentioned background technology. The present invention can realize the adjustment of the breaking aging strength, and evaluate the heavy breakdown performance of the test piece through the fastest rising rate when the test piece does not suffer from heavy breakdown in the high potential area to avoid burning the contacts, appropriately increase the test voltage and increase the pre-breakdown time to ensure the aging strength, and carry out dehumidification and dustproof designs in the chassis to ensure the reliability under different working environments, and has a standardized and systematic verification process.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solution: a multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker, comprising the following steps:

[0006] Step 1: Design a closed and aged primary circuit;

[0007] Step 2: Design a primary circuit for breaking and aging;

[0008] Step 3: Integrated design of the overall test loop topology of the aging test and detection device;

[0009] Step 4: Perform parameter design and device selection;

[0010] Step 5: Conduct secondary measurement;

[0011] Step 6: Control and protection design, signal processing and parameter calculation;

[0012] Step 7: Design the overall structure of the device.

[0013] Furthermore, in the step 1, the circuit breaker and the closing circuit control switch are both in the open state before the test. A large-capacity energy storage capacitor is used as a closing and aging power supply to provide the test voltage and closing surge current. After the closing circuit control switch is closed, the circuit breaker of the test product performs a closing operation. After the pre-breakdown of the break occurs, the discharge reactor oscillates and discharges, forming a high-frequency and high-current between the contacts to simulate the closing surge current, and the pre-breakdown arc energy is used to perform closing aging on the contacts.

[0014] Furthermore, in the closing aging test, the pre-breakdown time, the closing surge current amplitude and the ratio of the pre-breakdown arc energy in the aging test to the pre-breakdown arc energy under the closing surge current waveform specified in the type test are adjusted by changing the test voltage. By adjusting the ratio of the pre-breakdown arc energy, the device can achieve the best aging effect.

[0015] Furthermore, in step 2, the test circuit breaker is in a closed state before the test, and the control switch is in an open state. A large-capacity energy storage capacitor is used as an opening and closing aging power supply to output an opening and closing aging test voltage. After the opening and closing circuit control switch is closed, the test circuit breaker is opened without load, and the large-capacity energy storage capacitor charges the recovery voltage capacitor through the recovery voltage regulating resistor to form an exponentially rising dynamic recovery voltage applied to the test fracture. After each discharge and arc extinguishing of the fracture, the breaking circuit control switch can quickly charge the fracture capacitor through the fracture charging resistor, so that the fracture voltage is synchronized with the recovery voltage. When the fracture voltage of the test circuit breaker continuously exceeds the recovery characteristics of the insulating medium, multiple re-breakdowns will occur. The insulation of the fracture can be opened and aged by using multiple re-breakdown discharges. The multiple re-breakdown voltage curve can also represent the small current zero arcing time breaking medium recovery characteristic curve of the capacitor group of the test circuit breaker, which is used to quantitatively evaluate the anti-re-breakdown performance.

[0016] Furthermore, during the test, by changing the test voltage or resistance, adjusting the dynamic recovery voltage amplitude or rising rate, the number of restrike times of the test piece can be changed accordingly, the breaking aging strength can be adjusted, and the anti-restrike performance of the test piece can be evaluated by the fastest rising rate when no restrike in the high potential area occurs.

[0017] Furthermore, in step three, a DC high-voltage power supply is used to charge the energy storage capacitors of the closing and opening aging circuits at the same time, and a MΩ-level charging resistor is used to isolate the circuit and control the charging efficiency, and the closing and opening aging functions are switched by controlling the opening and closing of the switch.

[0018] Furthermore, in the step five, by issuing instructions to the charging control module, the output of the DC charging power supply is adjusted to control the closing and opening of the circuit test voltage; by issuing instructions to the aging test process control module, the closing and opening of the aging circuit control switch, the selection of the resistance value of the aging test recovery voltage adjustment resistor, and the closing and opening of the test circuit breaker are controlled to realize the control of the three test modes of "closing aging only", "opening aging only" and "closing + opening".

