A closing resistor lightning impulse withstand test device and test method for circuit breakers

Abstract

This invention discloses a lightning impulse withstand test device and method for circuit breaker closing resistors. The test device includes a controllable high-voltage DC charging power supply, a lightning impulse discharge unit, and a computer-controlled measurement and management system. The controllable high-voltage DC charging power supply charges the energy storage capacitor of the lightning impulse discharge circuit. The lightning impulse discharge unit generates a lightning impulse voltage and applies it across the closing resistor load. The lightning impulse voltage applied across the pulse load is extracted and recorded by a pulse resistance voltage divider and an oscilloscope, respectively. Through data communication between the computer and the oscilloscope, the control and data processing of the lightning impulse withstand voltage test of the closing resistor are realized. This invention solves the problem that existing lightning impulse voltage test systems cannot perform pulse withstand voltage tests on resistive loads, providing a standardized test technology for the operational safety of circuit breakers and power systems.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering technology, to ultra-high voltage equipment, and in particular to a lightning impulse withstand test device and test method for the closing resistor of a circuit breaker. Background Technology

[0002] With the development of ultra-high voltage power transmission technology in my country, closing resistors are widely used in 330kV and above transmission lines to limit overvoltages generated during the opening and closing of high voltage circuit breakers and suppress arc reignition. They are the core protection for the development of ultra-high voltage and extra-high voltage power transmission and transformation equipment.

[0003] Carbon-ceramic linear resistors represent the most successful research area for circuit breaker closing resistors. However, their formulation, processes, and manufacturing technologies are currently subject to foreign blockade and monopoly, meaning that my country's high-voltage transmission lines rely entirely on imports for their closing resistors. While research on the preparation of carbon-ceramic linear resistors has begun in my country, no substantial technological breakthroughs have been achieved, and high-voltage testing technology remains a blank in the domestic market.

[0004] Lightning impulse withstand voltage testing is a crucial test item for the closing resistance of circuit breakers. In high-voltage insulation testing, MARX lightning impulse generators are widely used for insulation performance testing of electrical insulation materials and power equipment (such as insulators and bushings). However, existing high-voltage testing technologies using MARX lightning impulse generators are primarily designed for high-resistance test objects such as electrical insulation materials and power equipment. They are not suitable for lightning impulse withstand voltage testing of closing resistance and similar power equipment or devices, mainly because the closing resistance of circuit breakers is normally low-resistance. Test results demonstrate that when existing MARX lightning impulse generators are applied to the closing resistance, the impulse voltage waveform applied to the load of the closing resistance will undergo significant distortion. Therefore, research on high-voltage lightning impulse testing technology for circuit breaker closing resistance and the development of testing devices can promote research on the formulation and process of carbon-ceramic linear closing resistors, accelerate their application in ultra-high voltage transmission systems, and establish test standards for circuit breaker closing resistance, all of which have significant theoretical and engineering application value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a lightning impulse withstand test device and method for circuit breaker closing resistors, and to establish a test device and method suitable for lightning impulse withstand voltages with different resistance values.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A lightning impulse withstand test device for a closing resistor of a circuit breaker includes a controllable high-voltage DC charging power supply, a lightning impulse discharge unit, a closing resistor load, and a computer measurement and control management system.

[0008] The controllable high-voltage DC charging power supply consists of an adjustable high-voltage DC charging power supply and a DC voltage divider. The controllable high-voltage DC charging power supply is used to charge the energy storage capacitor element of the lightning impulse discharge unit.

[0009] The lightning impulse discharge unit includes an energy storage capacitor. C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po and closing resistor Z r; closing resistor Z r is the closing resistor load, and the energy storage capacitor is the energy storage capacitor. C 1. Inductance is formed by the discharge switch G and the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po closing resistor Z The r-discharge generates a lightning impulse voltage and applies it across the closing resistor load, producing a lightning impulse voltage waveform that meets the standard requirements;

[0010] The computer-based measurement and control management system is used to automatically monitor the charging process of the closing resistor lightning impulse test, automatically control the process of the closing resistor lightning impulse withstand test, analyze and judge the results of the closing resistor lightning impulse withstand test, and extract, record, store, query and output test reports of the closing resistor impulse withstand voltage test signal.

