T00a test loop and method for high-voltage circuit breaker under high asymmetry degree working condition

Abstract

The invention discloses a T00a test loop and method for a high-voltage circuit breaker under a high asymmetry degree working condition, and the test loop comprises a current source which is connected in series with a tested circuit breaker TO to form a first loop; the first voltage source, the second voltage source and the third voltage source are connected in series with the tested circuit breaker TO to form a second loop; and the plurality of auxiliary switch mechanisms are arranged on the second loop. The stable current is provided through the current source, the current condition of the high-voltage circuit breaker under the actual working condition can be simulated, the performance of the high-voltage circuit breaker can be evaluated more accurately, the diversity and adjustability of the voltage source enable the test loop to simulate different voltage conditions, the accuracy and practicability of the test are further improved, and the test efficiency is improved. And the requirements for the TRV peak value and the power frequency recovery voltage in the standard can be met at the same time, and compared with a two-gear test in a traditional step-by-step method, the test loop only needs a one-gear test, so that the test efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage AC circuit breaker large-capacity testing, and in particular relates to a T00a test circuit and method for a high-voltage circuit breaker under highly asymmetric working conditions. Background Art

[0002] Large capacity test is a general term for the test of the breaking and closing ability of high-voltage switchgear and the ability of some high-voltage electrical equipment to withstand high voltage and high current with a high-power power supply. It includes basic short-circuit test, single-phase and out-of-phase ground fault test, near-zone fault test, out-of-step closing and breaking test, capacitive current opening and closing test, short-time withstand current and peak withstand current test, etc. High-voltage switchgear refers to circuit breakers and disconnectors. AC high-voltage circuit breakers are the main power control equipment of substations. When the system is operating normally, they can cut off and connect the no-load and load current of lines and various electrical equipment; when the system fails, it cooperates with relay protection to quickly cut off the fault current to prevent the expansion of the accident scope. Therefore, the performance of high-voltage circuit breakers directly affects the safe operation of the power system. The time constant is determined by the ratio of reactance to resistance of the power system. GB 1984-2014 High Voltage AC Circuit Breakers stipulates that the standard value of the DC time constant for the rated short-circuit breaking current is 45 ms, and provides the DC time constant under special working conditions related to the rated voltage of the circuit breaker: 120 ms for rated voltages of 40.5 kV and below; 60 ms for rated voltages of 72.5 kV to 363 kV; 75 ms for rated voltages of 550 kV to 800 kV; 100, 120 ms for rated voltages of 1,100 kV. In addition, higher values ​​may be required for certain special purposes. GB, IEC and DL standards all state in the notes that for circuit breakers close to generators, the time constant may be required to be higher.

[0003] For a circuit breaker with a rated voltage of 1100kV, the time constant is usually 120ms. When a fault occurs in the power system, the fault must be quickly removed to ensure the stability of the system. When the time constant of the primary system is 120ms, the DC component decays more slowly than when the time constant is 45ms, the DC component of the short-circuit current is high at the time of breaking, and it is difficult for the circuit breaker to break T00a. When the time constant of the DC component increases, the effective value of the short-circuit current and the arcing time will increase. Although TRV decreases, the influencing factors of arc energy still dominate when breaking, so the comprehensive breaking conditions still become harsh. In the laboratory, the T00a test is carried out. Under the condition of a time constant of 120ms, the peak value of the transient recovery voltage of the first opening pole is usually lower than the peak value of the power frequency voltage. For the UHV circuit breaker laboratory, the T00a test is usually carried out using a synthetic test method. The recovery voltage provided by this method is an attenuated AC recovery voltage. Therefore, when the TRV peak meets the standard requirements, its power frequency recovery voltage is much lower than the power frequency recovery voltage specified in the standard.

[0004] At present, the test is carried out in a step-by-step manner, that is, for circuit breakers used under the working condition of a time constant of 120ms, T00a is completed using two tests. The first test is for the first and last pole opening tests, the TRV peak meets the standard requirements, and the power frequency recovery voltage is lower than the standard requirements. The second test does not require TRV, the power frequency recovery voltage meets the standard requirements, and the arcing time of the first and last pole opening is consistent with the first test.

