CN108318744B - Converter valve thyristor-level damping loop parameter testing device and method - Google Patents
Converter valve thyristor-level damping loop parameter testing device and method Download PDFInfo
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- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
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- G—PHYSICS
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- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
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Abstract
The invention relates to a converter valve thyristor level damping loop parameter testing device and a method, which comprises a control system, a measuring system and a power supply loop, wherein an interface is arranged in the measuring system, negative peak values of voltage at two ends of a sampling resistor and negative peak values of alternating current power supply voltage are collected, and according to the collected values, the damping loop parameters are obtained by calculation by combining the conduction voltage drop of a reverse diode of an energy taking circuit of a thyristor trigger control board, so that the accuracy and reliability of testing of a damping resistor and a capacitance value are ensured.
Description
Technical Field
The invention belongs to the technical field of high-voltage direct-current power transmission, and particularly relates to a converter valve thyristor-level damping loop parameter testing device and method.
Background
Converter valves are important elements in high-voltage direct-current transmission engineering, and are usually formed by connecting multiple thyristors in series due to high voltage level of high-voltage direct-current transmission. The damping loop has the function of ensuring that the voltage between the series thyristors is uniformly distributed, consists of a damping resistor and a damping capacitor, and has important significance on the safe operation of direct current transmission. Therefore, accurate testing of damping loop element parameters is extremely important. However, as a single converter station has thousands of thyristor levels, the measurement of the damping loop parameters is carried out in the process of maintenance.
The traditional method for testing the damping loop of the converter valve mainly utilizes a universal meter, an electric bridge and the like to carry out direct testing, and the method needs to connect a wiring to two ends of a damping capacitor C and a damping resistor R in the converter valve. Because in Thyristor Electronic circuit (TE board) structure converter valve, damping electric capacity C and damping resistance R are located converter valve subassembly both sides respectively, and the wiring is inconvenient, needs a plurality of experimenters cooperation, spends a large amount of time to accomplish.
In recent years, there is also a method of installing the measuring device to the telescopic rod by a part of units to connect the wiring to both ends of the capacitor C and the resistor R when the tester is measuring. Compared with the traditional test method, the method has the advantages that the test speed and the convenience degree are improved. However, during the test, the telescopic rod needs to cross the thyristor, the TE plate, the damping resistor and a high-voltage connection in the valve component, so that the telescopic rod is easy to contact the equipment, other problems are caused, and the safety is poor.
Chinese patent publication No. CN104808070A proposes a damping loop parameter testing method, and as shown in fig. 1, a 50Hz power frequency ac power supply is applied to both ends of a thyristor-level test piece, and a phase difference between voltage and current of the thyristor-level test piece is used to calculate a damping resistance and a damping capacitance, but a thyristor triggering and monitoring electronic device energy-taking circuit connected in series in the damping loop is not considered.
Because the converter valve usually adopts a suspension structure, the connection of the wiring to the damping resistor and the damping capacitor is very inconvenient during impedance test, and the connection of the output of the testing device to the cathode and the anode radiators of the thyristor is simple and easy to operate.
Disclosure of Invention
In order to overcome the defects, the testing method not only accords with the structural design of the converter valve, but also considers the TE plate energy-taking circuit connected in series in the damping loop, has accurate testing result, and is convenient for the field implementation of the converter valve engineering.
The invention aims to provide a converter valve thyristor-level damping loop parameter testing device and method, which are used for solving the problems of inaccurate measurement of damping loop parameters and unsafe testing equipment in the prior art.
In order to solve the technical problem, the invention provides a thyristor-level damping loop parameter testing device for a converter valve, which comprises a control system and a measuring system, wherein the control system is connected with the measuring system, the thyristor-level damping loop parameter testing device also comprises a power supply loop used for supplying power to a thyristor level, the power supply loop is used for supplying power to an energy taking circuit connected with a damping resistor, a damping capacitor and a TE plate, and the power supply loop is provided with an alternating current power supply and a sampling resistor; the measuring system is provided with an interface for measuring the voltage at two ends of the sampling resistor and an interface for measuring the voltage of the alternating current power supply.
