A batch detection method for bypass switches of flexible DC converter valve submodules

Abstract

The invention discloses a batch detection method for submodule bypass switches of a flexible direct current converter valve, comprising steps S1 to S3; the method of the invention automatically performs a batch closing test of all submodule bypass switches after direct current locking and when the residual voltage of the submodule capacitor meets the working voltage of a control board according to the characteristics of a voltage source power device of a flexible direct current converter valve of a flexible direct current transmission project, so as to detect whether the protective closing function of the submodule bypass switch is intact; when each submodule control board detects that the submodule capacitor voltage reaches a test voltage U2, a closing test is performed on each submodule bypass switch through a preset batch test command, and the closing status of each submodule bypass switch is returned to a background human-machine interface and displayed through an indicator light for confirmation by a tester, and when the closing status of the bypass switch is abnormal, an alarm message is used to prompt the tester for subsequent inspection and processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible direct current transmission converter valve submodule bypass switch closing function detection, and in particular relates to a flexible direct current converter valve submodule bypass switch batch detection method. Background Art

[0002] The existing method for detecting the opening and closing functions of the bypass switch of the submodule of the flexible DC converter valve is as follows: after the flexible DC converter valve is powered off, a submodule tester is used to apply working voltage to a single submodule, and then a submodule failure is simulated to trigger the submodule protection function to close the bypass switch for bypass switch closing function detection.

[0003] There are thousands of flexible direct current converter valve submodules in existing ultra-high voltage flexible direct current transmission projects. Each submodule is equipped with a bypass switch that closes in the event of a submodule failure to remove the bypass from the converter valve. The protective closing of the bypass switch requires the protection action signal of the submodule control board to be triggered. Therefore, the bypass switch closing function test requires at least the working voltage of the control board to be applied to the submodule before the closing trigger can be performed. The current method of using a submodule tester to test the closing function of a single submodule bypass switch first requires the use of a lift to lift the tester and the submodule tester to a height of more than 5 meters. The tester connects the submodule to the test line and uses the submodule tester to trigger the submodule protection to perform the bypass switch protective closing to test whether the bypass switch closing function is normal. This testing method consumes a lot of time and manpower. It takes more than 20 minutes to complete the test of a single submodule bypass switch. For thousands of submodules, it is impossible to complete all the tests during a power outage. It is impossible to effectively ensure that the closing function of all submodule bypass switches is effective in the event of a fault, thereby reliably removing the faulty module. Frequent and high-intensity aerial operations increase the risk of personal injury.

[0004] To this end, we propose a batch detection method for bypass switches of flexible DC converter valve submodules to solve the problems existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a batch detection method for sub-module bypass switches of a flexible DC converter valve. According to the characteristics of the voltage source power device of the flexible DC converter valve of the flexible DC transmission project, the present application automatically performs a batch closing test of all sub-module bypass switches after DC locking when the residual voltage of the sub-module capacitor meets the working voltage of the control board card, and detects whether the protective closing function of the sub-module bypass switch is intact, so as to solve the problems in the prior art raised in the above background technology.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A batch detection method for bypass switches of flexible DC converter valve submodules comprises the following steps:

[0008] Step S1, the flexible DC converter valve is a voltage source type power device, and each submodule is equipped with an energy storage capacitor. When the converter valve is operating normally, the capacitor voltage is stabilized at the rated voltage Un of several thousand volts. The control board inside the submodule obtains energy through the energy storage capacitor, converts the capacitor working voltage to a smaller working voltage U to drive the control board to work, and realizes the control of the submodule working state and protection action function; in the process of the submodule capacitor voltage dropping from the rated voltage to the submodule control board working voltage, the submodule control board is still in a working state and can normally receive the control command of the upper valve control system and send it to each submodule component for execution. In this process, the valve control system presets the submodule bypass switch protective closing function batch test command to realize the batch test of the bypass switch;

[0009] Step S2, before the flexible direct current converter valve is powered off, the bypass switch batch test is manually performed through the "power off and bypass switch batch test one-key sequential control" function when the submodule residual voltage meets the submodule control board working voltage and meets the bypass switch test conditions: the submodule range that needs to be batch tested is selected according to the area division, and the preset test batch test command is sent to each submodule control board to be tested. When the submodule control board detects that the capacitor voltage drops to the preset test voltage U2, the submodule control board issues a bypass switch closing command to close the bypass switch;

[0010] Step S3, the closing status of the bypass switch of the submodule is returned to the background human-machine interface for display to facilitate the test personnel to confirm. When the closing status of the bypass switch is abnormal, the test personnel is prompted for subsequent inspection and processing.

[0011] Preferably, in step S1, after the working state of the submodule and the protection action function are controlled, it can be ensured that the minimum capacitor voltage for the control board to obtain the normal working voltage is U1.

