A circuit breaker closing resistor operating impulse voltage loop parameter design method and operating impulse withstand test device

Abstract

This invention discloses a method for designing the operating impulse voltage circuit parameters of a circuit breaker closing resistor and an operating impulse withstand test device. Based on the transient analysis of the operating impulse voltage generation circuit, the correlation between the voltage characteristics across the circuit breaker closing resistor and the load resistance and circuit parameters is obtained. A design method suitable for the operating impulse withstand voltage generation circuit parameters with different resistance values ​​is established. On this basis, an operating impulse withstand test device for the circuit breaker closing resistor is established, solving the problem that existing operating impulse high voltage test systems cannot perform operating impulse withstand voltage tests on resistive loads, and providing 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 testing equipment for ultra-high voltage equipment, and particularly to a method for designing circuit parameters of the closing resistor operating impulse voltage circuit for circuit breakers and a testing device for operating impulse withstand. 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] Linear resistors are crucial protective devices during circuit breaker closing and are an effective measure to limit operational overvoltages. Currently, my country almost entirely relies on imports for the closing resistors used in high-voltage transmission lines. Research on the fabrication of carbon-ceramic linear resistors and zinc oxide linear resistors has begun in my country, but no substantial technological breakthroughs have been achieved. It is particularly noteworthy that high-voltage testing technology for linear resistors used in ultra-high-voltage and extra-high-voltage transmission lines is still lacking both domestically and internationally.

[0004] Switching impulse withstand voltage testing is a critical test item for power equipment. However, there are no relevant International Electrotechnical Commission (IEC) or national standards to refer to for the switching impulse withstand voltage testing of circuit breaker closing resistance. In high-voltage insulation testing, MARX switching 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 switching impulse generators are mainly designed for high-resistance test objects such as electrical insulation materials and power equipment. They are not suitable for switching impulse withstand voltage testing of closing resistance and similar power equipment or devices, primarily because the closing resistance of circuit breakers is normally low-resistance. Test results show that when existing MARX switching impulse generators are applied to the closing resistance, the waveform of the impulse voltage applied to the closing resistance load will be significantly distorted. Therefore, research on the design of high-voltage switching impulse withstand voltage test circuits, test techniques, and the development of test devices for circuit breaker closing resistance 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] The purpose of this invention is to provide a method for designing the operating impulse voltage circuit parameters of a circuit breaker closing resistor and an operating impulse withstand test device, and to establish a design method and test device for an impulse generation circuit suitable for operating impulse withstand voltages of closing resistors with different resistance values.

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

[0007] A method for designing the parameters of the operating impulse voltage circuit for a circuit breaker closing resistor is characterized by: theoretical analysis of the correlation between the transient voltage waveform across the load of the closing resistor and the circuit parameters based on the form of the operating impulse voltage generation circuit; the operating impulse voltage generation circuit consists of an energy storage capacitor C1, a waveform forming inductor L, a first waveform forming or protection resistor Rps, and a second waveform forming or protection resistor Rpo; through analysis of the transient process of the generation circuit, the relationship between the waveform parameters of the impulse voltage applied across the closing resistor Zr and the resistance value of the closing resistor Zr and the circuit parameters is obtained; and the parameter design principles for the operating impulse voltage circuit of the closing resistor with different resistance values ​​are obtained.

[0008] Furthermore, in the operating impulse voltage generation circuit, the high-voltage terminal of the energy storage capacitor C1 is electrically connected to the high-voltage terminal of the discharge switch G, the low-voltage terminal of the discharge switch G is electrically connected to the high-voltage terminal of the waveform adjustment inductor L, the low-voltage terminal of the waveform adjustment inductor L is electrically connected to the high-voltage terminal of the first waveform forming or protection resistor Rps, the other end of the first waveform forming or protection resistor Rps is electrically connected to one end of the closing resistor Zr; the other end of the closing resistor Zr is electrically connected to the low-voltage terminal of the energy storage capacitor C1; and a second waveform forming or protection resistor Rpo is connected in parallel between the electrical connection point between the discharge switch G and the adjustment inductor L and the low-voltage terminal of the energy storage capacitor C1.

[0009] Furthermore, the current expression in the operating impulse voltage generation circuit is as follows:

[0010]

[0011] The voltage expression across the closing resistor Zr is:

[0012]

[0013] In the formula, U0 is the charging / discharging voltage across the energy storage capacitor C1 in the operating impulse voltage generation circuit.

[0014] A circuit breaker closing resistor operating impulse withstand test device includes a controllable high-voltage DC charging power supply, an operating impulse discharge unit, a closing resistor load, and a computer measurement and control management system.