[0019] Furthermore, the control and protection design includes three conditioning modes: "closing conditioning only", "breaking conditioning only" and "closing + breaking conditioning". The protection design also includes safety design, and the safety design includes electrical interlocking design, power isolation and grounding, and container group discharge operation requirements.

[0020] Furthermore, signal processing is used to eliminate the influence of arcing on the test circuit breaker break current signal, test circuit breaker break voltage signal, and test circuit breaker coil current signal during the closing test and the breaking test. According to the basic characteristics of each signal, wavelet transform is first used for filtering, and the effective data segment is intercepted for closing aging strength calculation and anti-severe breakdown performance evaluation.

[0021] Furthermore, the parameter calculation obtains the estimated breakdown time under phase voltage, the estimated breakdown time under closing voltage, the frequency and amplitude of closing surge current according to the collected signals, and calculates the closing energy and closing energy coefficient; according to the breaking voltage waveform, the high voltage area breakdown voltage and time are obtained, the number of high voltage area breakdowns is counted, and the heavy breakdown gears before and after aging, as well as the aging times of each gear during the aging process are obtained; through the weighted calculation and comprehensive evaluation of the anti-heavy breakdown gears before and after aging and the difficulty of the aging process, the anti-heavy breakdown level of the test product is obtained.

[0022] Beneficial effects of the present invention:

[0023] 1. The multi-state quantitative evaluation method for the heavy breakdown resistance of vacuum circuit breakers adjusts the pre-breakdown time, closing surge current amplitude and k by changing the test voltage in the closing aging test. By adjusting k, the device can achieve the best aging effect, that is, the aging purpose is achieved without causing contact damage.

[0024] 2. During the test, the multi-state quantitative evaluation method for the anti-destruction performance of the vacuum circuit breaker can adjust the dynamic recovery voltage amplitude or rising rate by changing the test voltage or resistance, and correspondingly change the number of re-breakdown times of the test piece, thereby realizing the adjustment of the breaking aging strength, and evaluate the anti-destruction performance of the test piece by the fastest rising rate when the test piece does not undergo re-breakdown in the high potential area.

[0025] 3. During the closing and aging process, compared with the type test parameters (the test voltage is the phase voltage and the closing surge current is 20kA / 4250Hz), the closing surge current amplitude is appropriately reduced to avoid burning the contacts, and the test voltage is appropriately increased to increase the pre-breakdown time to ensure the aging strength.

[0026] 4. After the test, the method provided by the present invention designs a discharge control circuit, and uses the circuit breaker of the test product to discharge the capacitor bank to ensure the safety of the device. The primary equipment and the secondary equipment are placed in different compartments, and the high and low voltage output ends are connected to the test product through the bushing from the rear panel of the device. Dehumidification and dustproof designs are carried out in the chassis to ensure reliability in different working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a test flow chart of a multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker of the present invention;

[0028] Figure 2 A topological diagram of a primary circuit disconnected and aged in an embodiment of the present invention;

[0029] Figure 3 It is the overall circuit topology diagram of the aging test detection device in the embodiment of the present invention;

[0030] Figure 4 It is the overall measurement and control design scheme of the aging test detection device in the embodiment of the present invention;

[0031] Figure 5 This is a timing diagram of the control of the closing and aging mode of the aging test detection device in the embodiment of the present invention;

[0032] Figure 6 It is a timing diagram of the control of switching on and off the aging mode of the aging test detection device in the embodiment of the present invention;

[0033] Figure 7 This is a timing diagram of the control of the closing + opening aging mode of the aging test detection device in the embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the locking control principle in an embodiment of the present invention;

[0035] Fig. 9 This is a diagram showing the initial test results of each phase of the heavy breakdown resistance of the platform test product in the embodiment of the present invention;

[0036] Fig.10 The comparison results of the heavy breakdown resistance gears of the platform test circuit breaker before and after aging in the embodiment of the present invention are shown;