[0005] The above method has its shortcomings in practical applications. In actual working conditions, TRV peak value and power frequency recovery voltage are two main parameters of the same recovery voltage waveform. Ideally, they should be evaluated at the same time. The above technical solution evaluates TRV peak value and power frequency recovery voltage parameters separately, which cannot be completely equivalent to the actual working conditions, and the test method cannot accurately reflect the test situation. Summary of the invention

[0006] The purpose of the present invention is to provide a T00a test circuit and method for high-voltage circuit breakers under highly asymmetric conditions, so as to solve the technical defects in the prior art that the TRV peak value and the power frequency recovery voltage parameters are assessed separately, which cannot be completely equivalent to the actual working conditions and the test method cannot accurately reflect the test situation.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a T00a test circuit for a high-voltage circuit breaker under a high asymmetry condition is provided, comprising: The current source is connected in series with the circuit breaker TO under test to form the first circuit; The first voltage source, the second voltage source and the third voltage source are connected in series with the circuit breaker TO under test to form a second circuit; A plurality of auxiliary switch mechanisms are arranged on the second circuit.

[0008] Furthermore, the current source includes an impulse generator G, a protection switch GB, a closing switch MS, an operating switch MB, a reactor LT, a transformer PT, a capacitor C01, a resistor R01 and an arc extension device AP; The impulse generator G is connected in series with the protection switch GB, the closing switch MS, the operating switch MB, the reactor LT and the low-voltage winding of the transformer PT; The high voltage winding of the transformer PT is connected in series with the arc extension device AP.

[0009] Furthermore, the capacitor C01 and the resistor R01 are connected in series, and the high-voltage winding of the transformer PT is also connected in parallel with the loop formed by connecting the capacitor C01 and the resistor R01 in series.

[0010] Furthermore, the auxiliary switch mechanism includes a second auxiliary switch AB2, and the first voltage source is connected in series with the second auxiliary switch AB2.

[0011] Further, the first voltage source includes a main capacitor Cs1, a ignition ball GP1, R1 and C1, one end of the main capacitor Cs1 is connected to one end of the ignition ball GP1, and the other end of the main capacitor Cs1 is divided into two paths, one path is connected to one end of C1, and the second path is connected to the current I; The other end of the ignition ball GP1 is also divided into two paths, one path is connected to the other end of C1 through R1, and the second path is connected to the second auxiliary switch AB2 through R1.

[0012] Furthermore, the auxiliary switch mechanism further includes a fourth auxiliary switch AB4, and the second voltage source is connected in series with the fourth auxiliary switch AB4.

[0013] Furthermore, the second voltage source includes a main capacitor Cs2, a ignition ball GP2 and a frequency modulation branch. One end of the main capacitor Cs2 is connected to one end of the ignition ball GP2, and the other end is connected to one end of the frequency modulation branch, and the other end of the ignition ball GP2 is connected to the other end of the frequency modulation branch.

[0014] Furthermore, the frequency modulation branch includes L1, Ls1, R2, C2, R4 and a time delay capacitor Cd2; One end of L1 is divided into four paths, the first path is connected to one end of the delay capacitor Cd2, and the delay capacitor Cd2 is connected to one end of the main capacitor Cs2; The second path of L1 is connected to one end of Ls1, and the third path is connected to R2 via Ls1 and R4; The fourth path of L1 is connected to one end of C2 via Ls1, R4 and R2; The other end of L1 is divided into two paths, the first path is connected to the other end of the main capacitor Cs2, and the second path is connected to the other end of C2.

