CN-121995183-A - Test circuit and test method for measuring withstand voltage characteristics of vacuum switch after arc

Abstract

The technical field of circuit withstand voltage test, in particular to a test circuit and a test method for measuring withstand voltage characteristics of a vacuum switch after arc. The current generating branch is connected to the first end of the vacuum switch to generate arcing current flowing through the vacuum switch to be tested, the current converting branch is connected in parallel to the two ends of the vacuum switch to be tested, the second end of the vacuum switch to be tested is connected to a common connection point, the current converting branch is put into after the vacuum switch to be tested is disconnected to realize current reversing and establish transient recovery voltage at the two ends, one end of the oscillation energy absorbing branch is connected to the first end of the vacuum switch to be tested, and the other end of the oscillation energy absorbing branch is connected to the common connection point. The technical scheme can construct a concise topology, naturally generate high-speed rising transient recovery voltage by utilizing the reverse charging characteristic of the small-capacity converter capacitor after the zero crossing of current, realize the breakdown test of the vacuum switch after the arc without an additional heavy voltage circuit, and further control the arcing and the converter action through time sequence so as to accurately adjust the arcing time.

Inventors

• LIU JIALONG
• SU JIALIANG
• GUO ZEYANG
• ZHU TAO
• LI JIANGJUN
• CHEN HONGGE
• LIN BAOXIN
• XU JIELONG
• WU MEI
• PANG ZHENYANG
• HAN JIAJUN
• Li Duiqing
• WU QINGQIN
• ZHOU XIANDA
• CHEN XIAOSHU
• CHEN ZHANGMAO
• TIAN CHUN
• WU ZHIPENG
• LI TIANCHU
• CHEN LINCONG
• LIANG YU
• LIN DAOHONG
• LI JUNWEN
• FU HONGFU

Assignees

• 海南电网有限责任公司儋州供电局

Dates

Publication Date

20260508

Application Date

20260312

Claims (9)

1. 1. A test circuit for measuring withstand voltage characteristics of a vacuum switch after an arc is characterized by comprising, The current generation branch circuit (1) is connected to the first end of the vacuum switch (4) to be tested and generates arcing current flowing through the vacuum switch to be tested; The current conversion branch circuit (2) is connected in parallel with two ends of the vacuum switch (4) to be tested, the second end of the vacuum switch (4) to be tested is connected to the public connection point, the current conversion branch circuit (2) is put into after the vacuum switch (4) to be tested is switched off, current conversion is realized, and transient recovery voltages are established at the two ends; And one end of the oscillation energy absorption branch (3) is connected to the first end of the vacuum switch (4) to be tested, and the other end of the oscillation energy absorption branch is connected to the public connection point.
2. 2. The test circuit for measuring withstand voltage characteristics after an arc of a vacuum switch according to claim 1, wherein: A first LC oscillating unit (11) and a first charging unit (12) are arranged in the current generating branch (1); A first LC oscillating unit (11) comprising a first capacitor (111) and a first inductor (112) connected in series; a first charging unit (12) including a first charging power source (121), a first charging switch (122) and a first charging resistor (123); the positive electrode of the first charging power supply (121) is connected to the high potential end of the first capacitor (111) through a first charging switch (122) and a first charging resistor (123) which are sequentially connected in series, and the negative electrode is connected to the low potential end of the first capacitor (111); The first LC oscillating unit (11) is connected to the main current path via a first control switch (5).
3. 3. The test circuit for measuring withstand voltage characteristics after an arc of a vacuum switch according to claim 1, wherein: a second LC oscillating unit (21) and a second charging unit (22) are arranged in the commutation branch (2); A second LC oscillating unit (21) comprising a second capacitor (211) and a second inductor (212) connected in series; a second charging unit (22) including a second charging power source (221), a second charging switch (222) and a second charging resistor (223); The anode of the second charging power supply (221) is connected to the high potential end of the second capacitor (211) through a second charging switch (222) and a second charging resistor (223) which are sequentially connected in series, and the cathode is connected to the low potential end of the second capacitor (211); the second LC oscillating unit (21) is connected to the main current path via a second control switch (6).
4. 4. The test circuit for measuring withstand voltage characteristics after an arc of a vacuum switch according to any one of claims 1 to 3, wherein: A first discharge unit (13) and a second discharge unit (23) are respectively arranged in the current generation branch (1) and the current conversion branch (2); The first discharge unit (13) and the second discharge unit (23) comprise a discharge switch and a discharge resistor.
5. 5. The test circuit for measuring withstand voltage characteristics after an arc of a vacuum switch as recited in claim 4, wherein: The oscillation energy absorption branch circuit (3) comprises a third control switch (31) and an energy absorption lightning arrester (32) which are connected in series; the capacitance value of the second capacitor (211) is smaller than the capacitance value of the first capacitor (111).
6. 6. A testing method comprises the testing circuit for measuring the withstand voltage characteristics of a vacuum switch after an arc, and is characterized by further comprising the following steps: When the current generation branch circuit (1) provides oscillation current for the closed vacuum switch (4) to be tested, the vacuum switch (4) to be tested is controlled to be opened to start arcing; After the arcing of the vacuum switch (4) to be tested lasts for a set time, the vacuum switch is put into the converter branch (2), and current is converted from the current generating branch (1) to the converter branch (2), so that the two ends of the vacuum switch (4) to be tested bear transient recovery voltage; After the tested vacuum switch (4) breaks down due to transient recovery voltage, residual energy in the loop is absorbed through the oscillation energy absorption branch (3).
7. 7. The test method of claim 6, wherein: In the charging step before the converter branch (2) is put into operation, Closing a first charging switch (122) in the current generation branch (1), and charging the first capacitor (111) to a first preset voltage through a first charging power supply (121) and a first charging resistor (123); Closing a second charging switch (222) in the commutation branch, and charging a second capacitor (211) to a second preset voltage through a second charging power supply (211) and a second charging resistor (223); after the charging is completed, the first charging switch (122) and the second charging switch (222) are turned off.
8. 8. The test method according to claim 7, wherein: In the step of adjusting the parameters, Adjusting the power supply voltage for charging the second capacitor (211), selecting inductance parameters of the converter branch (2), and controlling the current drop rate before zero crossing and the back pressure characteristic born by the tested vacuum switch (4) after arc; the voltage value of the second charging power supply (221) is adjusted, the second inductor (212) with different inductance values is replaced, and the current change rate in the current conversion process is changed.
9. 9. The test method according to claim 8, wherein: in the step of controlling the arcing time, The vacuum switch (4) to be tested is controlled to be opened before the oscillation current provided by the current generation branch circuit (1) reaches the peak value; The second control switch (6) is kept to be closed at a set fixed time, and the arcing time adjustment is realized by only changing the opening time of the tested vacuum switch (4).