[0015] 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 operating impulse discharge unit.

[0016] The operation impulse discharge unit is an operation impulse voltage generation circuit, the closing resistor Zr is a closing resistor load, and the energy storage capacitor C1 discharges to the closing resistor Zr through the discharge switch G and the waveform forming inductor L, the first waveform forming or protection resistor Rps, and the second waveform forming or protection resistor Rpo to generate an operation impulse voltage and apply it to both ends of the closing resistor load.

[0017] The computer-controlled measurement and control management system is used to automatically monitor the charging process of the closing resistor operation impulse withstand test, automatically control the process of the closing resistor operation impulse withstand test, realize the analysis and judgment of the closing resistor operation impulse withstand test results, and extract, record, store, query and output test reports of the closing resistor impulse withstand voltage test signals.

[0018] Furthermore, the two ends of the energy storage capacitor C1 are connected in parallel with the high-voltage and low-voltage ends of the adjustable high-voltage DC charging power supply. The high-voltage end of the energy storage capacitor C1 is electrically connected to the high-voltage end of the discharge switch G. The low-voltage end of the discharge switch G is electrically connected to the high-voltage end of the waveform forming inductor L. The low-voltage end of the waveform forming inductor L is electrically connected to the high-voltage end of the first waveform forming or protection resistor Rps. The other end of the first waveform forming or protection resistor Rps is electrically connected to one end of the closing resistor Zr. The other end of the load Zr is electrically connected to the low-voltage end of the controllable high-voltage DC charging power supply or the low-voltage end of the energy storage capacitor C1. The second waveform forming or protection resistor Rpo is connected in parallel between the discharge switch G and the waveform forming inductor L at the electrical connection point and the low-voltage end of the energy storage capacitor C1.

[0019] Furthermore, the energy storage capacitor C1, the discharge switch G, the waveform forming inductor L, the first waveform forming or protection resistor Rps, and the second waveform forming or protection resistor Rpo are all components with discretely adjustable parameters.

[0020] 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 closing resistor operation impulse withstand test; the operation 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 closing resistor lightning impulse withstand voltage test are realized through data communication between the computer and the oscilloscope.

[0021] This invention presents a design method for the operating impulse voltage circuit parameters of a circuit breaker's closing resistor. Based on the designed operating impulse voltage generation circuit configuration, it performs a theoretical analysis of the correlation between the transient voltage waveform across the closing resistor load and the circuit parameters. This yields the design principles for circuit parameters used in operating impulse withstand tests of closing resistors with different resistance values. Through the implementation and control of energy storage capacitors, discharge switches, waveform adjustment inductors, and discretely adjustable resistors, the requirements for the operating impulse voltage test waveform of closing resistors with different resistance values ​​are met. This solves the problem that existing high-voltage operating impulse test systems cannot perform operating impulse withstand voltage tests on resistive loads, providing a standardized testing technique for the operational safety of circuit breakers and power systems.

[0022] Based on this, an operational impulse withstand test device for circuit breaker closing resistance was established, and a control method for the operational impulse withstand test of circuit breaker closing resistance was proposed. The test method and test device can be used in similar scenarios such as resistive load operational impulse withstand voltage test in the power, communication and other fields.

[0023] To prevent surface flashover or rupture of the closing resistor load from interfering with and damaging the energy storage capacitor, measurement system, and computer management system, protective measures are installed in the operating impulse voltage generation circuit to prevent surface flashover or explosion of the closing resistor load. This avoids damage caused by overcurrent in the generation circuit and measurement and control system or failure to release stored energy, or operational accidents of the closing resistor operating impulse withstand test system. Attached Figure Description

[0024] Figure 1a This is a structural diagram of the impulse voltage generation circuit for the impulse withstand test of the closing resistor of a circuit breaker according to the present invention;

[0025] Figure 1b This invention relates to an impulse voltage generation circuit for an impulse withstand test of a closing resistor used in a circuit breaker. Figure 1a The equivalent circuit diagram;

[0026] Figure 2a This is a voltage waveform diagram at both ends of the closing resistor when it experiences surface flashover breakdown at the first moment during the operation impulse withstand voltage test of the closing resistor for a circuit breaker according to the present invention.

[0027] Figure 2b This is a voltage waveform diagram at both ends of the closing resistor when a surface flashover breakdown occurs at the second moment during the operation impulse withstand voltage test of the closing resistor of a circuit breaker according to the present invention.