[0012] Preferably, when the converter valve is locked, the electric energy in the energy storage capacitor will be slowly released through the resistor to reduce the voltage from Un to 0.

[0013] Preferably, in step S2, a preset test batch test command for a submodule range that needs batch testing is sent to each submodule to be tested, and the control board card is divided into a valve hall or a valve layer.

[0014] Preferably, in step S2, when the submodule control board detects that the capacitor voltage drops to a preset test voltage U2, U1 <U2<Un。

[0015] Preferably, in step S3, the closing status of the bypass switch of the submodule is returned to the background human-machine interface for display so that the tester can confirm that the display method adopted is an indicator light;

[0016] When the closing condition of the bypass switch is abnormal, the tester is prompted for subsequent inspection and handling. The prompting method adopted is an alarm message.

[0017] Technical effects and advantages of the present invention: A batch detection method for bypass switches of flexible DC converter valve sub-modules proposed by the present invention has the following advantages compared with the prior art:

[0018] 1. Principle of realizing batch testing of protective closing of bypass switches of flexible DC converter valve sub-modules: The flexible DC converter valve is a voltage-source type power device, and each sub-module is configured with an energy storage capacitor. When the converter valve operates normally, the capacitor voltage is stable at the rated voltage Un of several thousand volts. The control board inside the sub-module obtains energy from the energy storage capacitor, converts the capacitor operating voltage to a smaller operating voltage to drive the control board to work, and the sub-module control board realizes the control of the sub-module working state and protection action function. The minimum capacitor voltage that can ensure the control board obtains the normal working voltage is U1. When the capacitor voltage of the sub-module is at the preset test voltage U2 (U1 < U2 < Un), the closing tests of the bypass switches of each sub-module are carried out through the preset batch test command.

[0019] 2. Method for batch testing of protective closing of bypass switches of flexible DC converter valve sub-modules: ① Use the "one-key sequence control for power outage and batch testing of bypass switches" function to pre-select the range of sub-modules that need to be batch-tested according to the valve hall or valve layer area. ② Use the "one-key sequence control for power outage and batch testing of bypass switches" function to control the flexible DC converter valve group control system CCP to send signals of power outage and the selected range of sub-modules that need to be batch-tested to the valve control. ③ When each sub-module control board detects that the capacitor voltage of the sub-module reaches the test voltage U2, the closing tests of the bypass switches of each sub-module are carried out through the preset batch test command. ④ The closing conditions of each sub-module bypass switch are returned to the background man-machine interface and displayed through indicator lights for the tester to confirm. When the closing condition of the bypass switch is abnormal, the tester is prompted by means of an alarm message for subsequent inspection and handling.

[0020] Other features and advantages of the present invention will be described in the subsequent description, and some will be obvious from the description or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the description and the drawings. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the topology structure of the flexible DC converter valve in the embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the topology structure of the flexible DC converter valve sub-module in the embodiment of the present invention. Detailed Embodiment

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0024] The present invention provides an embodiment as follows: Figure 1-2 as shown:

[0025] A method for batch testing bypass switches of flexible DC converter valve sub-modules includes the following steps:

[0026] Step S1: The flexible DC converter valve is a voltage-source power device, and each sub-module is configured with an energy storage capacitor. When the converter valve operates normally, the capacitor voltage is stable at the rated voltage Un of several thousand volts. The control board inside the sub-module obtains energy through the energy storage capacitor, converts the capacitor working voltage to a smaller working voltage U to drive the control board to work, and realizes the control of the working state and protection action function of the sub-module. The minimum capacitor voltage that can ensure the control board obtains the normal working voltage is U1. When the converter valve is blocked, the electrical energy in the energy storage capacitor will be slowly released through a resistor to reduce the voltage from Un to 0. During the process of the sub-module capacitor voltage dropping from the rated voltage to the working voltage of the sub-module control board, the sub-module control board is still in the working state and can normally receive the control commands from the upper-level valve control system and send them to each component of the sub-module for execution. During this process, batch test commands for the protective closing function of the sub-module bypass switch are preset through the valve control system to realize the batch testing of the bypass switch;

[0027] Step S2: Before the flexible DC converter valve is powered off, manually operate to perform batch testing of the bypass switch through the "one-key sequence control for power-off and batch testing of bypass switches" function when the residual voltage of the sub-module meets the condition for testing the bypass switch with the working voltage of the sub-module control board: Select the range of sub-modules to be batch-tested according to the valve hall or valve layer area, preset the batch test command, and send it to the control boards of each sub-module to be tested. When the sub-module control board detects that the capacitor voltage drops to the preset test voltage U2 (U1 < U2 < Un), the sub-module control board issues a bypass switch closing command to close the bypass switch;

[0028] Step S3: The closing situation of the sub-module bypass switch is returned to the background human-machine interface and displayed through an indicator light for the tester to confirm. When the closing situation of the bypass switch is abnormal, the tester is prompted through an alarm message for subsequent inspection and processing.