Furthermore, the power supply loop is also provided with an isolation transformer, and an alternating current power supply is connected with the sampling resistor through an isolation voltage device.
Further, the power supply loop is also provided with a relay.
Furthermore, the measuring system comprises a sampling circuit and a signal conditioning circuit, the sampling circuit is connected with the control system through the signal conditioning circuit, and an interface for measuring the voltages at two ends of the sampling resistor and an interface for measuring the voltage of the alternating current power supply are arranged in the sampling circuit.
Further, the control system comprises a DSP and a display system.
In order to solve the technical problem, the invention further provides a converter valve thyristor-level damping loop parameter testing method, which comprises the following steps:
1) in the converter valve, a damping loop is connected in parallel at two ends of a thyristor, a power supply loop is provided with an alternating current power supply and a sampling resistor, two output terminals of the power supply loop are respectively connected to an anode and a cathode of the thyristor, and when alternating current voltage is applied to the power supply loop, negative peak values of voltage at two ends of the sampling resistor are collected, and negative peak values of the voltage of the alternating current power supply are collected;
2) calculating the phase difference between the current of the power supply loop and the voltage of the alternating current power supply according to the difference value between the sampling time of the negative peak value of the voltage at the two ends of the sampling resistor and the sampling time of the negative peak value of the voltage of the alternating current power supply;
3) and calculating to obtain a damping resistance value and a damping capacitance value according to the negative peak value of the voltage at the two ends of the sampling resistor and the negative peak value of the voltage of the alternating-current power supply, and by combining the conduction voltage drop of a reverse diode in the known TE plate energy-taking circuit and the phase difference.
Furthermore, the power supply loop is also provided with an isolation transformer, and an alternating current power supply is connected with the sampling resistor through an isolation voltage device; and the negative peak value of the alternating current power supply voltage is the negative peak value of the secondary side voltage of the isolation transformer.
Further, the calculation formula of the phase difference in step 2) is as follows:
δ＝t*2π/T
in the formula, δ is the phase difference, T is a sampling period, and T is a difference value between a sampling time of a negative peak value of the voltage at two ends of the sampling resistor and a negative peak value of the voltage of the alternating-current power supply or a sampling time of a secondary side voltage of the isolation transformer.
Further, the calculation formula of the damping resistor and the damping capacitor in the step 3) is as follows:
R＝(Um-Udiode)*RL*cos(t*2π/T)/URlm-RL
C＝URlm/[(Udiode-Um)*RL*sin(t*2π/T)*2πf]
wherein R is a damping resistor, C is a damping capacitor, and UmIs the negative peak value of the AC power supply voltage or the negative peak value of the secondary side voltage of the isolation transformer, RLFor sampling the resistance, URlmFor sampling the negative peak value, U, of the voltage across the resistordiodeAnd f is the frequency of the alternating current power supply.
Further, when the damping resistor is in a set resistor range and the damping capacitor is in a set capacitor range, determining that the thyristor-level damping loop parameter is qualified.
The invention has the beneficial effects that:
the damping loop parameter testing device is simple in structure and comprises a control system, a measuring system and a power supply loop, wherein an interface is arranged in the measuring system, negative peak values of voltages at two ends of a sampling resistor and negative peak values of alternating-current power supply voltages are collected, conduction voltage drop of a reverse diode in a TE plate energy-taking circuit is combined, and damping loop parameters can be calculated according to the collected values, so that the accuracy and reliability of testing of the damping resistor and the capacitance value are guaranteed.