[0028] Figure 2c It is a waveform diagram of the current through the closing resistor when it flashes at different times during the operational impulse withstand test;

[0029] Figure 3This is a diagram showing the selection range of circuit parameters for the impulse withstand voltage test of closing resistors with different resistance values ​​according to the present invention;

[0030] Figure 4 This is a block diagram of the structural composition of a circuit breaker closing resistor operation impulse withstand test device according to the present invention;

[0031] Figure 5 This is a flowchart of the measurement and control process for the operating impulse withstand test of the closing resistor of a circuit breaker according to the present invention.

[0032] In the diagram: 1-Controllable high-voltage DC charging power supply, 1-1-Controllable high-voltage DC charging power supply, 1-2-DC voltage divider, 2-Operating 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

[0033] 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.

[0034] See Figure 1a , Figure 1b This invention discloses a circuit breaker closing resistor operation impulse withstand test device. The operation impulse voltage wave mainly consists of an energy storage capacitor C1, a waveform forming inductor L, a first waveform forming or protection resistor Rps, and a second waveform forming or protection resistor Rpo. By analyzing the transient process of the circuit, the relationship between the impulse voltage waveform parameters applied across the closing resistor Zr and the resistance value of the closing resistor Zr and the circuit parameters is obtained.

[0035] Electrical connections of the generating circuit:

[0036] The high-voltage terminal of the energy storage capacitor C1 is electrically connected to the high-voltage terminal of the discharge switch G. The low-voltage terminal of the discharge switch G is electrically connected to the high-voltage terminal of the waveform adjustment inductor L. The low-voltage terminal of the waveform adjustment inductor L is electrically connected to the high-voltage terminal of the first waveform forming or protection resistor Rps. The other end of the first waveform forming or protection resistor Rps is electrically connected to one end of the closing resistor Zr. The other end of the closing resistor Zr is electrically connected to the low-voltage terminal of the energy storage capacitor C1. At the same time, a second waveform forming or protection resistor Rpo is connected in parallel between the electrical connection point between the discharge switch G and the adjustment inductor L and the low-voltage terminal of the energy storage capacitor C1.

[0037] The principle of the operating impulse withstand voltage generation circuit is to use the charged energy storage capacitor C1 to release the closing resistor Zr instantaneously through the waveform forming inductor L and the first waveform forming or protection resistor Rps and the second waveform forming or protection resistor Rpo when the discharge switch G is turned on, thereby generating an operating impulse pulse across the closing resistor Zr.

[0038] Circuit analysis of the voltage across the closing resistor Zr

[0039] To obtain the analytical expression for the voltage across the closing resistor Zr, at the instant the discharge switch G is turned on, Figure 1a The generation loop can be used Figure 1b The series branch shown is equivalent and analyzed. Figure 1b In the circuit, the parallel branch of the energy storage capacitor C1 and the second waveform forming or protection resistor Rpo can be equivalent to the energy storage capacitor C1 and the waveform forming resistor R'. po The series branches. Among them,

[0040]

[0041]

[0042] Let: R = R' po +R ps +Z r Therefore, we can obtain Figure 2b The differential equation of the circuit shown is:

[0043]

[0044] Solving equation 1 yields the characteristic roots of equation 1 as follows:

[0045]

[0046] Therefore, the current in the impulse voltage generation circuit of equation 1 is:

[0047]

[0048] Based on the initial conditions of the operating impulse voltage generation circuit:

[0049]

[0050] The coefficients in equation 3 can be obtained as follows:

[0051]

[0052] Therefore, the current in the circuit generating the operating impulse voltage is:

[0053]

[0054] Based on the waveform parameters of the 250 / 2500μs operating impulse voltage and the purely resistive characteristics of the closing resistor Zr, it can be concluded that the impulse current wave flowing through the closing resistor Zr has the same waveform parameters as the voltage at both ends. Both are unipolar double exponential waves with fast rise time and slow fall time. In other words, the impulse generation circuit 2 is in an overdamped oscillation state.

[0055] The current expression in the impulse voltage generation circuit is:

[0056]

[0057] The voltage expression across the closing resistor Zr is:

[0058]

[0059] Next, according to Expression 8, the peak time and half-peak time of the impulse voltage waveform acting across the closing resistor Zr can be calculated numerically. Wherein, the peak time T... P T1 is the time interval between the apparent origin of the impulse voltage waveform and the peak voltage value, and T2 is the time interval between the apparent origin of the impulse voltage waveform and the moment when the voltage drops to 50% of the peak value.

[0060] In the formula, U0 is the charging / discharging voltage across the energy storage capacitor in the operating impulse voltage discharge unit 2.

