A method and apparatus for testing a thyristor valve assembly

Abstract

The application relates to the technical field of high-voltage direct current transmission, and discloses a test method and device for a thyristor converter valve assembly, wherein a first electrode and a third electrode are arranged at two ends of the converter valve assembly to be tested, and a second electrode is arranged at a conductive connection between two thyristor stages in the middle; the test is performed as follows: while a conducting signal is sent to the thyristor stages, positive and negative voltages are input into a section between the first electrode and the second electrode and between the third electrode and the second electrode; the currents in the loops of the first electrode and the second electrode and the third electrode and the second electrode are detected in real time, and whether the converter valve assembly is conducting is judged. The test voltage drop is halved, the safety risk brought by high-voltage test is reduced, the design volume of the test device is reduced, the design weight of the test device is reduced, the thyristor stage triggering function test of the component level is realized, and the overall triggering function test efficiency of the converter valve is improved by several times.

Description

Technical Field

[0001] This invention belongs to the field of high voltage direct current transmission technology, specifically relating to a testing method and apparatus for a thyristor converter valve assembly. Background Technology

[0002] The converter valve is mainly composed of valve assemblies (valve sections) connected in series; each valve assembly (valve section) is composed of several thyristor stages connected in series. Due to different technical approaches, the number of thyristor stages contained in the valve assembly (valve section) varies. It is mainly divided into two categories: small assembly (valve section) and large assembly (valve section). Small assembly (valve section) generally has 7 to 9 stages, while large assembly (valve section) generally has 11 to 15 stages.

[0003] The converter valve is a core component of high-voltage direct current (HVDC) transmission projects, and its operational reliability directly determines the normal operation of the entire HVDC transmission system. Therefore, under normal circumstances, a power outage maintenance is required annually to ensure that all functions of the converter valve are normal and its performance is good. Among the most crucial tasks in the annual maintenance is the thyristor-level triggering test, which aims to verify the most basic and core triggering and feedback functions of the thyristor level.

[0004] Current testing instruments and methods test each thyristor stage individually, but due to the large number of thyristor stages, the testing time is too long, consuming a lot of power outage maintenance time. This has become one of the main obstacles to further improving the energy utilization rate of DC systems, resulting in low maintenance and testing efficiency. Summary of the Invention

[0005] This invention provides a testing method and apparatus for thyristor converter valve assemblies, which solves the problem of low maintenance and testing efficiency in the prior art.

[0006] To solve the above-mentioned technical problems, the technical solutions included in this invention and their corresponding beneficial effects are as follows:

[0007] This invention provides a testing method for a thyristor converter valve assembly. A first electrode and a third electrode are set at both ends of the converter valve assembly under test, and a second electrode is set at the conductive connection between two thyristor stages in the middle. The test involves: simultaneously sending a conduction signal to the thyristor stage, inputting positive and negative voltages to the first and second electrodes, and the segment between the third and second electrodes; real-time monitoring of the current in the circuits of the first and second electrodes, and the third and second electrodes, to determine whether the converter valve assembly is conducting; if both positive and negative currents are detected in the corresponding circuits, the thyristor stage triggering function in the corresponding segment of the converter valve assembly is normal; if only positive current is detected in the circuit, a thyristor stage with abnormal reverse triggering function exists in the corresponding segment of the converter valve assembly; if only negative current is detected in the circuit, a thyristor stage with abnormal forward triggering function exists in the corresponding segment of the converter valve assembly.

[0008] The beneficial effects of the above technical solution are as follows: In existing converter valve assembly testing, each thyristor stage requires 220V of voltage; for a 15-stage converter valve assembly, this requires an input AC voltage of 3300V. In this invention, the circuit formed by the first and second electrodes is connected in parallel with the circuit formed by the second and third electrodes. AC voltage is input to the two parallel circuits to test the triggered thyristor stages, effectively halving the test voltage. This helps reduce the safety risks associated with high-voltage testing, decreases the design size and weight of the testing device, and enables component-level thyristor-level trigger function testing. This improves the overall trigger function testing efficiency of the converter valve several times, thereby enhancing the efficiency of converter valve maintenance and testing.

[0009] Furthermore, if an abnormal thyristor stage is found, the first electrode and the third motor are respectively set at both ends of the corresponding section of the converter valve assembly, and the second electrode is set at the conductive connection between two thyristor stages in the middle of the corresponding section; the test is performed again to gradually narrow the detection range until the abnormal thyristor stage is located.