[0015] Further, the third voltage source includes a main capacitor Cs3, an ignition ball GP3, L2, Ls2, R3, C3, R5 and a delay capacitor Cd1, and the auxiliary switch mechanism includes a fifth auxiliary switch AB5; One end of the main capacitor Cs3 is connected to one end of the ignition ball GP3, and the other end of the main capacitor Cs3 is divided into three paths, the first path is connected to the first path of one end of L2, the second path is connected to one end of C3, and the third path is connected to one end of the delay capacitor Cd1; The other end of the ignition ball GP3 is divided into two paths, the first path is connected to one end of the fifth auxiliary switch AB5, and the second path is connected to one end of Ls2; The other end of the fifth auxiliary switch ABS is connected to the other end of L2, the other end of Ls2 is connected to one end of R5, the other end of R5 has two paths, the first path is connected to the first path of one end of R3, and the other end of R3 is connected to the other end of C3; The second path at one end of L2 is connected to the other end of C3, and the other end of the delay capacitor Cd1 is divided into two paths, the first path is connected to the second path at the other end of R5, and the second path is connected to the second path at one end of R3.

[0016] In a second aspect, a T00a method for a high-voltage circuit breaker under a high asymmetry condition is provided, the method being performed using the test circuit as described above, comprising: Put the current source, auxiliary switch mechanism and the circuit breaker under test TO in the closed state so that each voltage source is in the charging state; After the current flows for a period of time, the auxiliary switch mechanism and the circuit breaker under test TO are disconnected at the same zero point of the current; Control the ignition ball GP3 to ignite, connect the third voltage source to one end of the circuit breaker TO under test, so that the circuit breaker is in an arcing state, and the third voltage source generates a high-frequency current; The auxiliary switch mechanism is separated when the power frequency current of the second voltage source passes through the first zero point, and the second voltage source is short-circuited. After waiting for a period of time, the auxiliary switch mechanism is closed to restore the power frequency voltage of the tested circuit breaker after it is disconnected.

[0017] Compared with the prior art, the present invention has the following beneficial effects: By providing a stable current through the current source, the current conditions of the high-voltage circuit breaker under actual working conditions can be simulated, so as to more accurately evaluate its performance. The diversity and adjustability of the voltage source enable the test circuit to simulate different voltage conditions, further improving the accuracy and practicality of the test, and can simultaneously meet the requirements of the standard for TRV peak and power frequency recovery voltage. Compared with the traditional step-by-step method with two-level test, this test circuit only needs one level test, which improves the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of the structure of a T00a test circuit for a high-voltage circuit breaker under highly asymmetric working conditions provided by the present invention; Figure 2 A flow chart of the T00a test method for a high-voltage circuit breaker under high asymmetry conditions provided by the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0024] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] Large capacity test is a general term for the test of the breaking and closing ability of high-voltage switchgear and the ability of some high-voltage electrical equipment to withstand high voltage and high current with a high-power power supply. It includes basic short-circuit test, single-phase and out-of-phase ground fault test, near-zone fault test, out-of-step closing and breaking test, capacitive current opening and closing test, short-time withstand current and peak withstand current test, etc. High-voltage switchgear refers to circuit breakers and disconnectors. AC high-voltage circuit breakers are the main power control equipment of substations. When the system is operating normally, they can cut off and connect the no-load and load current of lines and various electrical equipment; when the system fails, it cooperates with relay protection to quickly cut off the fault current to prevent the expansion of the accident scope. Therefore, the performance of high-voltage circuit breakers directly affects the safe operation of the power system. The time constant is determined by the ratio of reactance to resistance of the power system. GB 1984-2014 High Voltage AC Circuit Breakers stipulates that the standard value of the DC time constant for the rated short-circuit breaking current is 45 ms, and provides the DC time constant under special working conditions related to the rated voltage of the circuit breaker: 120 ms for rated voltages of 40.5 kV and below; 60 ms for rated voltages of 72.5 kV to 363 kV; 75 ms for rated voltages of 550 kV to 800 kV; 100, 120 ms for rated voltages of 1,100 kV. In addition, higher values ​​may be required for certain special purposes. GB, IEC and DL standards all state in the notes that for circuit breakers close to generators, the time constant may be required to be higher.