Furthermore, the power supply loop is also provided with an isolation transformer, so that high-frequency noise waves are effectively inhibited from entering the power supply loop, a measuring system can acquire relatively pure negative peak waveforms of voltages at two ends of the sampling resistor, conducting voltage waveforms of a reverse diode in the TE plate energy-taking circuit and negative peak waveforms of secondary side voltages of the isolation transformer, and the precision of calculating the damping resistor and the damping capacitor is improved.
Drawings
FIG. 1 is a system block diagram of a damping loop parameter testing device of the prior art;
FIG. 2 is a system diagram of a damping loop parameter testing device according to the present invention;
FIG. 3 is a schematic diagram of the TE plate energy-taking circuit;
FIG. 4 is a voltage acquisition waveform diagram of a sampling resistor and isolation transformer;
fig. 5 is a vector diagram of damping loop impedance.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings.
Fig. 2 shows a damping loop parameter testing apparatus of the present invention, which includes a control system, a measurement system, and a power supply loop for supplying power to a thyristor level. Wherein the control system is connected with the measuring system, and the power supply loop is provided with an alternating current power supply and a sampling resistor RLThe device comprises an isolation transformer and a relay, wherein one end of the isolation transformer is connected with an alternating current power supply through the relay, and the other end of the isolation transformer is connected with a sampling resistor; the measuring system is provided with a measuring and sampling resistor RLInterface C for negative peak of voltage at two ends2Interface C for measuring the negative peak of the AC supply voltage1. The thyristor level comprises a thyristor VT, and a damping loop formed by connecting energy taking circuits of a damping resistor R and a damping capacitor C, TE in series, and the thyristor VT is connected with the damping loop in parallel.
The testing method realized by the damping loop parameter testing device comprises the following steps:
1) controlling an alternating current power supply to be applied to a thyristor level, collecting negative peak values of voltages at two ends of a sampling resistor, and collecting the negative peak values of the alternating current power supply voltage;
2) calculating the phase difference between the current of the power supply loop and the voltage of the alternating current power supply according to the difference value between the sampling time of the negative peak value of the voltage at the two ends of the sampling resistor and the sampling time of the negative peak value of the voltage of the alternating current power supply;
3) obtaining a damping resistor and a damping capacitor according to the negative peak value of the voltage at two ends of the sampling resistor, the negative peak value of the voltage of the alternating-current power supply, the conduction voltage drop of a reverse diode in the known TE plate energy taking circuit and the phase difference;
4) and when the damping resistor is in a set resistor range and the damping capacitor is in a set capacitor range, judging that the parameters of the thyristor-level damping loop are qualified.
The testing device disclosed by the invention is simple in structural principle, can calculate and obtain damping loop parameters by collecting the negative peak values of the voltages at two ends of the sampling resistor and the negative peak value of the voltage of the alternating-current power supply and combining the acquired values with the conduction voltage drop of the reverse diode in the energy-taking circuit of the TE plate, and ensures the accuracy and reliability of the testing of the damping resistor and the capacitance value, and is low in price and safe and convenient to operate.
In order to facilitate the testing of the wiring, the testing device applies a 50Hz power frequency AC power supply to both ends of the thyristor stage to be tested. Because the thyristor is in an off state, the secondary side of the transformer is equivalent to a damping loop, a TE plate and a sampling resistor RLThe series circuit of (1). As shown in fig. 2, when the current of the power supply loop is positive, the energy-taking circuit of the TE plate is connected in series to the damping loop; when the current of the power supply loop is negative, the reverse diode of the TE plate is conducted, and the energy taking circuit of the TE plate is bypassed. The invention utilizes the characteristic that a reverse diode of a TE plate is conducted when the current of a thyristor damping loop is in a negative phase, and negative peak value U of the voltage at two ends of a sampling resistor is measuredRlmCalculating the negative peak value I of the loop currentmThe calculation formula is Im＝URlm/RL. Meanwhile, measuring the negative peak value U of the secondary side voltage of the isolation transformermAnd the conduction voltage drop U of the reverse diode in the TE plate energy taking circuitdiodeCombined with URlmAnd UmAnd calculating the damping loop parameter according to the generated time difference t.