[0037] Fig.11 This is the aging scoring result of the platform test circuit breaker in the embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0039] Example 1

[0040] This embodiment provides the following technical solutions: a multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker, in which the primary circuit design for closing and breaking aging is first performed, and then the overall test circuit topology of the aging test detection device is integrated and designed, parameter design and device selection are completed, and then secondary measurement, control and protection design are performed, and finally the overall structure design of the device is performed. This embodiment provides the following specific solutions:

[0041] 1. Close and mature circuit design

[0042] Intended to adopt Figure 2 The circuit topology shown in the figure is used for closing aging. Before the test, the circuit breaker SP and the closing circuit control switch GK1 are both in the open state. A large-capacity energy storage capacitor CS1 is used as the closing aging power supply to provide the test voltage and closing surge current. After the closing circuit control switch GK1 is closed, the circuit breaker SP is closed. After the pre-breakdown of the break occurs, CS1 oscillates and discharges through the discharge reactor L, forming a high-frequency and high-current simulation of the closing surge current between the contacts, and the pre-breakdown arc energy is used to close the contacts.

[0043] The resistor divider FY1 is used to monitor the charging voltage of CS1, the Rogowski coil is used to measure the closing inrush current waveform, and the metal oxide voltage limiter MOA is used to limit the overvoltage generated by the test abnormality.

[0044] k is defined as the ratio of the pre-breakdown arc energy in the aging test to the pre-breakdown arc energy under the closing surge current waveform specified in the type test. In the closing aging test, the pre-breakdown time, closing surge current amplitude and k are adjusted by changing the test voltage. By adjusting k, the device can achieve the best aging effect, that is, the aging purpose is achieved without causing contact damage.

[0045] 2. Design of breaking and aging circuit

[0046] Intended to adopt Figure 3The circuit topology shown is used to carry out the evaluation of breaking aging and anti-re-breakdown performance. Before the test, the test circuit breaker SP is in the closed state, and the control switch GK2 is in the open state. A large-capacity energy storage capacitor CS2 is used as the breaking aging power supply to output the breaking aging test voltage. After the breaking circuit control switch GK2 is closed, the test circuit breaker SP is broken without load. CS2 charges the recovery voltage capacitor Ck through the recovery voltage adjustment resistor R1 to form an exponentially rising dynamic recovery voltage applied to the test fracture. After each discharge and arc extinguishing of the fracture, CK can quickly charge the fracture capacitor through the fracture charging resistor R2, so that the fracture voltage is synchronized with the recovery voltage. When the fracture voltage of the test circuit breaker SP continuously exceeds the insulation medium recovery characteristics, multiple re-breakdowns will occur. The insulation of the fracture can be broken and aged by using multiple re-breakdown discharges. The multiple re-breakdown voltage curve can also represent the small current zero arcing time breaking medium recovery characteristic curve of the capacitor bank of SP, which is used to quantitatively evaluate the anti-re-breakdown performance.

[0047] The resistor divider FY2 is used in the test to monitor the CS2 voltage, the resistor dividers FY3 and FY4 are used to measure the recovery voltage and the break voltage waveform respectively, and the metal oxide voltage limiter MOA is used to limit the overvoltage caused by the test abnormality.

[0048] During the test, by changing the test voltage or resistor R1, the dynamic recovery voltage amplitude or rising rate can be adjusted, and the number of re-breakdowns of the test piece can be changed accordingly, thereby adjusting the breaking aging strength. The anti-re-breakdown performance of the test piece can be evaluated by the fastest rising rate when the test piece does not re-breakdown in the high potential area.

[0049] 3. Circuit integration design

[0050] The closing and breaking aging test circuits are integrated to form an aging test detection device. Figure 4 The circuit topology shown in the figure uses a DC high-voltage power supply to charge the energy storage capacitors of the closing and breaking aging circuits at the same time, uses MΩ-level charging resistors RS1 and RS2 to isolate the two circuits and control the charging efficiency, and realizes the switching of the closing aging and breaking aging functions by controlling the opening and closing of switches GK1 and GK2.