[0026] For a circuit breaker with a rated voltage of 1100kV, the time constant is usually 120ms. When a fault occurs in the power system, the fault must be quickly removed to ensure the stability of the system. When the time constant of the primary system is 120ms, the DC component decays more slowly than when the time constant is 45ms, the DC component of the short-circuit current is high at the time of breaking, and it is difficult for the circuit breaker to break T00a. When the time constant of the DC component increases, the effective value of the short-circuit current and the arcing time will increase. Although TRV decreases, the influencing factors of arc energy still dominate when breaking, so the comprehensive breaking conditions still become harsh. In the laboratory, the T00a test is carried out. Under the condition of a time constant of 120ms, the peak value of the transient recovery voltage of the first opening pole is usually lower than the peak value of the power frequency voltage. For the UHV circuit breaker laboratory, the T00a test is usually carried out using a synthetic test method. The recovery voltage provided by this method is an attenuated AC recovery voltage. Therefore, when the TRV peak meets the standard requirements, its power frequency recovery voltage is much lower than the power frequency recovery voltage specified in the standard.

[0027] At present, the test is carried out in a step-by-step manner, that is, for circuit breakers used under the working condition of a time constant of 120ms, T00a is completed using two tests. The first test is for the first and last pole opening tests, the TRV peak meets the standard requirements, and the power frequency recovery voltage is lower than the standard requirements. The second test does not require TRV, the power frequency recovery voltage meets the standard requirements, and the arcing time of the first and last pole opening is consistent with the first test.

[0028] The above method has its shortcomings in practical applications. In actual working conditions, TRV peak value and power frequency recovery voltage are two main parameters of the same recovery voltage waveform. Ideally, they should be evaluated at the same time. The above technical solution evaluates TRV peak value and power frequency recovery voltage parameters separately, which cannot be completely equivalent to the actual working conditions, and the test method cannot accurately reflect the test situation.

[0029] In order to solve the above technical defects, the inventor provides a T00a test circuit and method for high-voltage circuit breaker under high asymmetry conditions.

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings: First, as Figure 1-As shown, an embodiment of the present invention provides a T00a test circuit for a high-voltage circuit breaker under a high asymmetry condition, including a current source, which is connected in series with the tested circuit breaker TO to form a first circuit, and the current source is used to provide a stable current to simulate the current conditions under actual working conditions; a first voltage source, a second voltage source and a third voltage source are connected in series with the tested circuit breaker TO to form a second circuit, which is used to provide different voltage conditions to test the performance of the circuit breaker under different voltages; a plurality of auxiliary switch mechanisms are arranged on the second circuit to control the on-off of the circuit and switch different voltage conditions. In the process of using this circuit test, a stable current is provided by the current source, which can simulate the current conditions of the high-voltage circuit breaker under actual working conditions, so as to more accurately evaluate its performance, and the diversity and adjustability of multiple voltage sources enable the test circuit to simulate different voltage conditions, further improve the accuracy and practicality of the test, and can simultaneously meet the requirements of the standard for TRV peak value and power frequency recovery voltage. Compared with the traditional step-by-step method using two-stage test, this test circuit only needs one-stage test, which improves the test efficiency.