[0010] When the converter valve assembly triggers a malfunction, the corresponding section of the converter valve assembly that has no current flowing in either the forward or reverse direction is reconstructed for testing. Each test can narrow down the range by half, ultimately identifying one or more thyristor stages that trigger the malfunction, thereby improving efficiency.

[0011] Furthermore, after sending a conduction signal to the thyristor stage, it is determined whether the valve control backend can receive all thyristor stage test messages, which is used to determine whether the return test function of the converter valve assembly is normal.

[0012] The valve control backend can also be used to simultaneously check the back-inspection function of the converter valve assembly. If an abnormality is found, the specific location information of the abnormality can be obtained from the valve control backend.

[0013] Furthermore, the MSC is used to send a turn-on signal to the thyristor stage.

[0014] The multiple thyristor stages in the converter valve assembly send conduction signals through the MSC and simultaneously output positive and negative voltages, resulting in better synchronization.

[0015] This invention also provides a test device for a thyristor converter valve assembly, comprising a first electrode, a second electrode, and a third electrode. The first and third electrodes are disposed at both ends of the converter valve assembly to be tested, and the second electrode is disposed at the conductive connection between two intermediate thyristor stages. Simultaneously with sending a conduction signal to the thyristor stage, positive and negative voltages are input to the first and second electrodes, and the segment between the third and second electrodes. The current in the circuits of the first and second electrodes, and the third and second electrodes, is detected in real time to determine whether the converter valve assembly is conducting. If both positive and negative currents are detected in the corresponding circuit, the thyristor stage triggering function in the corresponding segment of the converter valve assembly is normal. If only positive current is detected in the circuit, a thyristor stage with abnormal reverse triggering function exists in the corresponding segment of the converter valve assembly. If only negative current is detected in the circuit, a thyristor stage with abnormal positive triggering function exists in the corresponding segment of the converter valve assembly.

[0016] The beneficial effects of the above technical solution are as follows: In existing converter valve assembly testing, each thyristor stage requires 220V of voltage; for a 15-stage converter valve assembly, this requires an input AC voltage of 3300V. In this invention, the circuit formed by the first and second electrodes is connected in parallel with the circuit formed by the second and third electrodes. AC voltage is input to the two parallel circuits to test the triggered thyristor stages, effectively halving the test voltage. This helps reduce the safety risks associated with high-voltage testing, decreases the design size and weight of the testing device, and enables component-level thyristor-level trigger function testing. This improves the overall trigger function testing efficiency of the converter valve several times, thereby enhancing the efficiency of converter valve maintenance and testing.

[0017] Furthermore, it also includes a trigger fiber for sending a conduction signal to the thyristor stage via the converter valve device MSC.

[0018] The multiple thyristor stages in the converter valve assembly send conduction signals through the MSC and simultaneously output positive and negative voltages, resulting in better synchronization.

[0019] Furthermore, it also includes an insulating support, three metal ends, and an insulating nut; the insulating support has a sliding groove in the middle; the three metal ends serve as three electrodes respectively, and the metal ends are fixed in the sliding groove by fastening bolts that serve as insulating nuts. After adjusting the metal ends to the position of the heat sink corresponding to the condenser end of the converter valve assembly to be tested, the metal ends are fixed by tightening the fastening bolts. The test device is then placed on the converter valve assembly to be tested, so that the metal ends make conductive contact with the corresponding heat sink, and the test device's own weight ensures reliable conduction between the metal ends and the corresponding heat sink.

[0020] The device of the present invention uses an insulating support that is no shorter than the converter valve assembly under test as a base. Three metal ends are slidably fixed on the support as electrodes via a sliding groove. By adjusting the position of the three metal ends on the insulating support, accurate correspondence with the conductive parts at the beginning, end and middle of the corresponding section of the converter valve assembly under test can be easily achieved. In addition, the weight of the device itself can be used to ensure reliable contact between the three metal ends and the corresponding conductive parts, replacing manual fixing, avoiding direct contact between people and the testing device, and ensuring personal safety.

[0021] Furthermore, the insulating support has an insulating handle for hand use in the middle.