[0051] The performance parameters of the designed 12 / 40.5kV aging test detection device are shown in Table 1, and the preliminary selection of devices is shown in Table 2. During the closing aging process, compared with the type test parameters (the test voltage is the phase voltage, and the closing surge current is 20kA / 4250Hz), the closing surge current amplitude is appropriately reduced to avoid burning the contacts, and the test voltage is appropriately increased to increase the pre-breakdown time to ensure the aging strength. During the breaking aging process, the dynamic recovery voltage parameters are designed with reference to the capacitive breaking recovery voltage parameters (the 12 / 40.5kV capacitive TRV peak values ​​are 28 / 95kV, and the rise time is 8.7ms, respectively), and the peak value is appropriately increased and the rise time is accelerated to grasp the capacitive breaking margin of the test product.

[0052] Table 1 Parameter design of the aging test device

[0053]

[0054] Table 2 Main primary components of the aging test device

[0055]

[0056] 4. Secondary measurement and control

[0057] Intended to follow Figure 6 The measurement and control design of the aging test detection device is shown in the figure. The central processor is the core of the measurement and control part. It receives the key electrical parameter measurement data sent by the signal collector and analyzes and calculates it; by issuing instructions to the charging control module, it adjusts the output of the DC charging power supply and controls the closing and breaking of the circuit test voltage; by issuing instructions to the aging test process control module, it controls the closing and breaking of the aging circuit control switches GK1 and GK2, the selection of the resistance value of the breaking aging test recovery voltage adjustment resistor R1, and the closing and breaking of the test circuit breaker SP, so as to realize the control of the three test modes of "closing aging only", "breaking aging only" and "closing + breaking". The preliminary measurement system, control system and data acquisition and processing design are detailed as follows.

[0058] 5. Measurement system

[0059] During the closing and aging process, the energy storage capacitor voltage needs to be measured to control the test voltage, and the closing inrush current of the test product and the current of the test product's opening and closing coils need to be measured to calculate the pre-breakdown energy. During the opening and aging process, the energy storage capacitor voltage needs to be measured to control the test voltage, and the dynamic recovery voltage and the test product's break voltage are used to analyze the test product's re-breakdown process. According to the test parameter design in Table 1, the performance requirements and expected selection of the measuring equipment are preliminarily designed as shown in Table 3. The position of each measuring equipment in the primary circuit is shown in Figure 3 as shown in .

[0060] Table 3 Measuring equipment for the aging test device

[0061]

[0062] 6. Control and protection design

[0063] Experimental model design:

[0064] The burn-in test detection device is planned to be designed with three burn-in modes: "only closing burn-in", "only breaking burn-in" and "closing + breaking burn-in", as follows.

[0065] In the "Only Closing Aging", only high-voltage and large-capacity aging is carried out, and the heavy breakdown resistance performance of the test product is not evaluated. It is suitable for the factory aging of the arc extinguishing chamber. The initial state of each switch is that GK1 and SP are equally divided. During the test, GK1 is closed first, and after GK1 is closed, the test product SP is closed. The action sequence is as follows Figure 5 As shown;

[0066] In "Only Opening and Breaking Aging", only high-voltage spark aging and heavy breakdown resistance performance evaluation are performed, which is suitable for product performance evaluation during circuit breaker acceptance and material sampling inspection, and for initial heavy breakdown resistance performance test before "Closing + Opening and Breaking Aging". The initial state of each switch is GK2 open and SP closed. During the test, GK2 is closed first, and after GK2 is closed, the test product SP is opened as soon as possible. The action sequence is as follows: Figure 6 As shown;

[0067] In the "closing + opening and closing conditioning", the circuit breaker is closed and opened, which not only carries out high-voltage and large-capacity conditioning but also performs heavy breakdown resistance performance evaluation. It is suitable for factory conditioning and on-site operation and maintenance conditioning of circuit breakers. The initial state of each switch is that GK1, GK2 and SP are all open. During the test, the closing and opening time of the test product is controlled to be as short as possible. The action sequence is GK1 closing -> test product SP closing -> closing surge current ends after 20ms -> GK1 opening -> GK2 closing -> test product SP opening as soon as possible. The closing and opening time of the test product can be controlled to be about 0.3s. Figure 7 shown.