[0011] Furthermore, the energy storage capacitor C 1. Both ends are connected in parallel with the high-voltage and low-voltage ends of the controllable high-voltage DC charging power supply, and the energy storage capacitor... C The high-voltage terminal of circuit 1 is electrically connected to the high-voltage terminal of discharge switch G, and the low-voltage terminal of discharge switch G forms an inductance with the waveform. L The high-voltage electrical connection forms an inductance waveform. L The low-voltage end forms or protects the resistor with the first waveform. R The electrical connection of the high-voltage end of the PS, the first waveform forming or protection resistor. R The other end of ps is connected to the closing resistor. Z One end of r is electrically connected; load Z The other end of r is connected to the low-voltage end of the controllable high-voltage DC charging power supply or the energy storage capacitor. C 1. Low-voltage electrical connection, second waveform forming or protection resistor. R po is connected in parallel to the discharge switch G, forming an inductance with the waveform. L Electrical connections and energy storage capacitors C Between the low-voltage ends of 1.

[0012] Furthermore, the energy storage capacitor C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po are all components with discretely adjustable parameters.

[0013] Furthermore, the computer-controlled measurement and management system includes a pulse voltage divider, an oscilloscope, a control unit, and a computer; the control unit consists of a charging voltage monitoring circuit and a programmable controller to realize the process of automatically controlling the lightning impulse withstand test of the closing resistor; the lightning impulse voltage applied across the load terminals of the closing resistor is extracted and recorded by the pulse voltage divider and the oscilloscope, and the control and data processing of the lightning impulse withstand voltage test of the closing resistor are realized through data communication between the computer and the oscilloscope.

[0014] Furthermore, the computer and control unit communicate via optical fiber, and the computer and oscilloscope transmit data via Ethernet port.

[0015] Furthermore, the controllable high-voltage DC charging power supply has a human-machine interface, and its output voltage can be set through its own human-machine interface or regulated by a computer measurement and control management system.

[0016] Furthermore, the current expression in the lightning impulse discharge unit is as follows:

[0017] (7)

[0018] Then it acts on the closing resistor Z The voltage expression across r is:

[0019] (8)

[0020] Acting on the closing resistor Z The rise time of the impulse voltage waveform at both ends r T 1 and half peak time T 2 are respectively 1.67× ( t 90% - t 30% The time interval between the origin of the impulse voltage and the moment when the voltage drops to 50% of its peak value;

[0021] In the formula, The total resistance of the equivalent circuit. The total capacitance of the equivalent circuit. This refers to the charging / discharging voltage across the energy storage capacitor in the lightning impulse discharge unit. t 90% and t30% These represent the times corresponding to the 90% peak value and the 30% peak value of the output voltage wave of the lightning impulse discharge unit, respectively.

[0022] The method for lightning impulse withstand testing of closing resistors for circuit breakers includes the following steps:

[0023] (1) Based on the tested closing resistance Z Select a suitable test circuit based on the resistance value of r; set the lightning impulse voltage test mode, including the polarity of the impulse pulse and the number of impulses; and determine the appropriate test circuit based on the closing resistor. Z The withstand voltage amplitude of r is automatically converted into the discharge voltage of the lightning impulse discharge circuit based on the output efficiency of the lightning impulse discharge unit.

[0024] (2) Start closing resistor Z The lightning impulse withstand test software and computer-controlled measurement and management system automatically control the energy storage capacitor of the lightning impulse discharge unit using a controllable high-voltage DC charging power supply. C The charging process of 1 can be automatically tracked by the energy storage capacitor. C 1. Real-time status of the charging voltage at both ends, when the energy storage capacitor... C When the charging voltage at both ends reaches the preset test conditions, a control pulse is automatically sent to the discharge switch G of the lightning impulse discharge unit to break down and conduct.

[0025] (3) Energy storage capacitor C The electrical energy of 1 passes through the discharge switch G and forms an inductor with the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po discharges to the closing resistor Zr and applies the lightning impulse voltage to the closing resistor. Z The lightning impulse voltage waveform applied across the closing resistor Zr is extracted and recorded by a pulse voltage divider and an oscilloscope, and processed and analyzed through data transmission between the computer and the oscilloscope.