[0022] The insulated handle can be held directly and placed on the converter valve assembly under test for testing. The insulated handle is easy to handle. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the test method for a thyristor converter valve assembly (15-stage thyristor);

[0024] Figure 2(1) is a schematic diagram of the test method for the thyristor converter valve assembly (8-stage thyristor);

[0025] Figure 2(2) is a schematic diagram of the method for locating abnormal thyristor stages in a thyristor converter valve assembly (8-stage thyristor);

[0026] Figure 3 This is a simulation waveform diagram of the working principle of the component-level tester in the test device for thyristor converter valve components;

[0027] Figure 4(1) is a schematic diagram of the output connection device in the test device of the thyristor converter valve assembly;

[0028] Figure 4(2) is a schematic diagram of the insulating nut model in the output connection device of the test device for the thyristor converter valve assembly;

[0029] Figure 5(1) shows the test results of the thyristor converter valve assembly (8-stage thyristor) with positive and reverse current waveforms.

[0030] Figure 5(2) is a schematic diagram of the test results of the thyristor converter valve assembly (8-stage thyristor) with only the positive current waveform;

[0031] Figure 5(3) is a schematic diagram of the test results of the thyristor converter valve assembly (8-stage thyristor) with only the reverse current waveform. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0033] Method Implementation Examples:

[0034] like Figure 1 The test apparatus shown is applicable to the test method of the thyristor converter valve assembly of the present invention, including an assembly-level tester 1 and an output connection device.

[0035] The component-level tester includes a primary circuit, a detection circuit, and a control system. The primary circuit is used to output the required AC voltage. The detection circuit is used to detect the current on the output side of the primary circuit in real time to determine whether the thyristor is triggered. The control system mainly completes the voltage output control of the primary circuit, the sending of trigger signals, and the analysis and judgment of the detection results, and outputs the test results.

[0036] Specifically, such as Figure 3 As shown, the primary circuit converts the 220V AC input voltage into an AC voltage with the required number of cycles and voltage amplitude; the detection circuit converts the current waveform in the primary circuit into a voltage signal input to the control system; the control system realizes time control of the output voltage of the primary circuit, sends a trigger signal to the valve assembly under test at the appropriate time, and receives the output signal from the detection circuit and performs logical judgment.

[0037] The output connection device includes a connecting wire 21 and a connecting handle 22. The connecting wire 21 is used to connect the tester 1 and the connecting handle. The connecting wire 21 is a 3-core cable, which only branches out into wires at both ends. The tester end is designed with a banana plug for higher safety, and the connecting handle end is designed with an alligator clip for easy operation. Its length can be selected according to the height of the tower valve. The connecting handle includes an insulating support 221 and three metal ends 222, which are used to realize the quick connection between the wire 21 and the thyristor stage and the heat sinks 41 on both sides. The thyristor stage is composed of several thyristors 31, and each thyristor is equipped with a heat sink 41 on both sides. The tester is connected to the spare optical inlet of the multi-channel star coupler (MSC) of the component under test using a trigger fiber 5. If some converter valve equipment does not have an MSC design, a trigger signal can be sent to the thyristor stage through valve control settings without connecting this fiber, as shown in Figure 2.

[0038] As shown in Figure 4(1), an insulating handle 223 is provided in the middle of the connecting handle for hand placement, which can avoid the safety risks caused by misoperation; each contact can slide freely in the horizontal direction, and after positioning, the insulating nut 224 can be rotated to fix it, as shown in Figure 4(2).

[0039] The specific testing method is as follows:

[0040] (1) As Figure 1 As shown, place the tester on the ground or on a lifting platform, and correctly place the connecting handle on the component under test. For example, for a Class 15 component, place the metal contacts on both sides of the connecting handle on R1 and R16 of the component, and place the metal contact in the middle on R9 of the component. Use the connecting wire to correctly connect the tester body and the connecting handle.

[0041] (2) Set the background of the valve control system of the valve component under test to test monitoring mode to detect the report information of the thyristor.

[0042] (3) Connect the test instrument to the spare optical inlet of the multi-channel star coupler (MSC) of the component under test using a trigger fiber, such as... Figure 1 As shown in Figure 2, if some converter valve equipment does not have MSC design, a trigger signal can be sent to the thyristor stage through valve control settings without connecting to the optical fiber.

[0043] (4) Power on the tester and rotate the test button to output the AC test voltage with the required number of cycles and voltage amplitude.

[0044] (5) The tester detects the current waveform and amplitude, and displays the test results after logical judgment.

[0045] The MSC sends a turn-on signal to the thyristor stage and simultaneously inputs positive and negative voltages into the loop formed by the metal terminal on one side of the first electrode, the middle metal terminal on the second electrode, the metal terminal on the other side of the third electrode, and the middle metal terminal on the second electrode. The current in the loop of the first electrode and the second electrode, as well as the loop of the third electrode and the second electrode, is detected in real time to determine whether the converter valve assembly is turned on.