[0031] like Figure 1As shown, the current source includes an impulse generator G, a protection switch GB, a closing switch MS, an operating switch MB, a reactor LT, a transformer PT, a capacitor C01, a resistor R01 and an extension device AP; wherein the impulse generator G is connected in series with the protection switch GB, the closing switch MS, the operating switch MB, the reactor LT and the low-voltage winding of the transformer PT, and the high-voltage winding of the transformer PT is connected in series with the extension device AP. As a key device for high-voltage circuit breaker testing, the impulse generator G can simulate the high-voltage and high-current conditions under actual working conditions to ensure the accuracy and authenticity of the test. During the test, the protection switch GB can monitor the circuit status in real time. Once an abnormality or fault is detected, the circuit is immediately cut off to protect the test equipment and the circuit breaker under test from damage, which not only improves the safety of the test, but also ensures the reliability of the test results. The reactor LT is used to adjust the inductive load in the circuit, and cooperates with the transformer PT to achieve precise control of the test voltage and current; the transformer PT is used to convert the high-voltage current into a low-voltage current for subsequent measurement and analysis. The setting of the closing switch MS and the operating switch MB enables the test personnel to conveniently control the on and off of the circuit and switch different test conditions. Through reasonable operation sequence and timing control, the test process can be optimized, the number and time of repeated tests can be reduced, and the test efficiency can be improved. Capacitor C01 and resistor R01 are used to adjust the reactive power and active power in the circuit to achieve further precise control of the test conditions, which helps to ensure the accuracy and consistency of the test results, and also helps to improve the test efficiency. The arc extension device AP can adjust the duration of the arc to ensure the stability and controllability of the arc during the test. By connecting it in series with the high-voltage winding of the transformer PT, the voltage and current applied to the circuit breaker can be accurately controlled, so as to more accurately simulate the arc conditions under actual working conditions. Further, capacitor C01 and resistor R01 are connected in series, and the high-voltage winding of the transformer PT is also connected in parallel with the circuit in which capacitor C01 and resistor R01 are connected in series. Capacitor C01 plays a filtering role in the circuit, which can absorb and release electrical energy, thereby smoothing the voltage fluctuation in the circuit, which helps to reduce the error caused by voltage fluctuation during the test and improve the accuracy of the test data. Resistor R01 acts as a damper in the circuit, consuming electrical energy, thereby suppressing circuit oscillations, helping to stabilize the current and voltage waveforms in the test circuit and making the test process more stable. During the test, if an abnormal situation such as overcurrent or overvoltage occurs in the circuit, the circuit in which capacitor C01 and resistor R01 are connected in series can absorb and consume excess electrical energy, thus protecting the transformer PT from damage and extending its service life.By adjusting the values ​​of capacitor C01 and resistor R01, the voltage and current waveforms in the test circuit can be flexibly adjusted, which can also meet the needs under different test conditions and improve the flexibility and applicability of the test; and the circuit in which capacitor C01 and resistor R01 are connected in series can reduce energy loss during the test, improve test efficiency, help shorten the test cycle, and reduce test costs. Figure 1 As shown, the auxiliary switch mechanism includes a second auxiliary switch AB2, and the first voltage source is connected in series with the second auxiliary switch AB2. Through the on-off control of the second auxiliary switch AB2, it is convenient to switch whether the first voltage source is connected to the test circuit, so that the test personnel can flexibly choose whether to apply the voltage of the first voltage source according to different test requirements, thereby improving the flexibility of the test. The series use of the second auxiliary switch AB2 allows the voltage of the first voltage source to be accurately controlled. By adjusting the degree of closure of the second auxiliary switch AB2 or selecting different types of switches, the voltage can be accurately adjusted to meet the precise requirements of the test for voltage conditions. During the test, if the voltage of the first voltage source is too high or the test circuit fails, the second auxiliary switch AB2 can cut off the circuit in time to protect the test equipment from damage, reduce the safety risks during the test, and ensure the smooth progress of the test. Furthermore, the first voltage source includes a main capacitor Cs1, an ignition ball GP1, R1 and C1, one end of the main capacitor Cs1 is connected to one end of the ignition ball GP1, and the other end