Description

Test circuit and test method for measuring withstand voltage characteristics of vacuum switch after arc Technical Field The invention relates to the technical field of circuit withstand voltage test, in particular to a test circuit and a test method for measuring withstand voltage characteristics of a vacuum switch after an arc. Background At present, the test method for the withstand voltage characteristic of the vacuum switch after arc is mostly based on a power frequency or low-frequency oscillation loop, and is difficult to truly simulate the transient stress environment with high frequency and high di/dt in the actual breaking process of the direct current breaker. The existing high-frequency oscillation test circuit is complex in structure, and needs multistage voltage superposition or additional high-voltage application loops after arc, so that the system is high in cost, high in control difficulty and inflexible in parameter adjustment. The existing method has limited capability in the aspect of simulating the test working conditions of the synergistic influence of multiple parameters such as different arcing time, different current drop rates, different back pressure after arcing and the like, and is difficult to systematically study the influence rule of each factor on the recovery of the medium after the arcing of the vacuum switch, so that the accurate type selection and the performance optimization of the vacuum switch in the direct current switching application are restricted. Therefore, a simple topology can be constructed, the transient recovery voltage rising at high speed is naturally generated by utilizing the reverse charging characteristic of the small-capacity converter capacitor after the zero crossing of the current, the post-arc breakdown test of the vacuum switch is realized without an additional heavy voltage circuit, and the test circuit and the test method for measuring the post-arc withstand voltage characteristic of the vacuum switch, which can accurately adjust the arcing time, can also meet the current environmental requirements by controlling the arcing and the converter action in time sequence. Disclosure of Invention Therefore, the technical problem to be solved by the invention is that the existing high-frequency oscillation test circuit is complex in structure, and needs multistage voltage superposition or additional high-voltage application loop after arc, so that the system cost is high, the control difficulty is high, the parameter adjustment is inflexible, and the capability of the existing method in simulating test working conditions of the synergistic effect of multiple parameters such as different arcing time, different current reduction rate, different back pressure after arc and the like is limited. The technical problems are solved by the following technical proposal that the invention provides a test circuit for measuring the withstand voltage characteristic of a vacuum switch after arc, which comprises, The current generation branch is connected to the first end of the vacuum switch to be tested and generates arcing current flowing through the vacuum switch to be tested; The current conversion branch is connected in parallel with two ends of the vacuum switch to be tested, the second end of the vacuum switch to be tested is connected to the common connection point, the current conversion branch is put into after the vacuum switch to be tested is switched off, current conversion is realized, and transient recovery voltages are established at the two ends; and one end of the oscillation energy absorption branch is connected to the first end of the vacuum switch to be tested, and the other end of the oscillation energy absorption branch is connected to the public connection point. In a preferred embodiment of the test circuit for measuring the withstand voltage characteristics after an arc of a vacuum switch according to the present invention: a first LC oscillating unit and a first charging unit are arranged in the current generation branch; the first LC oscillating unit comprises a first capacitor and a first inductor which are connected in series; The first charging unit comprises a first charging power supply, a first charging switch and a first charging resistor; The positive electrode of the first charging power supply is connected to the high potential end of the first capacitor through a first charging switch and a first charging resistor which are sequentially connected in series, and the negative electrode of the first charging power supply is connected to the low potential end of the first capacitor; the first LC oscillating unit is connected to the main current path through a first control switch. In a preferred embodiment of the test circuit for measuring the withstand voltage characteristics after an arc of a vacuum switch according to the present invention: a second LC oscillating unit and a second charging unit are arranged in the commutation br