[0046] When the test results show that both the forward and reverse directions are passed, and the valve control backend can receive all thyristor-level test messages of the component, the test is passed, all thyristor-level triggering and back-checking functions are normal, and the current waveform is shown in Figure 5(1).

[0047] When the test results show that both the forward and reverse directions are passed, and one or more thyristor-level test messages cannot be received by the valve control backend, the test fails, and one or more thyristor-level backtest functions are abnormal. The specific location of the abnormality can be obtained from the valve control backend.

[0048] When the test results show that the forward test is passed and the reverse test is failed, and the valve control backend can receive all thyristor level test messages of the component, the test is failed and the triggering function of one or more thyristor levels in the reverse connection is abnormal. The current waveform is shown in Figure 5(2). The specific abnormal location information can be obtained by retesting the reverse-connected thyristor level with the component tester, gradually narrowing down the range, or by testing and judging with the thyristor level function tester.

[0049] When the test results show that the forward connection fails and the reverse connection passes, and the valve control backend can receive all thyristor level test messages of the component, the test fails and one or more thyristor levels in the forward connection trigger function is abnormal. The current waveform is shown in Figure 5(3). The specific abnormal location information can be obtained by retesting the thyristor level in the forward connection with the component tester, gradually narrowing down the range, or by testing and judging with the thyristor level function tester.

[0050] When the test results show that both the forward and reverse directions fail, and the valve control backend can receive all thyristor-level test messages for the component, the test fails. This indicates that one or more thyristor-level triggering functions are abnormal in both the forward and reverse directions, and no current flows through them.

[0051] When the test result shows that the forward or reverse direction fails, and one or more thyristor-level test messages cannot be received by the valve control backend, the test fails, the triggering function of one or more thyristors connected in the corresponding forward or reverse direction is abnormal, and the return check function of one or more thyristors is abnormal.

[0052] The following description, with reference to the accompanying drawings, uses the thyristor-level T6 trigger function malfunction (8-stage single-pulse valve assembly) as an example to further illustrate the specific implementation of the present invention.

[0053] During a forward connection:

[0054] Connect correctly according to the diagram in Figure 2(1); set the valve control backend to test mode, in a state where it can send trigger signals and detect return signals; start the test, the tester panel shows that the forward connection (T1~T4) passes, the reverse connection (T5~T8) fails, and all thyristor stages (T1~T8) in the backend can receive return information, indicating that T5~T8 has a thyristor stage trigger function fault, and its current waveform is shown in Figure 5(2); to clarify the specific fault location of T5~T8, adjust the position of the metal contacts and connect according to the diagram in Figure 2(2); test again, the tester panel shows that the forward connection (T5~T6) fails, the reverse connection (T7~T8) passes, indicating that T5~T6 has a thyristor stage trigger function fault; in this way, test T5 and T6 again to find the specific fault location.

[0055] The testing method based on this tester basically follows the conventional test setup method for a single thyristor level. It only requires pressurizing the entire valve assembly (valve section) and using the MSC spare optical port. There is no need to plug or unplug the inherent optical fiber of the valve assembly under test. The entire test procedure will not produce the risk of failure due to operational problems.

[0056] For converter valves, each component includes 7 to 15 thyristor stages. Traditional thyristor stage triggering tests require 7 to 15 tests to complete one component. However, the component-level tester described in this solution can complete one component test in just one test under normal circumstances. Even in abnormal conditions where a thyristor stage has a triggering function failure, the test of one component will not exceed 4 tests. Therefore, the component-level tester can improve the maintenance efficiency of this work by 5 to 10 times.

[0057] Device Example:

[0058] The hardware structure and specific implementation method of the test device for a thyristor converter valve assembly of the present invention have been described sufficiently clearly in the test method embodiments of the thyristor converter valve assembly, and will not be repeated here.

[0059] The specific embodiments of the present invention have been given above, but the present invention is not limited to the described embodiments. Under the concept given by the present invention, the technical means in the above embodiments can be changed, replaced, or modified in a way that is easy for those skilled in the art to conceive of, and the effect is basically the same as the corresponding technical means in the present invention, and the purpose of the invention is also basically the same. The technical solution formed in this way is a fine-tuning of the above embodiments, and such technical solution still falls within the protection scope of the present invention.