[0026] (4) When the lightning impulse voltage applied across the closing resistor Zr is distorted, the computer measurement and control management system automatically provides the closing resistor value. Z criterion for surface flashover discharge, closing resistance Z The impulse voltage withstand test of r is stopped, and the closing resistance is recorded. Z The maximum impulse voltage value that does not cause flashover is its lightning impulse voltage withstand value.

[0027] (5) Based on the designed discharge circuit form, conduct a theoretical analysis of the correlation between the transient voltage waveform across the closing resistor load and the circuit parameters.

[0028] Furthermore, from the lightning withstand voltage U LI The test begins at 50% of the voltage level. If the test passes, the voltage is then increased in increments of 10% until the closing resistor is reached. Z The maximum voltage that the closing resistor can withstand until a surface flashover occurs is taken as its maximum lightning impulse withstand voltage value.

[0029] Furthermore, in the lightning impulse withstand voltage test of the closing resistor, the closing resistor... Z The circuit is placed in an SF6, N2, or oil-filled environment, and is equipped with protective measures to prevent surface flashover or explosive open circuit of the closing resistor load in the lightning impulse voltage generation circuit.

[0030] This invention relates to a lightning impulse withstand test device for circuit breaker closing resistors, comprising a controllable high-voltage DC charging power supply, a lightning impulse discharge unit, and a computer-based measurement and control management system. The controllable high-voltage DC charging power supply charges the energy storage capacitor in the lightning impulse discharge circuit. The lightning impulse discharge unit generates a lightning impulse voltage and applies it across the closing resistor load. The lightning impulse voltage applied across the load is extracted and recorded by a pulse voltage divider and an oscilloscope, respectively. Data communication between the computer and the oscilloscope enables control and data processing of the lightning impulse withstand voltage test of the closing resistor. This invention solves the problem that existing lightning impulse voltage test systems cannot perform pulse withstand voltage tests on resistive loads, providing a standardized testing technique for the operational safety of circuit breakers and power systems. It can be used in similar scenarios such as lightning impulse withstand voltage testing of resistive loads in the power and communication fields.

[0031] This invention proposes the composition structure of a lightning impulse withstand test device for circuit breaker closing resistors. Based on the designed discharge circuit configuration, a theoretical analysis is conducted on the correlation between the transient voltage waveform across the load terminals of the closing resistor and the circuit parameters, thereby obtaining the circuit parameter design principles for lightning impulse withstand tests of closing resistors with different resistance values.

[0032] This invention allows for the adjustment of appropriate energy storage capacitors, waveform forming inductors, and resistors based on the resistance value of the closing resistor. This ensures that the impulse voltage waveform parameters applied across the load with different resistance values ​​meet the allowable deviation requirements for lightning impulse voltage waveform parameters. The discreet adjustment of components—energy storage capacitors, discharge switches, waveform forming inductors, and resistors—achieves the desired waveform for lightning impulse voltage tests with closing resistors of varying resistance values. Applicable loads can include not only typical closing resistor values, such as 5 ohms or 6 ohms, but also proportional closing resistor units consisting of several resistors connected in series. Attached Figure Description

[0033] Figure 1This is a structural block diagram of a test device for lightning impulse withstand voltage of a closing resistor for a circuit breaker according to the present invention.

[0034] Figure 2a This is a structural diagram of the lightning impulse discharge unit in this invention;

[0035] Figure 2b This is the equivalent circuit of the lightning impulse discharge unit in this invention;

[0036] Figure 3 This is a schematic diagram showing the parameter values ​​of each component in the lightning impulse discharge unit during the lightning impulse withstand voltage test of the closing resistor for a circuit breaker according to the present invention.

[0037] Figure 4 This is a flowchart of the computer measurement and control management system for lightning impulse withstand voltage test of closing resistor for circuit breaker according to the present invention.