[0068] Safety design:

[0069] Electrical interlocking design: The electrical interlocking function is realized by using the normally closed auxiliary contacts of GK1 and GK2. GK1 and GK2 cannot be closed at the same time to prevent the closing circuit and the opening circuit from being put into operation at the same time. The interlocking control principle is as follows: Figure 8 shown.

[0070] Power isolation and grounding: Design reasonable power isolation and grounding methods to ensure the safety of measurement operators and detection devices. The power supply of the main circuit DC charging power supply, the control circuit power supply, and the measurement circuit power supply are kept isolated; use a single-point grounding method, and the ground of each circuit is connected to the earth.

[0071] Capacitor bank discharge operation requirements: When the test device is not performing any operation, the two poles of the capacitor bank are short-circuited to prevent inductive charging and dangerous high voltage at the capacitor terminals; when the test device is maintained and overhauled, use a discharge rod to discharge all terminals to the ground, and reliably hang the discharge rod on the high-voltage terminal; during the test, the device's high-voltage output terminals and the test product terminals are equipped with live display warning lights. After the test, design a discharge control circuit and use the test product circuit breaker to close the circuit to discharge the capacitor bank to ensure the safety of the device.

[0072] 7. Signal processing and parameter calculation

[0073] Signal processing: In order to eliminate the influence of arcing on SP break current signal, SP break voltage signal and SP coil current signal in closing test and breaking test, wavelet transform is first used for filtering according to the basic characteristics of each signal, and the effective data segment is intercepted for closing aging strength calculation and anti-destruction performance evaluation.

[0074] Parameter calculation: According to the collected signals, the estimated breakdown time under phase voltage, the estimated breakdown time under closing voltage, the frequency and amplitude of closing surge current are obtained, and the closing energy and closing energy coefficient are calculated; according to the breaking voltage waveform, the heavy breakdown voltage and time in the high voltage area are obtained, the number of heavy breakdowns in the high voltage area is counted, and the heavy breakdown positions before and after aging, as well as the number of aging times for each position during the aging process are obtained; through the weighted calculation and comprehensive evaluation of the anti-heavy breakdown positions before and after aging and the difficulty of the aging process, the anti-heavy breakdown level of the test product is obtained.

[0075] 8. Overall design

[0076] The 12kV aging test device is proposed to be used as follows Fig. 9 The design shown has dimensions of 2000mm (length) × 1125mm (width) × 1310mm (height), with a net insulation distance of no less than 150mm; the dimensions of the 40.5kV test and detection device are 3000mm (length) × 1800mm (width) × 1980mm (height), with a net insulation distance of no less than 300mm. All test, measurement and control equipment are placed in a chassis with wheels, and the primary and secondary equipment are placed in different compartments. The high and low voltage output ends are connected to the test product through the bushing from the rear panel of the device. Dehumidification and dustproof designs are carried out in the chassis to ensure reliability in different working environments.

[0077] Example 2

[0078] This embodiment provides a comparison of the aging effect of the above-mentioned test and detection device and verification of the heavy breakdown resistance evaluation method. It is planned to carry out the test at a third-party test station with capacitive switching capabilities to verify the aging performance of the test and detection device and test the rationality of the heavy breakdown resistance grading evaluation. The following test plan is adopted:

[0079] 1. Test circuit breaker design

[0080] The test circuit breaker is VS1 / ZN85 type, adopting the design shown in Table 4. When the arc extinguishing chamber leaves the factory, a lightning discharge test is added to the routine factory test to test the insulation level of the break. When the circuit breaker leaves the factory, a routine factory test including mechanical running-in is carried out to record the mechanical characteristics and main circuit resistance.

