Multi-channel automatic switching test circuit for capacitor charge and discharge test

Abstract

The utility model discloses a multi-channel automatic switching circuit for capacitor charge and discharge test, including a charging circuit, a discharging circuit and an automatic switching control circuit, wherein the charging circuit and the discharging circuit are connected to the capacitor to be tested, and there are multiple capacitors to be tested, and the automatic switching control circuit includes an AC power supply, multiple time relays and multiple AC contactors, and the multiple time relays control the power-on and power-off states of the multiple AC contactors through their contact switches, thereby controlling the charge and discharge states of the multiple capacitors to be tested through the contact switches of the multiple AC contactors. The utility model realizes the automatic control function of charging and discharging start and stop of multiple capacitors to be tested, and can complete the automatic control of the sequential charging and discharging tests of multiple capacitors to be tested in a test operation placed in a constant temperature box at one time, greatly improving the test accuracy and test efficiency, and is easy to operate, saving time and labor costs.

Description

Technical Field

[0001] The utility model relates to a capacitor charging and discharging test circuit, in particular to a multi-channel automatic switching test circuit used for capacitor charging and discharging test. Background Art

[0002] According to the requirements of China's national standard GTBT2693-2001, capacitors need to undergo a high-temperature dynamic withstand voltage test (i.e., charge and discharge test). The capacitor is placed in a constant temperature box, and the lead end is connected to an external charge and discharge device. Then the constant temperature box door is closed and the temperature is raised to the required temperature and kept constant for 10 minutes. Then a DC dynamic voltage is applied for continuous charge and discharge test. Each charge and discharge time is set to A minutes (usually 3 minutes), and the rest time is set to B minutes (usually 10 minutes). A total of C times (usually 3 to 10 times) are performed, and the charge and discharge frequency is about (4 to 10) Hz.

[0003] like Figure 1 As shown, the conventional capacitor charge and discharge test circuit includes a charging circuit and a discharging circuit, wherein the charging circuit includes a dynamic DC power supply V DC , a first resistor R1 and a diode D, the discharge circuit includes a gas discharge tube GDT, a first inductor L1, a second inductor L2, a second resistor R2 and a feedback capacitor C1, the first inductor L1 and the second inductor L2 generally adopt common mode inductors, the positive electrode of the dynamic DC power supply is connected in series with the first resistor R1 and then connected to the positive electrode of the diode D, one end of the gas discharge tube GDT is connected to one end of the first inductor L1 and one end of the second inductor L2, the other end of the first inductor L1 is connected to the positive electrode of the feedback capacitor C1, the other end of the second inductor L2 is connected to one end of the second resistor R2, the cathode of the diode D, the other end of the gas discharge tube GDT and the positive electrode of the capacitor Cx to be measured are connected to each other, the cathode of the feedback capacitor C1, the other end of the second resistor R2, the cathode of the capacitor Cx to be measured and the dynamic DC power supply V DC The negative output terminals are connected to each other.

[0004] During the test, the dynamic DC power supply V DCThe DC voltage is applied to the capacitor Cx under test through the first resistor R1 and the diode D, realizing the charging process of the capacitor Cx under test; at the same time, it can also be applied to the gas discharge tube GDT through the first resistor R1, the diode D, the second inductor L2 and the second resistor R2. During the charging period, the resistance of the gas discharge tube GDT is very large and it is in an open circuit state. Once the applied DC voltage reaches the breakdown voltage of the gas discharge tube GDT, it causes the gas in the tube to ionize, and the gas discharge tube GDT is turned on, which is approximately short-circuited. At this time, the discharge process of the capacitor Cx under test is realized; the time required for the gas discharge tube GDT to be turned on and off is very short (milliseconds). If the breakdown voltage of the gas discharge tube GDT is 2kV, when the charging voltage on the capacitor Cx under test reaches 2kV, the gas discharge tube GDT is turned on instantly, and the voltage on the capacitor Cx under test is discharged through the gas discharge tube GDT, the second inductor L2 and the second resistor R2; at the same time, when the gas discharge tube GDT is turned on, the dynamic DC power supply V D C The DC voltage charges the feedback capacitor C1 through the first resistor R1, the diode D, the gas discharge tube and the first inductor L1. As the voltage on the capacitor Cx under test decreases, the gas discharge tube GDT changes from on to off; while the capacitor Cx under test starts to charge again, the full voltage on the feedback capacitor C1 is discharged through the first inductor L1, the second inductor L2 and the second resistor R2. The charging and discharging process is cyclic and takes a very short time. The general charging and discharging frequency is about (4~10) Hz, and the frequency is determined by the selected first resistor R1 and the capacitor Cx under test.