[0038] Figure 5 The voltage distortion waveform across the closing resistor during the lightning impulse withstand test of this invention;

[0039] In the diagram: 1-Controllable high-voltage DC charging power supply, 1-1-High-voltage DC charging power supply, 1-2-DC voltage divider, 2-Lightning impulse discharge unit, 3-Closing resistor load, 4-Computer measurement and control management system, 5-Pulse voltage divider, 6-Oscilloscope, 7-Control unit, 8-Computer, 7-1-Charging voltage monitoring circuit, 7-2-Programmable controller. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0041] See Figure 1 The test device for lightning impulse withstand voltage of the closing resistor of the circuit breaker of the present invention consists of a controllable high-voltage DC charging power supply 1, a lightning impulse discharge unit 2, a closing resistor load 3, and a computer measurement and control management system 4. The controllable high-voltage DC charging power supply 1 mainly consists of an adjustable high-voltage DC charging power supply 1-1 and a DC voltage divider 1-2. Its function is to charge the energy storage capacitor element of the lightning impulse discharge unit 2. Its output voltage can be set on its own human-machine interface or controlled by the computer measurement and control management system 4.

[0042] See Figure 2a and Figure 2b The lightning impulse discharge unit 2 mainly includes an energy storage capacitor. C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor Rpo and closing resistor Z The r-component is characterized by its energy storage capacitor. C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R All components po are discretely adjustable to meet the waveform requirements of lightning impulse withstand tests with different closing resistors Zr. The function of lightning impulse discharge unit 2 is to store the charged energy storage capacitor. C 1. Inductance is formed by the discharge switch G and the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R The discharge of po to the closing resistor load 3 generates a lightning impulse voltage, which is applied across the closing resistor load 3, producing a lightning impulse voltage waveform that meets the standard requirements.

[0043] like Figure 1 As shown, the computer-controlled measurement and control management system 4 mainly consists of a pulse voltage divider 5, an oscilloscope 6, a control unit 7, and a computer 8. The control unit 7 mainly consists of a charging voltage monitoring circuit 7-1 and a programmable controller 7-2. The main functions of the computer-controlled measurement and control management system 4 include: ① automatically monitoring the charging process of the closing resistor lightning impulse test; ② cooperating with the computer 8 to automatically control the process of the closing resistor lightning impulse withstand test; ③ realizing the analysis and judgment of the closing resistor lightning impulse withstand test results; ④ extracting, recording, storing, querying, and outputting test reports of the closing resistor impulse withstand voltage test signals.

[0044] The measurement and control management of the closing resistor impulse withstand voltage test is handled by a computer-based measurement and control management system 4, which manages the test process, analyzes, processes, and manages the test data and waveforms. Through pulse voltage divider 5 extraction, oscilloscope 6 acquisition, and computer management software analysis, the closing resistor impulse withstand voltage test can be controlled. Z The system controls the lightning impulse voltage test process and provides test criteria and the maximum lightning impulse withstand voltage value that the closing resistor can withstand. The lightning impulse voltage applied across the load 3 of the closing resistor is extracted and recorded by the pulse voltage divider 5 and oscilloscope 6. Data communication between the computer 8 and the oscilloscope 6 enables the control and data processing of the lightning impulse withstand voltage test of the closing resistor. Therefore, it can be concluded that the circuit breaker closing resistor lightning impulse voltage withstand test device includes multiple functions such as high-voltage charging, discharging, measurement, and management, and can perform type tests and sampling tests on the closing resistor for lightning impulse withstand voltage.

[0045] See Figure 2a , Figure 2bThis invention relates to a lightning impulse withstand test for a closing resistor used in a circuit breaker. The lightning impulse discharge unit 2 mainly consists of an energy storage capacitor. C 1. Waveform forming inductance L and the first waveform to form or protect the resistor R ps, second waveform forming or protection resistor R The po component, through analysis of the transient process of the generating circuit, obtains the value applied to the closing resistor. Z The relationship between the waveform parameters of the impulse voltage across r and the resistance value of the closing resistor Zr and the circuit parameters.