[0061] See Figure 2a , Figure 2b , Figure 2c and Figure 3 This invention discloses a method and apparatus for testing the operating impulse withstand voltage of a closing resistor for a circuit breaker. Referring to example 2a, if a surface flashover breakdown occurs in the closing resistor during the test of the operating impulse withstand voltage of the closing resistor load for a circuit breaker, a large impulse voltage will flow through the operating impulse voltage generation circuit. This is significantly different from the current flowing through the Marx generation circuit in traditional high-voltage testing techniques. Figure 2b and Figure 2c The current waveforms of the closing resistor at different times when the operating impulse voltage is applied are shown. It can be seen that when the closing resistor undergoes surface flashover breakdown near the peak of the operating impulse voltage waveform, there will be a large impulse current in the circuit and the impulse current will oscillate for a long time. This brings more factors to consider when selecting the parameters of the components in the operating impulse voltage circuit.

[0062] Energy storage capacitors not only need to have a high withstand voltage, the rated value of which is determined by the maximum withstand voltage of the tested closing resistor element or proportional unit, but also need to withstand nearly 100% reverse polarity current. This is especially important to consider when selecting dry-type metallized film capacitors with poor reverse polarity withstand performance.

[0063] To limit the peak current in the impulse generation circuit when the closing resistor experiences surface flashover breakdown, a circuit design method that combines a first waveform forming or protection resistor Rps with a current-limiting resistor is added to the operating voltage impulse generation circuit. This effectively prevents the impulse generation circuit from evolving into a deeply underdamped oscillating circuit when the closing resistor experiences surface flashover breakdown, thus avoiding high-voltage test accidents.

[0064] Meanwhile, in order to prevent the closing resistor from bursting and opening during the operation impulse withstand voltage process, which would prevent the electric field energy on the energy storage capacitor from being released, a second waveform forming or protection resistor Rpo is also designed in the operation impulse generation circuit.

[0065] The switching impulse voltage waveform parameters must conform to the specifications of the International Electrotechnical Commission (IEC) or national standards: the peak time T1 and its permissible deviation are 250μs ± 20%, meaning the peak time of the switching impulse voltage can be between 200-300μs; the half-peak time and its permissible deviation are 2500μs ± 60%, meaning the half-peak time of the switching impulse voltage can be between 1000-4000μs. This provides a method for designing and selecting parameters for the impulse generation circuit in the switching impulse withstand voltage test for different closing resistor values ​​Zr, such as... Figure 3 As shown. For loads with different closing resistor Zr values, the selection of energy storage capacitor C1 and waveform adjustment inductor L should be within the range of the upper and lower limits of the envelope.

[0066] See Figure 4 The present invention provides a circuit breaker closing resistor operating impulse voltage withstand test device, which mainly consists of a controllable high-voltage DC charging power supply 1, an operating impulse discharge unit 2, a closing resistor load 3, and a computer measurement and control management system 4.

[0067] 1) The controllable high-voltage DC charging power supply 1 mainly consists of an adjustable controllable 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 operating impulse discharge unit 2.

[0068] 2) The operation impulse discharge unit 2 mainly consists of an energy storage capacitor C1, a discharge switch G, a waveform forming inductor L, a first waveform forming or protection resistor Rps, a second waveform forming or protection resistor Rpo, and a closing resistor Zr3. Its main feature is that the energy storage capacitor C1 and the waveform forming inductor L are high-voltage components that can be discretely adjusted. The main function of the operation impulse discharge unit 2 is to generate an operation impulse voltage waveform that meets the standard requirements.

[0069] 3) The computer-controlled measurement and control management unit 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 unit 4 include: ① automatically monitoring the charging process of the closing resistor operation impulse test; ② cooperating with the computer to automatically control the process of the closing resistor operation impulse withstand test; ③ realizing the analysis and judgment of the closing resistor operation impulse withstand test results; ④ extracting, recording, storing, querying, and outputting test reports of the closing resistor impulse withstand voltage test signals.

[0070] Therefore, it can be concluded that the circuit breaker closing resistor operating 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 operating impulse voltage withstand.

[0071] See Figure 5 This invention discloses a method for conducting an operational impulse withstand test on a circuit breaker using a closing resistor. The measurement and control process for the operational impulse withstand test of the closing resistor is as follows:

[0072] (1) The computer measurement and control management system for starting the closing resistor operation impulse withstand test includes the power supply for turning on the control unit oscilloscope 6, control unit 7 and computer 8, and also includes the power supply for turning on the controllable high voltage DC charging power supply 1 and the operation impulse discharge unit 2.