[0005] The above-mentioned traditional capacitor charge and discharge test circuit is used to perform a charge and discharge test on the capacitor Cx under test, but there are the following defects: the charge and discharge start and stop time of the capacitor Cx under test is timed by a stopwatch and cannot be completed automatically, resulting in low test accuracy and troublesome problems. Moreover, only one capacitor Cx under test can be measured in a test operation placed in a constant temperature box at a time, which is time-consuming, labor-intensive and inefficient. Utility Model Content

[0006] The purpose of the utility model is to provide a multi-channel automatic switching test circuit for capacitor charging and discharging test with high test accuracy, high efficiency and easy operation in order to solve the above problems.

[0007] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0008] A multi-channel automatic switching test circuit for capacitor charging and discharging test, comprising a charging circuit and a discharging circuit, wherein the positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrode of the capacitor under test, and the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the negative electrode of the capacitor under test, and the capacitor under test is multiple, and the multi-channel automatic switching test circuit for capacitor charging and discharging test also includes an automatic switching control circuit, and the automatic switching control circuit includes an AC power supply, multiple time relays and multiple AC contactors, the live wire of the AC power supply, one end of the coil of the first time relay and the common end of the contact switch of the first time relay are connected to each other, the normally closed end of the contact switch of the first time relay is suspended, and the normally open end of the contact switch of the first time relay, one end of the coil of the second time relay and the common end of the contact switch of the second time relay are connected to each other. The common ends of the contact switches are connected to each other, starting from the second time relay, the normally closed end of the contact switch of the previous time relay, one end of the coil of the next time relay and the common end of the contact switch of the next time relay are connected to each other, and the normally closed end of the contact switch of the last time relay is suspended, starting from the normally open end of the contact switch of the second time relay to the normally open end of the contact switch of the last time relay, they are respectively connected to one end of the coils of the multiple corresponding AC contactors, the other ends of the coils of the multiple time relays, the other ends of the coils of the multiple AC contactors and the neutral line of the AC power supply are connected to each other, and the multiple capacitors under test are respectively connected in series with the common ends and normally open ends of the contact switches of the multiple corresponding AC contactors, and then respectively connected to the charging circuit and the discharging circuit, and the normally closed ends of the contact switches of the multiple AC contactors are suspended.

[0009] Preferably, in order to make the circuit more reasonable, the positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrodes of the multiple capacitors under test, the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the normally open ends of the contact switches of the multiple AC contactors, and the negative electrodes of the multiple capacitors under test are respectively connected to the common ends of the contact switches of the multiple AC contactors.

[0010] Preferably, for ease of application, the number of the capacitor to be tested and the number of the AC contactors are four, and the number of the time relays are five.

[0011] Preferably, in order to achieve better charging and discharging effects, the charging circuit includes a dynamic DC power supply, a first resistor and a diode; the discharging circuit includes a gas discharge tube, a first inductor, a second inductor, a second resistor and a feedback capacitor; the positive electrode of the dynamic DC power supply is connected in series with the first resistor and then connected to the positive electrode of the diode; the negative electrode of the diode serves as the positive output end of the charging circuit; the negative electrode of the dynamic DC power supply serves as the negative output end of the charging circuit; one end of the gas discharge tube is connected to one end of the first inductor and one end of the second inductor; the other end of the first inductor is connected to the positive electrode of the feedback capacitor; the other end of the second inductor is connected to one end of the second resistor; the other end of the gas discharge tube serves as the positive input end of the discharge circuit; the negative electrode of the feedback capacitor and the other end of the second resistor are connected to each other and serve as the negative input end of the discharge circuit.

[0012] Preferably, in order to make the structure more compact, the first inductor and the second inductor are common mode inductors.