[0046] (a) Electrical connections of the generating circuit:

[0047] Energy storage capacitor of lightning impulse discharge unit 2 C 1 is connected in parallel with the high-voltage and low-voltage terminals of the controllable high-voltage DC charging power supply 1; energy storage capacitor C The high-voltage terminal of circuit 1 is electrically connected to the high-voltage terminal of discharge switch G, and the low-voltage terminal of discharge switch G forms an inductance with the waveform. L The high-voltage electrical connection forms an inductance waveform. L The low-voltage end forms or protects the resistor with the first waveform. R The electrical connection of the high-voltage end of the PS, the first waveform forming or protection resistor. R The other end of ps is connected to the closing resistor. Z One end of r is electrically connected; load Z The other end of r is connected to the low-voltage end of the controllable high-voltage DC charging power supply 1 or the energy storage capacitor. C 1. Electrical connection at the low-voltage end; simultaneously, an inductance is formed between the discharge switch G and the waveform. L Electrical connections and energy storage capacitors C A second waveform forming or protection resistor is also connected in parallel between the low voltage terminals of 1. R po.

[0048] (II) Circuit analysis of the voltage across the closing resistor Zr:

[0049] To obtain the analytical expression for the voltage across the closing resistor Zr, at the instant the discharge switch G is turned on, Figure 2a The generation loop can be used Figure 2b The circuit shown is equivalent and analyzed. Figure 2b In the middle, energy storage capacitor C 1. Resistor formed or protected with the second waveform R The parallel branch of po can be equivalent to an energy storage capacitor. C 1 and waveform form resistance The series branches. Among them,

[0050]

[0051]

[0052] make: Therefore, we can obtain Figure 2b The differential equation of the circuit shown is:

[0053] (1)

[0054] Solving equation (1) yields the characteristic roots of equation (1):

[0055] (2)

[0056] Therefore, the solution to equation (1), i.e., the current in the impact discharge circuit, is:

[0057] (3)

[0058] Based on the initial conditions of the impulse discharge circuit:

[0059] (4)

[0060] The coefficients in equation (3) can be obtained as follows:

[0061] (5)

[0062] Therefore, the current in the impulse discharge circuit is:

[0063] (6)

[0064] Based on the waveform parameters of the 1.2 / 50μs lightning impulse voltage and the closing resistor Z Based on the characteristics of pure resistance, it can be concluded that current flows through the closing resistor... Z The impulse current wave of r has the same waveform parameters as the voltage waveform at both ends; both are unipolar double exponential waves with fast rise time and slow fall time. This means that lightning impulse discharge unit 2 is in an overdamped oscillating state. The current expression in lightning impulse discharge unit 2 is:

[0065] (7)

[0066] Then it acts on the closing resistor Z The voltage expression across r is:

[0067] (8)

[0068] Next, according to expression (8), the effect on the closing resistor can be calculated numerically. Z The rise time and half-peak time of the impulse voltage waveform at both ends r. Where, rise time... T 1 and half peak timeT 2 are respectively 1.67× ( t 90% - t 30% The time interval between the origin of the impulse voltage and the moment when the voltage drops to 50% of its peak value.

[0069] See Figure 3 The present invention relates to the energy storage capacitor in the lightning impulse discharge unit 2 of the closing resistor for a circuit breaker, which is used in the lightning impulse withstand test. C 1. Waveform forming inductance L and the first waveform to form or protect the resistor R ps, second waveform forming or protection resistor R The selection method for po. Since the waveform parameters of lightning impulse voltage must be based on the specifications of the International Electrotechnical Commission (IEC) or national standards, the rise time of the lightning impulse voltage waveform... T The allowable deviation for 1 is ±30%, and the allowable deviation for the half-peak time is ±20%, thus obtaining the closing resistor values ​​for different resistance values. Z Methods for designing and selecting parameters for the impulse generation circuit in a lightning impulse withstand voltage test. This includes consideration of closing resistors with different resistance values. Z r load, energy storage capacitor C 1 and waveform form an inductance L The selection should be made within the range of the upper and lower bounds.