[0073] (2) Set the information and test parameters for the closing resistor operation impulse withstand test on the human-machine interface of the measurement and control system for the Zr operation impulse withstand test of the closing resistor circuit, including but not limited to:

[0074] 1) Set the test environment information, including date, temperature, humidity, test personnel, etc.

[0075] 2) Set the product information of the tested closing resistor, which may include production batch, specifications, etc.

[0076] 3) Select or prepare a suitable test circuit based on the resistance value of the test closing resistor Zr.

[0077] 4) Set the mode of the operating impulse voltage test, including the polarity of the impulse pulse and the number of impulses.

[0078] 5) Based on the voltage amplitude of the withstand test of the closing resistor Zr, and based on the output efficiency of the operation impulse discharge unit, it is automatically converted into the discharge voltage of the operation impulse voltage generation circuit.

[0079] 6) Set the calibration factor of the pulse voltage sensor for the closing resistor operation impulse withstand test;

[0080] 7) Set the scale of the oscilloscope for operating impulse voltage measurement. The computer measurement and control system will also automatically set the oscilloscope scale according to the set discharge voltage amplitude.

[0081] (3) Run the control and management software for the closing resistor Zr operation impact tolerance test.

[0082] (4) The computer measurement and control management unit 4 automatically controls the charging process of the energy storage capacitor C1 of the controllable high-voltage DC charging power supply 1 to the operation impulse discharge unit 2, and can automatically track the real-time status of the charging voltage across the energy storage capacitor C1. When the charging voltage across the energy storage capacitor C1 reaches the preset test conditions, the control unit 7 sends a discharge pulse to cause the discharge switch G of the operation impulse discharge unit 2 to break down and conduct. The generated operation impulse pulse is applied to the closing resistor Zr.

[0083] (5) The computer measurement and control management unit 4 extracts and records the pulse voltage divider and oscilloscope, and processes and analyzes the operation impact waveform through data transmission between the computer and the oscilloscope.

[0084] (6) When the operating impulse voltage applied across the closing resistor Zr is distorted, the computer measurement and control management unit 4 automatically provides the control criteria for the surface flashover breakdown of the closing resistor Zr, displays and stores the test data and waveforms, and stops the operating impulse withstand test of the closing resistor Zr.

[0085] (7) If the closing resistor Zr passes the operation impulse withstand test, the computer measurement and control unit 4 displays and stores the test data and waveforms, and starts the operation impulse voltage test under the next preset conditions.

[0086] Repeat steps 5) to 7) until the closing resistor experiences surface flashover breakdown. Record the maximum operating impulse voltage value at which the closing resistor Zr does not flashover; this is its operating impulse voltage withstand value.

[0087] 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 method of designing the operating impulse voltage circuit parameters of a closing resistor for a circuit breaker, characterized in that: Based on the configuration of the switching impulse voltage generation circuit, a theoretical analysis is performed on the correlation between the transient voltage waveform across the closing resistor load and the circuit parameters. The switching impulse voltage generation circuit consists of an energy storage capacitor. C 1. Waveform forming inductance L And the first waveform forms or protects the resistor R ps, second waveform forming or protection resistor R The circuit consists of: PO; through analysis of the transient process of the circuit, the relationship between the waveform parameters of the impulse voltage applied across the closing resistor Zr and the resistance value of the closing resistor Zr and the circuit parameters is obtained; the parameter design principles for the impulse voltage circuit of the closing resistor with different resistance values ​​are obtained. The current expression in the operating impulse voltage generating circuit is: (7) The voltage expression acting on the closing resistor Z r is as follows: (8) In the formula, , , For the energy storage capacitor in the operating impulse voltage generation circuit C 1. The charging / discharging voltage at both ends.

2. The method of designing the closing resistor operating impulse voltage circuit parameters for a circuit breaker as defined in Claim 1, characterized by: Energy storage capacitor in the operating impulse voltage generation circuit 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 is connected to the waveform adjustment inductor. L Electrical connection at the high-voltage end, waveform adjustment inductor L The low-voltage end forms a protective resistor with the first waveform. R The electrical connection of the high-voltage side of the PS, the first waveform forming or protection resistor. R The other end of ps is electrically connected to one end of the closing resistor Zr; the other end of the closing resistor Zr is connected to the energy storage capacitor. C Electrical connection of the low-voltage side of 1; discharge switch G and adjusting inductor L Electrical connections and energy storage capacitors C A second waveform forming or protection resistor is connected in parallel between the low-voltage terminals of 1. R po.

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