[0029] In summary, the implementation principle of the batch test for the protective closing of the bypass switch of the flexible DC converter valve sub-module: The flexible DC converter valve is a voltage-source power device, and each sub-module is equipped with an energy storage capacitor. When the converter valve operates normally, the capacitor voltage is stabilized at the rated voltage Un of several thousand volts. The control board inside the sub-module obtains power from the energy storage capacitor and converts the capacitor operating voltage to a smaller operating voltage to drive the control board to work. The sub-module control board realizes the control of the working state and protection action function of the sub-module. The minimum capacitor voltage that can ensure the control board obtains the normal working voltage is U1. When the capacitor voltage of the sub-module is at the preset test voltage U2 (U1 < U2 < Un), the closing test of the bypass switch of each sub-module is carried out through the preset batch test command.

[0030] Batch test method for the protective closing of the bypass switch of the flexible DC converter valve sub-module: ① Use the "one-key sequence control for power outage and batch test of bypass switches" function to pre-select the range of sub-modules that need to be batch-tested according to the valve hall or valve layer area. ② Use the "one-key sequence control for power outage and batch test of bypass switches" function to control the converter valve group control system CCP of the flexible DC converter valve to send a power outage and the signal of the selected range of sub-modules that need to be batch-tested to the valve control. ③ When each sub-module control board detects that the capacitor voltage of the sub-module reaches the test voltage U2, the closing test of the bypass switch of each sub-module is carried out through the preset batch test command. ④ The closing status of each sub-module bypass switch is returned to the background human-machine interface and displayed through indicator lights for the testers to confirm. When the closing status of the bypass switch is abnormal, the tester is prompted through alarm messages for subsequent inspection and handling.

[0031] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacement of some technical features. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A batch detection method for bypass switches of flexible DC converter valve submodules, characterized in that: The steps include: Step S1, the flexible DC converter valve is a voltage source type power device, and each submodule is equipped with an energy storage capacitor. When the converter valve is operating normally, the capacitor voltage is stabilized at the rated voltage Un of several thousand volts. The control board inside the submodule obtains energy through the energy storage capacitor, converts the capacitor working voltage to a smaller working voltage U to drive the control board to work, and realizes the control of the submodule working state and protection action function; in the process of the submodule capacitor voltage dropping from the rated voltage to the submodule control board working voltage, the submodule control board is still in a working state and can normally receive the control command of the upper valve control system and send it to each submodule component for execution. In this process, the valve control system presets the submodule bypass switch protective closing function batch test command to realize the batch test of the bypass switch; Step S2, before the flexible DC converter valve is powered off, the bypass switch batch test is manually performed through the "power off and bypass switch batch test one-key sequential control" function when the submodule residual voltage meets the submodule control board working voltage and meets the bypass switch test conditions: the submodule range that needs to be batch tested is selected according to the area division, and the preset test batch test command is sent to each submodule control board to be tested. When the submodule control board detects that the capacitor voltage drops to the preset test voltage U2, the submodule control board issues a bypass switch closing command to close the bypass switch; Step S3, the closing status of the bypass switch of the submodule is returned to the background human-machine interface for display to facilitate the test personnel to confirm. When the closing status of the bypass switch is abnormal, the test personnel is prompted for subsequent inspection and processing.

2. A batch detection method for bypass switches of flexible DC converter valve submodules according to claim 1, characterized in that: In step S1, after the working state and protection action function of the submodule are controlled, the minimum capacitor voltage that can ensure that the control board obtains the normal working voltage is U1.

3. A batch detection method for bypass switches of flexible DC converter valve submodules according to claim 2, characterized in that: When the converter valve is closed, the electric energy in the energy storage capacitor will be slowly released through the resistor to reduce the voltage from Un to 0.

4. A method for batch detection of bypass switches of flexible DC converter valve submodules according to claim 1, characterized in that: In step S2, a batch test command is sent to each submodule to be tested, and the control board is divided into valve halls or valve layers.

5. The method for batch detection of bypass switches of flexible DC converter valve submodules according to claim 1 is characterized in that: In step S2, when the submodule control board detects that the capacitor voltage drops to the preset test voltage U2, U1 <U2<Un。 6. A batch detection method for bypass switches of flexible DC converter valve submodules according to claim 1, characterized in that: In step S3, the closing status of the bypass switch of the submodule is returned to the background human-machine interface for display so that the tester can confirm that the display method adopted is the indicator light; When the bypass switch closing condition is abnormal, the test personnel will be prompted for subsequent inspection and processing, and the prompt method adopted is an alarm message.

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