[0070] This invention discloses a measurement and control method for lightning impulse withstand testing of closing resistors for circuit breakers. The computer-based measurement and control management system 4 mainly consists of a pulse voltage divider 5, an oscilloscope 6, a control unit 7, and a computer 8. The computer 8 communicates with the control unit 7 via optical fiber, and the computer 8 communicates with the oscilloscope 6 via Ethernet output. This method achieves both electromagnetic compatibility in strong pulse electromagnetic environments and rapid control and data transmission.

[0071] The measurement and control process is as follows:

[0072] Controllable high-voltage DC charging power supply 1 to the energy storage capacitor of lightning impulse discharge unit 2 C The charging of 1 can be directly controlled by the computer measurement and control management system 4 through communication, or it can be achieved by the computer through the control method of the control unit.

[0073] The measurement and control management process of the computer measurement and control management system 4 is as follows:

[0074] like Figure 4 As shown, based on the tested closing resistance Z Choose or prepare a suitable test circuit based on the resistance value of r; in the closing resistor circuit ZOn the human-machine interface for the lightning impulse voltage withstand test, the test mode is set, including the polarity of the impulse pulse and the number of impulses.

[0075] Based on the closing resistor Z The voltage amplitude of the withstand test of r is automatically converted into the discharge voltage of the lightning impulse discharge circuit based on the output efficiency of the impulse discharge unit.

[0076] Starting closing resistor Z The operation of the lightning impact tolerance test software.

[0077] The computer-controlled measurement and control management system automatically controls the energy storage capacitor of the controllable high-voltage DC charging power supply 1 to the lightning impulse discharge unit 2. C The charging process of 1 can be automatically tracked by the energy storage capacitor. C 1. Real-time status of the charging voltage at both ends, when the energy storage capacitor... C When the charging voltage at both ends of the 1 terminal reaches the preset test conditions, it can automatically give a control pulse to the discharge switch G of the lightning impulse discharge unit 2 to break down and conduct.

[0078] Energy storage capacitor C The electrical energy of 1 passes through the discharge switch G and forms an inductor with the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po discharges to the closing resistor Zr and applies the lightning impulse voltage to the closing resistor. Z r on.

[0079] The lightning impulse voltage waveform applied across the closing resistor Zr is extracted and recorded by the pulse voltage divider 5 and the oscilloscope 6, and processed and analyzed by the data transmission between the computer 8 and the oscilloscope 6.

[0080] When a lightning impulse voltage is applied across the closing resistor Zr, such as... Figure 5 When the waveform shown is distorted, the computer measurement and control management system 4 automatically provides the closing resistance. Z criterion for surface flashover discharge, closing resistance Z The impulse voltage withstand test of r is stopped, and the closing resistance is recorded. Z The maximum impulse voltage value that prevents flashover is its lightning impulse voltage withstand value.

[0081] Based on the designed discharge circuit configuration, a theoretical analysis of the correlation between the transient voltage waveform across the load terminals of the closing resistor and the circuit parameters is conducted to obtain the circuit parameter design principles for lightning impulse withstand tests of closing resistors with different resistance values. By implementing and controlling components such as energy storage capacitors, discharge switches, waveform forming inductors, and discretely adjustable resistors, the requirements for lightning impulse voltage test waveforms of closing resistors with different resistance values ​​are met.

[0082] This invention relates to a lightning impulse withstand test device for circuit breakers. The test method for the lightning impulse withstand voltage of the closing resistor conforms to the lightning impulse voltage test method specified in IEC 60060-1, and can realize the test procedures A, B, and C of the withstand voltage test. Appropriate energy storage capacitors, waveform forming inductors, and resistors can be adjusted according to the resistance value of the closing resistor to ensure that the impulse voltage waveform parameters applied across the load with different resistance values ​​meet the allowable deviation requirements of the lightning impulse voltage waveform parameters. Applicable loads can include not only typical closing resistor values, such as 5 ohms and 6 ohms, but also proportional units of closing resistors connected in series.