And according to the acquired values, calculating the loop impedance in the power supply loop by the following formula:
Z＝│Z│cosδ+j│Z│sinδ
│Z│＝(Um-Udiode)*RL/URlm
Z＝R+RL-j/2πfC
in the formula, Z is loop impedance, Z is loop impedance amplitude, R is damping resistance, C is damping capacitance, f is acquisition frequency, preferably 50Hz power frequency, and delta is phase difference between power supply loop current and secondary side voltage of isolation transformer, because sampling resistance RLFor high-precision non-inductive sampling resistor, the phase of loop current and the negative peak value U of voltage at two ends of the sampling resistorRlmIs equal to the phase difference between the supply loop current and the secondary side voltage of the isolation transformer, and is equal to the negative peak value U of the voltage at the two ends of the sampling resistorRlmSecondary side voltage U of isolation transformermThe formula (2) is as follows:
δ＝t*2π/T
in the formula, T is a sampling period, which is 20ms, and T is a difference value between a sampling time of a negative peak value of the voltage at two ends of the sampling resistor and a sampling time of a secondary side voltage of the isolation transformer, as shown in fig. 5.
And combining the formula to obtain a calculation formula of the damping resistor and the damping capacitor:
R＝(Um-Udiode)*RL*cos(t*2π/T)/URlm-RL
C＝URlm/[(Udiode-Um)*RL*sin(t*2π/T)*2πf]
in the formula of UmIs the negative peak value of the AC power supply voltage or the negative peak value of the secondary side voltage of the isolation transformer, RLFor sampling the resistance, URlmFor sampling the negative peak value, U, of the voltage across the resistordiodeAnd f is the frequency of the alternating current power supply.
And after the damping resistance and the damping capacitance are calculated, judging whether the test result is qualified according to the set parameter range, and displaying through a display system. For example, when the damping resistor R is within a set resistance range and the damping capacitor C is within a set capacitance range, the damping loop parameter of the thyristor level to be tested is determined to be qualified, and if any parameter of the damping resistor and the damping capacitor is not within the set parameter range, the damping loop parameter is determined to be unqualified.
The invention has convenient wiring and accurate and reliable test result. The control system applies a 50Hz power frequency alternating current power supply to two ends of the tested thyristor level through the isolation transformer, so that a backward diode in the TE plate energy taking circuit is in a conducting state, a loop current signal and an isolation transformer secondary side voltage signal are measured, and the numerical values of the damping resistor and the damping capacitor can be calculated according to the negative peak values of the current signal and the voltage signal and by combining the phase difference. The thyristor-level damping loop parameter testing device for the converter valve has the advantages of simple structure, convenience in wiring and accurate and reliable testing result.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (8)
1. A converter valve thyristor-level damping loop parameter testing method is characterized by comprising the following steps:
1) applying a power supply loop to two ends of a damping loop connected in series, wherein the power supply loop is provided with an alternating current power supply and a sampling resistor, and when the power supply loop applies alternating current voltage, acquiring negative peak values of the voltage at two ends of the sampling resistor and acquiring the negative peak values of the voltage of the alternating current power supply;
2) calculating the phase difference between the current of the power supply loop and the voltage of the alternating current power supply according to the difference value between the sampling time of the negative peak value of the voltage at the two ends of the sampling resistor and the sampling time of the negative peak value of the voltage of the alternating current power supply;
3) calculating to obtain a damping resistance value and a damping capacitance value according to the negative peak value of the voltage at two ends of the sampling resistor and the negative peak value of the voltage of the alternating-current power supply, and by combining the conduction voltage drop of a reverse diode in the known TE plate energy-taking circuit and the phase difference;
the calculation formula of the phase difference in the step 2) is as follows:
δ＝t*2π/T
in the formula, δ is the phase difference, T is a sampling period, and T is a difference value between the sampling time of the negative peak value of the voltage at two ends of the sampling resistor and the negative peak value of the voltage of the alternating-current power supply or the sampling time of the secondary side voltage of the isolation transformer;
the calculation formula of the damping resistor and the damping capacitor in the step 3) is as follows:
R＝(Um-Udiode)*RL*cos(t*2π/T)/URlm-RL
C＝URlm/[(Udiode-Um)*RL*sin(t*2π/T)*2πf]
wherein R is a damping resistor, C is a damping capacitor, and UmIs the negative peak value of the AC power supply voltage or the negative peak value of the secondary side voltage of the isolation transformer, RLFor sampling the resistance, URlmFor sampling the negative peak value, U, of the voltage across the resistordiodeAnd f is the frequency of the alternating current power supply.