[0013] The beneficial effects of the utility model are:

[0014] The utility model adds an automatic switching control circuit for controlling the start and stop of charging and discharging of multiple capacitors under test, utilizes the time setting of a time relay and the conversion control of its contact switch, realizes the on-off start and stop and time control of an AC contactor, and finally realizes the automatic control function of the start and stop of charging and discharging of multiple capacitors under test. It can complete the automatic control of the sequential charging and discharging tests of multiple capacitors under test in a test operation placed in a constant temperature box at one time, greatly improves the test accuracy and test efficiency, is easy to operate, and saves time and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the circuit diagram of the traditional capacitor charging and discharging test circuit;

[0016] Figure 2 It is a circuit diagram of the connection between the charging circuit, the discharging circuit and the capacitor to be tested in the multi-channel automatic switching test circuit for capacitor charging and discharging test described in the utility model;

[0017] Figure 3 The utility model discloses a circuit diagram of an automatic switching control circuit in a multi-channel automatic switching test circuit for capacitor charging and discharging test. DETAILED DESCRIPTION

[0018] The utility model is further described below in conjunction with the accompanying drawings:

[0019] like Figure 2 and Figure 3As shown, the multi-channel automatic switching test circuit for capacitor charging and discharging test of the utility model includes a charging circuit (the specific structure is referred to the content described later) and a discharging circuit (the specific structure is referred to the content described later), the positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrode of the capacitor under test, the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the negative electrode of the capacitor under test, and the capacitor under test is multiple (refer to the first capacitor under test Cx1, the second capacitor under test Cx2, the third capacitor under test Cx3, and the fourth capacitor under test Cx4 in the following content), and the multi-channel automatic switching test circuit for capacitor charging and discharging is used for the test of the capacitor. The multi-channel automatic switching test circuit of the electrical test also includes an automatic switching control circuit, which includes an AC power supply, a plurality of time relays (refer to the first time relay KT1, the second time relay KT2, the third time relay KT3, the fourth time relay KT4, and the fifth time relay KT5 in the following content) and a plurality of AC contactors (refer to the first AC contactor J1, the second AC contactor J2, the third AC contactor J3, and the fourth AC contactor J4 in the following content), the live wire L of the AC power supply, one end of the coil of the first time relay (i.e., one end of the power input end) and the first time relay The common ends of the contact switches of the relays are connected to each other, the normally closed end of the contact switch of the first time relay is suspended, the normally open end of the contact switch of the first time relay, one end of the coil of the second time relay and the common end of the contact switch of the second time relay are connected to each other, starting from the second time relay, the normally closed end of the contact switch of the previous time relay, one end of the coil of the next time relay and the common end of the contact switch of the next time relay are connected to each other, the normally closed end of the contact switch of the last time relay is suspended, starting from the normally open end of the contact switch of the second time relay The normally open end of the contact switch of the last time relay is respectively connected to one end of the coil of the multiple AC contactors (i.e., one end of the power input end), the other end of the coil of the multiple time relays (i.e., the other end of the power input end), the other end of the coil of the multiple AC contactors (i.e., the other end of the power input end) and the neutral line N of the AC power supply are connected to each other, and the multiple capacitors under test are respectively connected in series with the common end and the normally open end of the contact switches of the multiple AC contactors, and then respectively connected to the charging circuit and the discharging circuit, and the normally closed ends of the contact switches of the multiple AC contactors are suspended. As needed, the AC power supply can also adopt a DC power supply, then the live wire is changed to the positive pole of the DC power supply, the neutral wire is changed to the negative pole of the DC power supply, and the AC contactor is changed to a relay. The above starting from the second time relay means starting from the second time relay as the first time relay before the first.

[0020] Preferably, in order to make the circuit more reasonable, the positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrodes of the plurality of capacitors under test, the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the normally open terminals of the contact switches of the plurality of AC contactors, and the negative electrodes of the plurality of capacitors under test are respectively connected to the common terminals of the contact switches of the plurality of AC contactors; in order to achieve better charging and discharging effects, the charging circuit includes a dynamic DC power supply V D C , a first resistor R1 and a diode D, the discharge circuit includes a gas discharge tube GDT, a first inductor L1, a second inductor L2, a second resistor R2 and a feedback capacitor C1, a dynamic DC power supply V D C The positive electrode of the first resistor R1 is connected in series and then connected to the positive electrode of the diode D. The negative electrode of the diode D serves as the positive output terminal of the charging circuit. The dynamic DC power supply V DC The negative electrode of the charging circuit serves as the negative output terminal of the charging circuit, one end of the gas discharge tube GDT is connected to one end of the first inductor L1 and one end of the second inductor L2, the other end of the first inductor L1 is connected to the positive electrode of the feedback capacitor C1, the other end of the second inductor L2 is connected to one end of the second resistor R2, the other end of the gas discharge tube GDT serves as the positive input terminal of the discharge circuit, the negative electrode of the feedback capacitor C1 and the other end of the second resistor R2 are connected to each other and serve as the negative input terminal of the discharge circuit; in order to make the structure more compact, the first inductor L1 and the second inductor L2 are common mode inductors.