[0083] To simulate the SF6 operating environment of circuit breakers in high-voltage transmission systems, the closing resistor is placed in an SF6 environment, or in other environments such as N2 or oil, during the lightning impulse withstand voltage test. The lightning withstand voltage is determined from a pre-declared lightning withstand voltage. U LI The test begins at 50% of the rated voltage. If the test passes, the voltage is then increased in increments of 10% until a surface flashover occurs at the closing resistor. The maximum voltage that the closing resistor can withstand is taken as its maximum lightning impulse withstand voltage. To prevent interference and damage to the energy storage capacitor, measurement system, and computer management system caused by surface flashover breakdown or rupture of the closing resistor, protective measures are installed in the lightning impulse voltage generation circuit to prevent surface flashover or explosive open circuit of the closing resistor load. This avoids damage or operational accidents caused by overcurrent in the generation circuit and measurement and control system, or by the inability to release stored energy.

[0084] The present invention has been described in detail with reference to the above embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific embodiments of the present invention without departing from the spirit and scope of the present invention, and such modifications or equivalent substitutions should be covered within the scope of the claims of this patent.

Claims

1. A closing resistance lightning impulse withstand test device for circuit breakers, characterized by: It includes a controllable high-voltage DC charging power supply (1), a lightning impulse discharge unit (2), a closing resistor load (3), and a computer measurement and control management system (4). The controllable high-voltage DC charging power supply (1) consists of an adjustable high-voltage DC charging power supply (1-1) and a DC voltage divider (1-2). The controllable high-voltage DC charging power supply (1) is used to charge the energy storage capacitor element of the lightning impulse discharge unit (2). The lightning impulse discharge unit (2) includes an energy storage capacitor. C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po and closing resistor Z r; closing resistor Z r is the closing resistor load (3), and the energy storage capacitor is the energy storage capacitor. C 1. Inductance is formed by the discharge switch G and the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po closing resistor Z The r-discharge generates a lightning impulse voltage and applies it across the closing resistor load, producing a lightning impulse voltage waveform that meets the standard requirements; The current expression in the lightning impulse discharge unit (2) is: （7） Then it acts on the closing resistor Z The voltage expression across r is: （8） Acting on the closing resistor Z The rise time of the impulse voltage waveform at both ends r T 1 and half peak time T 2 are respectively 1.67× ( t 90% - t 30% The time interval between the origin of the impulse voltage and the moment when the voltage drops to 50% of its peak value; In the formula, The total resistance of the equivalent circuit. The total capacitance of the equivalent circuit. The charging / discharging voltage across the energy storage capacitor in the lightning impulse discharge unit (2) is the voltage across the capacitor. t 90% and t 30% These are the times corresponding to the 90% peak value and the 30% peak value of the output voltage wave of the lightning impulse discharge unit (2), respectively; The computer measurement and control management system (4) is used to automatically monitor the charging process of the lightning impulse test of the closing resistor, automatically control the process of the lightning impulse withstand test of the closing resistor, realize the analysis and judgment of the results of the lightning impulse withstand test of the closing resistor, and extract, record, store, query and output test reports of the lightning impulse withstand test signal of the closing resistor.

2. The lightning impulse withstand test device for closing resistor of circuit breaker as described in claim 1, characterized in that: The energy storage capacitor C 1. Both ends are connected in parallel to the high voltage end and low voltage end of the controllable high voltage DC charging power supply (1), and the energy storage capacitor C The high-voltage terminal of circuit 1 is electrically connected to the high-voltage terminal of discharge switch G, and the low-voltage terminal of discharge switch G forms an inductance with the waveform. L The high-voltage electrical connection forms an inductance waveform. L The low-voltage end forms or protects the resistor with the first waveform. R The electrical connection of the high-voltage end of the PS, the first waveform forming or protection resistor. R The other end of ps is connected to the closing resistor. Z One end of r is electrically connected; load Z The other end of r is connected to the low-voltage end of the controllable high-voltage DC charging power supply (1) or the energy storage capacitor. C 1. Low-voltage electrical connection, second waveform forming or protection resistor. R po is connected in parallel to the discharge switch G, forming an inductance with the waveform. L Electrical connections and energy storage capacitors C Between the low-voltage ends of 1.

3. The lightning impulse withstand test device for closing resistor of circuit breaker as described in claim 2, characterized in that: The energy storage capacitor C 1. Discharge switch G, waveform forming inductor L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po are all components with discretely adjustable parameters.