of the main capacitor Cs1 is divided into two paths, one path is connected to one end of C1, and the second path is connected to the current I; the other end of the ignition ball GP1 is also divided into two paths, one path is connected to the other end of C1 through R1, and the second path is connected to the second auxiliary switch AB2 through R1. As an energy storage element, the main capacitor Cs1 can accumulate a large amount of electrical energy during the charging process. When discharge is required, the main capacitor Cs1 quickly releases electrical energy through the ignition ball GP1 to form a high-voltage pulse, and the combination of resistor R1 and capacitor C1 plays a role in regulating and stabilizing the discharge process, ensuring the stability and reliability of the voltage source. Secondly, as a discharge gap, the ignition ball GP1 can quickly break down and conduct current under high voltage. Its stable breakdown voltage and fast conduction characteristics help to improve the stability and response speed of the voltage source. Figure 1As shown, the auxiliary switch mechanism also includes a fourth auxiliary switch AB4, a second voltage source is connected in series with the fourth auxiliary switch AB4, the second voltage source includes a main capacitor Cs2, an ignition ball GP2 and a frequency modulation branch, one end of the main capacitor Cs2 is connected to one end of the ignition ball GP2, and the other end is connected to one end of the frequency modulation branch, and the other end of the ignition ball GP2 is connected to the other end of the frequency modulation branch. The frequency modulation branch includes L1, Ls1, R2, C2, R4 and a delay capacitor Cd2; one end of L1 is divided into four paths, the first path is connected to one end of the delay capacitor Cd2, and the delay capacitor Cd2 is connected to one end of the main capacitor Cs2; the second path of L1 is connected to one end of Ls1, and the third path is connected to R2 through Ls1 and R4; the fourth path of L1 is connected to one end of C2 through Ls1, R4 and R2; the other end of L1 is divided into two paths, the first path is connected to the other end of the main capacitor Cs2, and the second path is connected to the other end of C2. The inductors L1, Ls1, resistors R2, R4 and time-delay capacitor Cd2 in the frequency modulation branch together constitute a frequency modulation circuit, which can adjust the output frequency of the second voltage source. By adjusting the component parameters in the frequency modulation branch, the output frequency can be precisely controlled to meet the frequency requirements under different test conditions. The main capacitor Cs2, as an energy storage element, can accumulate a large amount of electrical energy during the charging process. When discharge is required, the on-off control of the fourth auxiliary switch AB4 can accurately control the start and end of the discharge process. The ignition ball GP2, as a discharge gap, can quickly break down and conduct current under high voltage, and cooperate with the frequency modulation branch to achieve precise control of the discharge process. Figure 1 As shown, the third voltage source includes a main capacitor Cs3, an ignition ball GP3, L2, Ls2, R3, C3, R5 and a time-delay capacitor Cd1, and the auxiliary switch mechanism includes a fifth auxiliary switch AB5; one end of the main capacitor Cs3 is connected to one end of the ignition ball GP3, and the other end of the main capacitor Cs3 is divided into three paths, the first path is connected to the first path at one end of L2, the second path is connected to one end of C3, and the third path is connected to one end of the time-delay capacitor Cd1; the other end of the ignition ball GP3 is divided into two paths, the first path is connected to one end of the fifth auxiliary switch AB5, and the second path is connected to one end of Ls2; the other end of the fifth auxiliary switch ABS is connected to the other end of L2, the other end of Ls2 is connected to one end of R5, and the other end of R5 is respectively connected to two paths, the first path is connected to the first path at one end of R3, and the other end of R3 is connected to the other end of C3; The second path at one end of L2 is connected to the other end of C3, and the other end of the time-delay capacitor Cd1 is divided into two paths, the first path is connected to the second path at the other end of R5, and the second path is connected to the second path at one end of R3. The auxiliary switch mechanism includes a fifth auxiliary switch AB5, and the fifth auxiliary switch AB5 is connected in series with the third power source. In this process, the addition of the time-delay capacitor Cd1 makes the discharge process of the voltage source have a certain time delay characteristic, and this time delay characteristic can be used to adjust the start time of the discharge process, thereby realizing accurate control of the discharge process. The series use of the fifth auxiliary switch AB5 provides an additional control point for the on-off of the voltage source. By controlling the on-off of the switch, the connection and disconnection of the voltage source can be flexibly controlled, thereby realizing accurate control of the test process.