[0021] For ease of application and to more clearly illustrate the working principle of the utility model, there are four capacitors to be measured, namely, a first capacitor to be measured Cx1, a second capacitor to be measured Cx2, a third capacitor to be measured Cx3 and a fourth capacitor to be measured Cx4, there are four AC contactors, namely, a first AC contactor J1, a second AC contactor J2, a third AC contactor J3 and a fourth AC contactor J4, and there are five time relays, namely, a first time relay KT1, a second time relay KT2, a third time relay KT3, a fourth time relay KT4 and a fifth time relay KT5.

[0022] like Figure 3As shown, the live wire L of the AC power supply, one end of the coil of the first time relay KT1 and the common end of the contact switch KT11 of the first time relay KT1 are connected to each other, the normally closed end of the contact switch KT11 of the first time relay KT1 is suspended, the normally open end of the contact switch KT11 of the first time relay KT1, one end of the coil of the second time relay KT2 and the common end of the contact switch KT21 of the second time relay KT2 are connected to each other, the normally closed end of the contact switch KT21 of the second time relay KT2, one end of the coil of the third time relay KT3 and the common end of the contact switch KT21 of the third time relay KT3 are connected to each other, and the normally closed end of the contact switch KT21 of the second time relay KT2, one end of the coil of the third time relay KT3 and the common end of the contact switch KT21 of the third time relay KT3 are connected to each other. The common end of the contact switch K31 of T3 is connected to each other, the normally closed end of the contact switch KT31 of the third time relay KT3, one end of the coil of the fourth time relay KT4 and the common end of the contact switch K41 of the fourth time relay KT4 are connected to each other, the normally closed end of the contact switch KT41 of the fourth time relay KT4, one end of the coil of the fifth time relay KT5 and the common end of the contact switch KT51 of the fifth time relay KT5 are connected to each other, the normally closed end of the contact switch KT51 of the fifth time relay KT5 is suspended, and the contact switch KT2 of the second time relay KT2 is suspended. The normally open end of the contact switch KT1 of the fifth time relay KT5 is connected to one end of the coil of the fourth AC contactor J4, and the other end of the coil of the first time relay KT1, the other end of the coil of the second time relay KT2, the other end of the coil of the third time relay KT3, and the other end of the coil of the third time relay KT3 are connected. The other end of the coil of the fourth time relay KT4, the other end of the coil of the fifth time relay KT5, the other end of the coil of the first AC contactor J1, the other end of the coil of the second AC contactor J2, the other end of the coil of the third AC contactor J3, the other end of the coil of the fourth AC contactor J4 and the neutral line N of the AC power supply are connected to each other, the cathode of the diode D, the other end of the gas discharge tube GDT, the anode of the first measured capacitor Cx1, the anode of the second measured capacitor Cx2, the anode of the third measured capacitor Cx3 and the anode of the fourth measured capacitor Cx4 are connected, and the dynamic DC power supply V DCThe negative electrode of the feedback capacitor C1, the other end of the second resistor R2, the normally open end of the contact switch J11 of the first AC contactor J1, the normally open end of the contact switch J21 of the second AC contactor J2, the normally open end of the contact switch J31 of the third AC contactor J3 and the normally open end of the contact switch J41 of the fourth AC contactor J4 are connected, the positive electrode of the first measured capacitor Cx1 is connected to the common end of the contact switch J11 of the first AC contactor J1, the positive electrode of the second measured capacitor Cx2 is connected to the common end of the contact switch J21 of the second AC contactor J2, the positive electrode of the third measured capacitor Cx3 is connected to the common end of the contact switch J31 of the third AC contactor J3, and the positive electrode of the fourth measured capacitor Cx4 is connected to the common end of the contact switch J41 of the fourth AC contactor J4.