2. The method for testing the parameters of the thyristor-level damping loop of the converter valve according to claim 1, wherein the power supply loop is further provided with an isolation transformer, and an alternating current power supply is connected with the sampling resistor through an isolation voltmeter; and the negative peak value of the alternating current power supply voltage is the negative peak value of the secondary side voltage of the isolation transformer.
3. The method for testing the thyristor-level damping loop parameter of the converter valve according to claim 1, wherein when the damping resistor is within a set resistor range and the damping capacitor is within a set capacitor range, the thyristor-level damping loop parameter is determined to be qualified.
4. The converter valve thyristor-level damping loop parameter testing device special for the testing method of claim 1 comprises a control system and a measuring system, wherein the control system is connected with the measuring system, and the testing device is characterized by further comprising a power supply loop used for supplying power to the thyristor level, the power supply loop is used for supplying power to an energy taking circuit connected with a damping resistor, a damping capacitor and a TE plate, and the power supply loop is provided with an alternating current power supply and a sampling resistor; the measuring system is provided with an interface for measuring the voltage at two ends of the sampling resistor and an interface for measuring the voltage of the alternating current power supply.
5. The thyristor-level damping loop parameter testing device of the converter valve according to claim 4, wherein the power supply loop is further provided with an isolation transformer, and an alternating current power supply is connected with the sampling resistor through an isolation voltmeter.
6. The converter valve thyristor-level damping loop parameter testing device according to claim 5, wherein the power supply loop is further provided with a relay.
7. The thyristor-level damping loop parameter testing device of the converter valve according to claim 4, wherein the measuring system comprises a sampling circuit and a signal conditioning circuit, the sampling circuit is connected with the control system through the signal conditioning circuit, and the sampling circuit is provided with the interface for measuring the voltage at two ends of the sampling resistor and the interface for measuring the voltage of the alternating-current power supply.
8. The thyristor-level damping loop parameter testing device of claim 4, wherein the control system comprises a DSP and a display system.
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| CN109239557B (en) * | 2018-10-26 | 2020-11-24 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Leakage current calculation method for thyristor out-of-band circuit to carry out voltage endurance test |
| CN112630540B (en) * | 2019-09-24 | 2022-07-19 | 华润微集成电路(无锡)有限公司 | Inductance quality factor measuring method, corresponding measuring circuit and application thereof |
| CN112269066B (en) * | 2020-09-14 | 2022-05-13 | 中国南方电网有限责任公司超高压输电公司广州局 | Method for measuring non-disconnection parameters of core device of voltage-sharing capacitor circuit of converter valve |
| CN112269062B (en) * | 2020-09-14 | 2022-09-09 | 中国南方电网有限责任公司超高压输电公司广州局 | Valve section module element impedance tester |
| CN112505496B (en) * | 2020-11-03 | 2021-08-27 | 西安交通大学 | Thyristor real-time diagnosis and prediction method for insulation abnormity in converter valve |
| CN115015729B (en) * | 2022-06-30 | 2024-03-22 | 中国电力科学研究院有限公司 | Test loop, method and system for checking performance of thyristor converter valve and damping loop thereof |
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