[0032] In a second aspect, this embodiment provides a T00a test method for a high voltage circuit breaker under a high asymmetry condition, wherein the method is performed using the test circuit as described above. Figure 2 As shown, including: S101. The current source, the auxiliary switch mechanism and the circuit breaker under test TO are in the closed state so that each voltage source is in the charging complete state; illustratively, at the beginning of the test, the protection switch GB, the closing switch MS, the operating switch MB, the auxiliary switches AB1, AB3, AB4 and the test product TO are in the closed state; the auxiliary switch mechanism includes a first auxiliary switch AB1, a second auxiliary switch AB2, a third auxiliary switch AB3 and a fourth auxiliary switch AB4; wherein, during this process, the second auxiliary switch AB2 and the fifth auxiliary switch AB5 are in the opening state; at this time, the test product is only connected to the current source loop and bears the short-circuit current, and the first voltage source, the second voltage source and the third voltage source are in the charging complete state.

[0033] S102, after the current flows for a period of time, the auxiliary switch mechanism and the circuit breaker under test TO are disconnected at the same zero point of the current; illustratively, after the current flows for a period of time (such as 50ms~100ms), the first auxiliary switch AB1, the third auxiliary switch AB3 and the test product TO are controlled to be disconnected at the same zero point of the current, in a very short time (about 100us-1.6ms) before the current source current flows.

[0034] S103, control the ignition ball GP3 to ignite, connect the third voltage source to one end of the test circuit breaker TO, so that the circuit breaker is in an arcing state, and the third voltage source generates a high-frequency current; illustratively, control the ignition ball GP3 to ignite the switch, and the third voltage source is put into operation at one end of the test product TO. At this time, the circuit breaker is in an arcing state, and the third voltage source generates a high-frequency current. The currents provided by the third voltage source and the current source flow through the test circuit breaker TO together. After the test circuit breaker breaks the current, the third voltage source establishes a recovery voltage. After a few hundred microseconds when the recovery voltage begins to be established, the second voltage source is put into operation to apply the recovery voltage to one end of the test product TO. At this time, there are only two sets of voltage sources acting on both ends of the test product TO, and the second voltage source and the third voltage source work together to provide TRV after the test circuit breaker is broken.

[0035] S104 separates the auxiliary switch mechanism at the first zero crossing of the power frequency current of the second voltage source, short-circuits the second voltage source, and after waiting for a period of time, closes the auxiliary switch mechanism to restore the power frequency voltage after the circuit breaker under test is disconnected. For example, at the first zero crossing of the power frequency current of the second voltage source, the fourth auxiliary switch AB4 separates, the second voltage source is disconnected, and after 50us, the second auxiliary switch AB2 and the fifth auxiliary AB5 are closed at the same time, the ignition ball GP1 is ignited, the first voltage source is put into operation, and the first voltage source and the third voltage source jointly provide the power frequency recovery voltage after the circuit breaker under test is disconnected. By providing a stable current through the current source, the current condition of the high-voltage circuit breaker under actual working conditions can be simulated, so as to more accurately evaluate its performance, and the diversity and adjustability of the voltage source enable the test circuit to simulate different voltage conditions, further improving the accuracy and practicality of the test, and can simultaneously meet the requirements of the standard for TRV peak value and power frequency recovery voltage. Compared with the traditional step-by-step method using two-stage tests, this test circuit only needs one-stage test, which improves the test efficiency.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A T00a test circuit for high-voltage circuit breakers under highly asymmetric conditions, characterized in that: include: The current source is connected in series with the circuit breaker TO under test to form the first circuit; The first voltage source, the second voltage source and the third voltage source are connected in series with the circuit breaker TO under test to form a second circuit; A plurality of auxiliary switch mechanisms are arranged on the second circuit.

2. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 1 is characterized in that: The current source includes an impulse generator G, a protection switch GB, a closing switch MS, an operating switch MB, a reactor LT, a transformer PT, a capacitor C01, a resistor R01 and an arc extension device AP; The impulse generator G is connected in series with the protection switch GB, the closing switch MS, the operating switch MB, the reactor LT and the low-voltage winding of the transformer PT; The high voltage winding of the transformer PT is connected in series with the arc extension device AP.

3. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 2, characterized in that: The capacitor C01 and the resistor R01 are connected in series, and the high-voltage winding of the transformer PT is also connected in parallel with the loop formed by the series connection of the capacitor C01 and the resistor R01.

4. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 1, characterized in that: The auxiliary switch mechanism includes a second auxiliary switch AB2 , and the first voltage source is connected in series with the second auxiliary switch AB2 .

5. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 4, characterized in that: The first voltage source includes a main capacitor Cs1, a ignition ball GP1, R1 and C1, one end of the main capacitor Cs1 is connected to one end of the ignition ball GP1, and the other end of the main capacitor Cs1 is divided into two paths, one path is connected to one end of C1, and the second path is connected to the current I; The other end of the ignition ball GP1 is also divided into two paths, one path is connected to the other end of C1 through R1, and the second path is connected to the second auxiliary switch AB2 through R1.

6. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 1, characterized in that: The auxiliary switch mechanism further includes a fourth auxiliary switch AB4 , and the second voltage source is connected in series with the fourth auxiliary switch AB4 .

7. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 6, characterized in that: The second voltage source includes a main capacitor Cs2, a ignition ball GP2 and a frequency modulation branch. One end of the main capacitor Cs2 is connected to one end of the ignition ball GP2, and the other end is connected to one end of the frequency modulation branch, and the other end of the ignition ball GP2 is connected to the other end of the frequency modulation branch.

8. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 7, characterized in that: The frequency modulation branch includes L1, Ls1, R2, C2, R4 and a time delay capacitor Cd2; One end of L1 is divided into four paths, the first path is connected to one end of the delay capacitor Cd2, and the delay capacitor Cd2 is connected to one end of the main capacitor Cs2; The second path of L1 is connected to one end of Ls1, and the third path is connected to R2 via Ls1 and R4; The fourth path of L1 is connected to one end of C2 via Ls1, R4 and R2; The other end of L1 is divided into two paths, the first path is connected to the other end of the main capacitor Cs2, and the second path is connected to the other end of C2.

9. The T00a test circuit for high-voltage circuit breaker under high asymmetry conditions according to claim 1, characterized in that: The third voltage source includes a main capacitor Cs3, a ignition ball GP3, L2, Ls2, R3, C3, R5 and a delay capacitor Cd1, and the auxiliary switch mechanism includes a fifth auxiliary switch AB5; One end of the main capacitor Cs3 is connected to one end of the ignition ball GP3, and the other end of the main capacitor Cs3 is divided into three paths, the first path is connected to the first path of one end of L2, the second path is connected to one end of C3, and the third path is connected to one end of the delay capacitor Cd1; The other end of the ignition ball GP3 is divided into two paths, the first path is connected to one end of the fifth auxiliary switch AB5, and the second path is connected to one end of Ls2; The other end of the fifth auxiliary switch ABS is connected to the other end of L2, the other end of Ls2 is connected to one end of R5, the other end of R5 has two paths, the first path is connected to the first path of one end of R3, and the other end of R3 is connected to the other end of C3; The second path at one end of L2 is connected to the other end of C3, and the other end of the delay capacitor Cd1 is divided into two paths, the first path is connected to the second path at the other end of R5, and the second path is connected to the second path at one end of R3.

10. A T00a test method for a high voltage circuit breaker under high asymmetry conditions, characterized in that: The method is carried out using the test circuit according to any one of claims 1 to 9, comprising: Put the current source, auxiliary switch mechanism and the circuit breaker under test TO in the closed state so that each voltage source is in the charging state; After the current flows for a period of time, the auxiliary switch mechanism and the circuit breaker under test TO are disconnected at the same zero point of the current; Control the ignition ball GP3 to ignite, connect the third voltage source to one end of the circuit breaker TO under test, so that the circuit breaker is in an arcing state, and the third voltage source generates a high-frequency current; The auxiliary switch mechanism is separated when the power frequency current of the second voltage source passes through the first zero point, and the second voltage source is short-circuited. After waiting for a period of time, the auxiliary switch mechanism is closed to restore the power frequency voltage of the tested circuit breaker after it is disconnected.

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