[0023] like Figure 2 and Figure 3 As shown, taking the test of "charging and discharging for 3 minutes, stopping for 9 minutes, and doing 5 times in total" for a tested capacitor as an example, the test processes of the first tested capacitor Cx1, the second tested capacitor Cx2, the third tested capacitor Cx3 and the fourth tested capacitor Cx4 of the utility model are described in detail in sequence.

[0024] First, set the working time of the second time relay KT2, the third time relay KT3, the fourth time relay KT4 and the fifth time relay KT5 to 3 minutes, the stop time of the second time relay KT2 to 9 minutes, the stop time of the third time relay KT3 to 6 minutes, the stop time of the fourth time relay KT4 to 3 minutes, and the stop time of the fifth time relay KT5 to 0 minutes. Because the charging and discharging takes 3 minutes, the time required for the four capacitors is 12 minutes, that is, it takes 12 minutes to complete a cycle, and the time required to complete 5 cycles is 60 minutes. Therefore, the working time of the first time relay KT1 is set to 60 minutes, and the stop time of the first time relay KT1 is set longer, so that the test personnel can stop the test after 60 minutes, because each capacitor has undergone 5 3-minute charging and discharging tests within 60 minutes.

[0025] Before starting the test or after completing the test, the first time relay KT1 is in the disconnected state, the normally open end of the contact switch KT11 of the first time relay KT1 is disconnected, the second time relay KT2, the third time relay KT3, the fourth time relay KT4, the fifth time relay KT2, the first AC contactor J1, the second AC contactor J2, the third AC contactor J3, the fourth AC contactor J4, the first measured capacitor Cx1, the second measured capacitor Cx2, the third measured capacitor Cx3 and the fourth measured capacitor Cx4 are all in the disconnected state.

[0026] After the test starts, AC power is loaded at both ends of the coil of the first time relay KT1, the first time relay KT1 is in the on state (this state will be maintained for 60 minutes), the normally open end of the contact switch KT11 of the first time relay KT1 is closed and the normally closed end is disconnected, the second time relay KT2 is energized and in the on state, the normally open end of the contact switch KT21 of the second time relay KT2 is closed and the normally closed end is disconnected, the third time relay KT3, the fourth time relay KT4, the fifth time relay KT2, the second AC contactor J2, the third AC contactor J3, the fourth AC contactor J4, the second measured capacitor Cx2, the third measured capacitor Cx3 and the fourth measured capacitor Cx4 are all in the disconnected state, the first AC contactor J1 is energized and in the on state, the normally open end of the contact switch J11 of the first AC contactor J1 is closed and the normally closed end is disconnected, the dynamic DC power supply V D C The DC voltage is loaded on both ends of the first measured capacitor Cx1 through the first resistor R1 and the diode D, and the first measured capacitor Cx1 begins to be charged; after the first measured capacitor Cx1 is charged for nearly 3 minutes, the gas discharge tube GDT is turned on, and the voltage on the first measured capacitor Cx1 is immediately discharged quickly through the gas discharge tube GDT, the second inductor L2 and the second resistor R2 to complete the discharge; exactly 3 minutes later, the first measured capacitor Cx1 completes a charge and discharge test process, and at the same time, the second time relay KT2 loses power and is in a disconnected state (this state will last for 9 minutes), the normally open end of the contact switch KT21 of the second time relay KT2 is disconnected and the normally closed end is closed, and the third time relay KT3 is energized and is in a conducting state The normally open end of the contact switch KT31 of the third time relay KT3 is closed and the normally closed end is disconnected, the first AC contactor J1 is de-energized and in the disconnected state, the normally open end of the contact switch J11 of the first AC contactor J1 is disconnected and the normally closed end is closed, and the first measured capacitor Cx1 is disconnected from the power supply; at the same time, the control process of the second time relay KT2 is the same as that of the third time relay KT3, the third time relay KT3 is energized and in the on state, and the second measured capacitor Cx2 begins to be charged for nearly 3 minutes, and then immediately discharged, and the second measured capacitor Cx2 completes a charge and discharge test process, so that the purpose of the third measured capacitor Cx3 completing a charge and discharge test process and the fourth measured capacitor Cx4 completing a charge and discharge test process is achieved in sequence.