[0081] Table 4 Test circuit breaker design scheme

[0082]

[0083] 2. Test methods

[0084] Verification of the validity of the test device aging: Select the test circuit breakers in the same state, perform test device aging and test station aging respectively, and verify the validity of the test device aging by comparing the changes in the heavy breakdown resistance level. Test circuit breakers ①, ③ and ⑤ are first subjected to device aging and then to test station aging, while test circuit breakers ② and ④ are first subjected to test station aging and then to device aging.

[0085] Check the rationality of the setting of the heavy breakdown resistance level of the test device: Analyze the rationality of the setting of the heavy breakdown resistance level of the test device based on the passing of test circuit breakers with different heavy breakdown resistance states at the test station.

[0086] 3. Experimental steps

[0087] 3.1 Initial test of heavy breakdown resistance performance of test circuit breakers: All test circuit breakers shall complete heavy breakdown resistance performance test on the aging test device according to the aging test process to obtain the initial state of heavy breakdown resistance performance of the test circuit breaker.

[0088] 3.2 Test device aging performance verification: Test circuit breakers ①, ③ and ⑤, continue the aging test device aging process to complete the aging test and obtain the test device aging performance verification. Test circuit breakers ② and ④ do not perform this step test.

[0089] 3.3 Test station aging of test circuit breakers with different heavy breakdown resistance gears: For all test circuit breakers, aging tests are carried out on the test station aging circuit. According to the test station aging test results of test circuit breakers with different heavy breakdown resistance gears, the effectiveness of the test device aging and the rationality of the heavy breakdown resistance level setting are analyzed.

[0090] 3.4 Retest of heavy breakdown performance of test circuit breakers: All test circuit breakers shall complete heavy breakdown performance test according to the aging process of aging test equipment to obtain the heavy breakdown performance of test circuit breakers.

[0091] 3.5 Test circuit breaker further carries out device aging: Test circuit breakers ② and ④ continue the test device aging process to complete the aging test and further verify the test device aging effect. Test circuit breakers ①, ③ and ⑤ do not carry out this step test.

[0092] 3.6 Return of test circuit breaker to factory and disassembly of arc extinguishing chamber: After the circuit breaker is returned to the factory, the circuit breaker status is checked according to the above-mentioned factory test of circuit breaker and factory test of arc extinguishing chamber, and the arc extinguishing chamber is disassembled and analyzed.

[0093] 4.12kV circuit breaker aging effect comparison and third-party performance verification

[0094] 4.1 Purpose of the test

[0095] Select mainstream models of circuit breakers in operation, install arc extinguishing chambers with different capacitive switching capabilities, and design and process defects in some of them to simulate circuit breakers with different designs and different operating stages. By comparing the difference in capacitive switching capabilities of the same circuit breaker after and without device aging, the performance of the aging device is verified.

[0096] 4.2 Test product design

[0097] A total of 8 test circuit breakers were designed, model VS1, with key parameters: rated voltage 12kV, rated current 1250A, rated short-circuit breaking current 25kA, and rated duration 4s. Two typical arc extinguishing chambers were matched: conventional arc extinguishing chamber and capacitive opening and closing special arc extinguishing chamber, and normal processing and processing with defective contacts were designed respectively to simulate circuit breakers in different states. The test circuit breaker design is shown in Table 5.