Claims

1. A test method for a thyristor converter valve assembly, characterized in that, A first electrode and a third electrode are set at both ends of the converter valve assembly under test, and a second electrode is set at the conductive connection between two thyristor stages in the middle, resulting in two parallel circuits. The first circuit consists of the first electrode, the second electrode, and the thyristor stage in the corresponding segment between the first electrode and the second electrode in the converter valve assembly under test; the second circuit consists of the second electrode, the third electrode, and the thyristor stage in the corresponding segment between the second electrode and the third electrode in the converter valve assembly under test. The method consists of the following steps: 1) While sending a turn-on signal to the thyristor stage, positive and negative AC voltages are input to both circuits; 2) The continuity of the converter valve assembly is determined by detecting the current in both circuits, and the test results are obtained; where: When both circuits pass, all thyristor-level triggering and feedback functions are normal; When both circuits pass, but one or more of the valve control backends cannot receive the thyristor-level test message, one or more thyristor-level backtest functions are abnormal. When the first circuit passes but the second circuit fails, the triggering function of one or more thyristors connected to the second circuit is abnormal. When the first circuit fails but the second circuit succeeds, the triggering function of one or more thyristors connected to the first circuit is abnormal. When both circuits fail, there is an abnormality in the triggering function of one or more thyristors connected to both circuits. When the first or second circuit fails, and one or more valve control backends cannot receive thyristor-level test messages, the triggering function of one or more thyristors connected in the corresponding first or second circuit is abnormal, and the return test function of one or more thyristors is abnormal.

2. The test method for the thyristor converter valve assembly according to claim 1, characterized in that, The first circuit and the second circuit are connected in parallel, and the number of thyristor stages in both parallel circuits is less than that in the entire converter valve assembly, so that the measured voltage is halved when the thyristor stages are triggered by the test of inputting positive and negative AC voltages to the two parallel circuits.

3. The test method for the thyristor converter valve assembly according to claim 1, characterized in that, After sending a conduction signal to the thyristor stage, it is determined whether the valve control backend can receive all thyristor stage test messages, which is used to determine whether the converter valve assembly backtest function is normal.

4. The test method for the thyristor converter valve assembly according to claim 1, characterized in that, The MSC is used to send a turn-on signal to the thyristor stage.

5. A testing device for a thyristor converter valve assembly, characterized in that, The device includes a first electrode, a second electrode, and a third electrode. The first and third electrodes are positioned at both ends of the converter valve assembly under test, and the second electrode is positioned at the conductive connection between two thyristor stages in the middle, forming two parallel circuits. The first circuit consists of the first electrode, the second electrode, and the corresponding thyristor stage between the first and second electrodes in the converter valve assembly under test. The second circuit consists of the second electrode, the third electrode, and the corresponding thyristor stage between the second and third electrodes in the converter valve assembly under test. While sending a conduction signal to the thyristor stage, positive and negative AC voltages are input to both circuits; the conduction status of the converter valve assembly is determined by detecting the current in the two circuits, and the test results are obtained; wherein: When both circuits pass, all thyristor-level triggering and feedback functions are normal; When both circuits pass, but one or more of the valve control backends cannot receive the thyristor-level test message, one or more thyristor-level backtest functions are abnormal. When the first circuit passes but the second circuit fails, the triggering function of one or more thyristors connected to the second circuit is abnormal. When the first circuit fails but the second circuit succeeds, the triggering function of one or more thyristors connected to the first circuit is abnormal. When both circuits fail, there is an abnormality in the triggering function of one or more thyristors connected to both circuits. When the first or second circuit fails, and one or more valve control backends cannot receive thyristor-level test messages, the triggering function of one or more thyristors connected in the corresponding first or second circuit is abnormal, and the return test function of one or more thyristors is abnormal.

6. The testing apparatus for the thyristor converter valve assembly according to claim 5, characterized in that, It also includes a trigger fiber for sending a conduction signal to the thyristor stage via the converter valve device MSC.

7. The testing apparatus for the thyristor converter valve assembly according to claim 5, characterized in that, It also includes an insulating support, three metal ends, and an insulating nut; the insulating support has a sliding groove in the middle; the three metal ends serve as three electrodes respectively, and the metal ends are fixed in the sliding groove by fastening bolts that serve as insulating nuts. After adjusting the metal ends to the position of the heat sink corresponding to the condenser end of the converter valve assembly to be tested, the metal ends are fixed by tightening the fastening bolts. The test device is then placed on the converter valve assembly to be tested, so that the metal ends make conductive contact with the corresponding heat sink, and the test device's own weight ensures reliable conduction between the metal ends and the corresponding heat sink.

8. The testing apparatus for the thyristor converter valve assembly according to claim 7, characterized in that, The insulating support has an insulating handle for hand use in the middle.

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