[0027] After the fourth measured capacitor Cx4 completes a charge and discharge test process, 12 minutes are used up, the first round of charge and discharge test is completed, the first time relay KT1 continues to be in the on state, the second time relay KT2 is energized for the second time and is in the on state, and the second round of charge and discharge test process begins, and the first measured capacitor Cx1, the second measured capacitor Cx2, the third measured capacitor Cx3, and the fourth measured capacitor Cx4 are charged and discharged in turn; then 24 minutes are used up, the third round of charge and discharge test process begins, and then the fourth round of charge and discharge test process and the fifth round of charge and discharge test process begin, and 60 minutes are used up, the first time relay KT1 loses power and is in the disconnected state, completing the process of 5 rounds of 3min charge and discharge tests for each capacitor, and all components return to their initial states.

[0028] The above embodiments are only preferred embodiments of the present utility model and are not limitations on the technical solutions of the present utility model. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present utility model.

Claims

1. A multi-channel automatic switching test circuit for capacitor charge and discharge test, comprising a charging circuit and a discharging circuit, wherein the positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrode of the capacitor under test, and the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the negative electrode of the capacitor under test, characterized in that: There are multiple capacitors to be tested, and the multi-channel automatic switching test circuit for capacitor charging and discharging test also includes an automatic switching control circuit. The automatic switching control circuit includes an AC power supply, multiple time relays and multiple AC contactors. The live wire of the AC power supply, one end of the coil of the first time relay and the common end of the contact switch of the first time relay are connected to each other, the normally closed end of the contact switch of the first time relay is suspended, the normally open end of the contact switch of the first time relay, one end of the coil of the second time relay and the common end of the contact switch of the second time relay are connected to each other, starting from the second time relay, the normally closed end of the contact switch of the previous time relay, the normally open end of the contact switch of the next time relay, and the normally closed end of the contact switch of the previous time relay are suspended. One end of the coil of the device is connected to the common end of the contact switch of the next time relay, and the normally closed end of the contact switch of the last time relay is suspended. From the normally open end of the contact switch of the second time relay to the normally open end of the contact switch of the last time relay, they are respectively connected to one end of the coils of the multiple corresponding AC contactors, the other ends of the coils of the multiple time relays, the other ends of the coils of the multiple AC contactors and the neutral line of the AC power supply are connected to each other, and the multiple capacitors under test are respectively connected in series with the common end and the normally open end of the contact switches of the multiple corresponding AC contactors, and then respectively connected to the charging circuit and the discharging circuit, and the normally closed ends of the contact switches of the multiple AC contactors are suspended.

2. The multi-channel automatic switching test circuit for capacitor charge and discharge test according to claim 1, characterized in that: The positive output terminal of the charging circuit and the positive input terminal of the discharging circuit are both connected to the positive electrodes of the multiple capacitors under test, the negative output terminal of the charging circuit and the negative input terminal of the discharging circuit are both connected to the normally open ends of the contact switches of the multiple AC contactors, and the negative electrodes of the multiple capacitors under test are respectively connected to the common ends of the contact switches of the multiple AC contactors.

3. The multi-channel automatic switching test circuit for capacitor charge and discharge test according to claim 1 or 2, characterized in that: The number of the capacitors to be tested and the number of the AC contactors are both four, and the number of the time relays is five.

4. The multi-channel automatic switching test circuit for capacitor charge and discharge test according to claim 1 or 2, characterized in that: The charging circuit includes a dynamic DC power supply, a first resistor and a diode; the discharging circuit includes a gas discharge tube, a first inductor, a second inductor, a second resistor and a feedback capacitor; the positive electrode of the dynamic DC power supply is connected in series with the first resistor and then connected to the positive electrode of the diode; the negative electrode of the diode serves as the positive output end of the charging circuit; the negative electrode of the dynamic DC power supply serves as the negative output end of the charging circuit; one end of the gas discharge tube is connected to one end of the first inductor and one end of the second inductor; the other end of the first inductor is connected to the positive electrode of the feedback capacitor; the other end of the second inductor is connected to one end of the second resistor; the other end of the gas discharge tube serves as the positive input end of the discharge circuit; the negative electrode of the feedback capacitor and the other end of the second resistor are connected to each other and serve as the negative input end of the discharge circuit.

5. The multi-channel automatic switching test circuit for capacitor charge and discharge test according to claim 4, characterized in that: The first inductor and the second inductor are common mode inductors.

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