4. The lightning impulse withstand test device for closing resistor of circuit breaker as described in claim 1, characterized in that: The computer measurement and control management system (4) includes a pulse voltage divider (5), an oscilloscope (6), a control unit (7), and a computer (8). The control unit (7) consists of a charging voltage monitoring circuit (7-1) and a programmable controller (7-2) to realize the process of automatically controlling the lightning impulse withstand test of the closing resistor. The lightning impulse voltage applied across the closing resistor load (3) is extracted and recorded by the pulse voltage divider (5) and the oscilloscope (6), and the control and data processing of the lightning impulse withstand voltage test of the closing resistor are realized through data communication between the computer (8) and the oscilloscope (6).

5. The lightning impulse withstand test device for closing resistor of circuit breaker as described in claim 4, characterized in that: The computer (8) and the control unit (7) communicate via optical fiber, and the computer (8) and the oscilloscope (6) transmit data via network port.

6. The lightning impulse withstand test device for closing resistor of circuit breaker as described in any one of claims 1-5, characterized in that: The controllable high-voltage DC charging power supply (1) has a human-machine interface, and its output voltage is set through its own human-machine interface or controlled by the computer measurement and control management system (4).

7. A method for lightning impulse withstand test of the closing resistor of a circuit breaker based on the test apparatus described in claim 6, characterized in that... Includes the following steps: (1) Based on the tested closing resistance Z Select a suitable test circuit based on the resistance value of r; set the lightning impulse voltage test mode, including the polarity of the impulse pulse and the number of impulses; and determine the appropriate test circuit based on the closing resistor. Z The withstand voltage amplitude of r is automatically converted into the discharge voltage of the lightning impulse discharge circuit based on the output efficiency of the lightning impulse discharge unit. (2) Start closing resistor Z The lightning impulse withstand test software, computer measurement and control management system (4) automatically controls the controllable high voltage DC charging power supply (1) to the energy storage capacitor of the lightning impulse discharge unit (2). C The charging process of 1 can be automatically tracked by the energy storage capacitor. C 1. Real-time status of the charging voltage at both ends, when the energy storage capacitor... C When the charging voltage at both ends of 1 reaches the preset test conditions, a control pulse is automatically given to the discharge switch G of the lightning impulse discharge unit (2) to break down and conduct. (3) Energy storage capacitor C The electrical energy of 1 passes through the discharge switch G and forms an inductor with the waveform. L First waveform forming or protection resistor R ps, second waveform forming or protection resistor R po discharges to the closing resistor Zr and applies the lightning impulse voltage to the closing resistor. Z The lightning impulse voltage waveform applied across the closing resistor Zr is extracted and recorded by the pulse voltage divider (5) and the oscilloscope (6), and processed and analyzed by the data transmission between the computer (8) and the oscilloscope (6). (4) When the lightning impulse voltage applied across the closing resistor Zr is distorted, the computer measurement and control management system (4) automatically provides the closing resistor value. Z criterion for surface flashover discharge, closing resistance Z The impulse voltage withstand test of r is stopped, and the closing resistance is recorded. Z The maximum impulse voltage value that does not cause flashover is its lightning impulse voltage withstand value. (5) Based on the designed discharge circuit form, conduct a theoretical analysis of the correlation between the transient voltage waveform across the closing resistor load and the circuit parameters.

8. The lightning impulse withstand test method for the closing resistor of a circuit breaker as described in claim 7, characterized in that: From lightning withstand voltage U LI The test begins at 50% of the voltage level. If the test passes, the voltage is then increased in increments of 10% until the closing resistor is reached. Z The maximum voltage that the closing resistor can withstand until a surface flashover occurs is taken as its maximum lightning impulse withstand voltage value.

9. The lightning impulse withstand test method for the closing resistor of a circuit breaker as described in claim 7, characterized in that: In the lightning impulse withstand voltage test of the closing resistor, the closing resistor Z The circuit is placed in an SF6, N2, or oil-filled environment, and is equipped with protective measures to prevent surface flashover or explosive open circuit of the closing resistor load in the lightning impulse voltage generation circuit.

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