[0098] Table 5 Test circuit breaker design

[0099]

[0100]

[0101] 4.3 Test methods

[0102] Table 6 Test methods

[0103]

[0104]

[0105] 4.4 Test results and analysis

[0106] Device aging test results:

[0107] Use the aging test device to carry out aging tests on circuit breakers ①, ③, ⑤, and ⑦. The results are as follows: Fig.11, closing aging voltage 35kV, closing current 3.6kA / 3.6kHz, pre-breakdown arc energy 33.75-63.66%, breaking aging voltage 35kV, dynamic recovery voltage level 5. The test analysis is as follows:

[0108] Circuit breakers with conventional arc extinguishing chambers: After aging, the heavy breakdown resistance level increased to 3-5 levels, 16.7% were 5 levels, 66.7% were 4 levels, and 16.7% were 3 levels, and most of them were at a good level of heavy breakdown resistance. Circuit breakers with normally processed arc extinguishing chambers had an average heavy breakdown resistance level of 3.67 levels after aging, an average increase of 2.33 levels, and an average aging score of 71.3; circuit breakers with processed arc extinguishing chambers with defects had an average heavy breakdown resistance level of 4.33 levels after aging, an average increase of 3.67 levels, and an average aging score of 72.7. This shows that device aging is more effective in eliminating processing defects.

[0109] Circuit breakers equipped with capacitive opening and closing arc extinguishing chambers: after aging, the heavy breakdown resistance level is increased to 4-5 levels, 16.7% is 5 levels, and 83.3% is 4 levels, both of which are at a good level of heavy breakdown resistance. Circuit breakers equipped with normally processed arc extinguishing chambers have an average heavy breakdown resistance level of 4.33 levels after aging, an average increase of 3 levels, and an average aging score of 78.3; circuit breakers equipped with defective arc extinguishing chambers after aging have an average heavy breakdown resistance level of 4 levels, an average increase of 3 levels, and an average aging score of 72. This shows that arc-melted contacts are dense and have good ablation resistance. Factory aging is not enough to eliminate processing defects, and the aging effect of the device is obvious.

[0110] Comprehensive analysis shows that factory aging has a certain effect on improving the heavy breakdown resistance of conventional arc extinguishing chambers in normal processing, and the effect on capacitive opening and closing arc extinguishing chambers is uneven. There is no obvious effect on arc extinguishing chambers with processing defects. After the device is aging, the gear of most arc extinguishing chambers can be increased to gear 4-5.

[0111] The main circuit resistance is almost unchanged before and after aging, and the pre-breakdown time remains unchanged or shortened, which further indicates that the insulation performance of the contact gap is improved after aging.

[0112] The burn-in rating takes into account the test piece's pre-burn-in position, post-burn-in position, and the number of re-breakdowns during burn-in. The burn-in position after burn-in is the main factor (weighted 70%), and the pre-burn-in position is the secondary factor (weighted 30%). The number of re-breakdowns during burn-in is a deduction item, and the more times, the more points are deducted. The rating results show that most arc extinguishing chambers are at excellent or good levels. The normally processed capacitive opening and closing arc extinguishing chamber scored the highest, and the conventional arc extinguishing chamber scored lower, which is consistent with the actual project. The main reason for the low score of the capacitive opening and closing arc extinguishing chamber with processing defects is the low pre-burn-in position.

[0113] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

[0114] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker, characterized in that: The following steps are involved: Step 1: Design a closed and aged primary circuit; Step 2: Design a primary circuit for breaking and aging; Step 3: Integrated design of the overall test loop topology of the aging test and detection device; Step 4: Perform parameter design and device selection; Step 5: Conduct secondary measurement; Step 6: Control and protection design, signal processing and parameter calculation; Step 7: Design the overall structure of the device.

2. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 1, characterized in that: In the step 1, before the test, the test circuit breaker and the closing loop control switch are both in the open state, and a large-capacity energy storage capacitor is used as a closing aging power supply to provide a test voltage and a closing surge current. After the closing loop control switch is closed, the test circuit breaker performs a closing operation, and after a pre-breakdown occurs at the break, an oscillation discharge is performed through the discharge reactor to form a high-frequency and large-current simulation of a closing surge current between the contacts, and the pre-breakdown arc energy is used to perform closing aging on the contacts.

3. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 2, characterized in that: In the closing aging test, the pre-breakdown time, the closing surge current amplitude and the ratio of the pre-breakdown arc energy in the aging test to the pre-breakdown arc energy under the closing surge current waveform specified in the type test are adjusted by changing the test voltage. The best aging effect of the device is achieved by adjusting the ratio of the pre-breakdown arc energy.

4. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 1, characterized in that: In the step 2, before the test, the test circuit breaker is in the closed state, the control switch is in the open state, a large-capacity energy storage capacitor is used as the breaking aging power supply, and the breaking aging test voltage is output. After the breaking circuit control switch is closed, the test circuit breaker is broken at no load, and the large-capacity energy storage capacitor charges the recovery voltage capacitor through the recovery voltage regulating resistor to form an exponentially rising dynamic recovery voltage applied to the test fracture. After each discharge and arc extinguishing of the fracture, the breaking circuit control switch can quickly charge the fracture capacitor through the fracture charging resistor to synchronize the fracture voltage with the recovery voltage. When the fracture voltage of the test circuit breaker continuously exceeds the recovery characteristics of the insulating medium, multiple re-breakdowns will occur. The insulation of the fracture can be broken and aged by using multiple re-breakdown discharges. The multiple re-breakdown voltage curves can also represent the small current zero arcing time breaking medium recovery characteristic curve of the capacitor group of the test circuit breaker, which is used to quantitatively evaluate the anti-re-breakdown performance.

5. A multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker according to claim 4, characterized in that: During the test, by changing the test voltage or resistance, adjusting the dynamic recovery voltage amplitude or rising rate, the number of re-breakdown times of the test piece can be changed accordingly, and the breaking aging strength can be adjusted. The anti-re-breakdown performance of the test piece can be evaluated by the fastest rising rate when no re-breakdown occurs in the high potential area of ​​the test piece.

6. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 1, characterized in that: In the step three, a DC high-voltage power supply is used to charge the energy storage capacitors of the closing and opening aging circuits at the same time, and a MΩ-level charging resistor is used to isolate the circuit and control the charging efficiency, and the closing and opening aging functions are switched by controlling the opening and closing of the switch.

7. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 1, characterized in that: In the step 5, by issuing instructions to the charging control module, the output of the DC charging power supply is adjusted to control the closing and opening of the circuit test voltage; by issuing instructions to the aging test process control module, the closing and opening of the aging circuit control switch, the selection of the resistance value of the aging test recovery voltage adjustment resistor, and the closing and opening of the test circuit breaker are controlled to realize the control of the three test modes of "closing aging only", "opening aging only" and "closing + opening".

8. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 1, characterized in that: The control and protection design includes three training modes: "only closing training", "only breaking training" and "closing + breaking training". The protection design also includes safety design, and the safety design includes electrical interlocking design, power isolation and grounding, and container group discharge operation requirements.

9. A multi-state quantitative evaluation method for the heavy breakdown resistance performance of a vacuum circuit breaker according to claim 8, characterized in that: Signal processing is used to eliminate the influence of arcing on the test circuit breaker break current signal, test circuit breaker break voltage signal, and test circuit breaker coil current signal during closing and breaking tests. According to the basic characteristics of each signal, wavelet transform is first used for filtering, and the effective data segment is intercepted for closing aging strength calculation and anti-destruction performance evaluation.

10. A multi-state quantitative evaluation method for the heavy breakdown resistance of a vacuum circuit breaker according to claim 9, characterized in that: Parameter calculation: Based on the collected signals, the estimated breakdown time under phase voltage, the estimated breakdown time under closing voltage, the frequency and amplitude of closing surge current are obtained, and the closing energy and closing energy coefficient are calculated. According to the breaking voltage waveform, the heavy breakdown voltage and time in the high voltage area are obtained, the number of heavy breakdowns in the high voltage area is counted, and the heavy breakdown positions before and after aging, as well as the number of aging times for each position during the aging process are obtained. Through the weighted calculation and comprehensive evaluation of the anti-heavy breakdown positions before and after aging and the difficulty of the aging process, the anti-heavy breakdown level of the test product is obtained.

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