CN-120908656-B - Reliability test method and device for bypass switch of soft direct current converter valve submodule

CN120908656BCN 120908656 BCN120908656 BCN 120908656BCN-120908656-B

Abstract

The invention discloses a reliability test method and a device for a bypass switch of a soft direct current converter valve submodule, and relates to the technical field of soft direct current transmission, wherein the method comprises the steps of constructing a test loop of the bypass switch based on the working condition of the soft direct current converter valve submodule at an overvoltage fault point, wherein the test loop comprises a first precharge loop and an isolating switch thereof, a first capacitor and a discharging resistor thereof, an IGBT (insulated gate bipolar transistor), a diode, a second precharge loop and an isolating switch thereof, a second capacitor and a discharging resistor thereof, a hollow reactor and a bypass switch; the method comprises the steps of pre-charging a capacitor, switching on an IGBT, switching off the IGBT when the voltage of a first capacitor is smaller than the end discharge voltage, and switching on a bypass switch when the voltage of a second capacitor is larger than the voltage of a fault point, so that waveform data of voltage and current of each element in the test process are obtained and analyzed, and a reliability test result of the bypass switch is obtained. The invention solves the problem of lower accuracy of the existing test scheme and improves the accuracy of the bypass switch reliability test.

Inventors

GAO SHILONG
SONG JIAJIE
LIANG FUPING
XIAO BIJIAN
YANG YONG
ZHANG TAO
YU QIONG
WEN JUN
YI RONG
WANG GANG
WANG JIALONG
LI QI

Assignees

国网经济技术研究院有限公司
荣信汇科电气股份有限公司

Dates

Publication Date: 20260505
Application Date: 20250827

Claims (6)

1. A reliability test method for a bypass switch of a soft direct current converter valve submodule is characterized by comprising the following steps: The test circuit comprises a first pre-charge circuit, a first isolating switch, a first capacitor, a first discharging resistor, an insulated gate bipolar transistor IGBT, a diode, a second pre-charge circuit, a second isolating switch, a second capacitor, a second discharging resistor, an air-core reactor and a bypass switch; precharging the first capacitor and the second capacitor; Turning on the insulated gate bipolar transistor IGBT until the voltage of the first capacitor is smaller than a preset termination discharge voltage, and turning off the insulated gate bipolar transistor IGBT; when the voltage of the second capacitor is larger than the preset fault point voltage, closing the bypass switch; When the discharge of the test loop is monitored, waveform data of voltage and current of each element in the test loop in the test process are obtained, and the waveform data are analyzed to obtain a reliability test result of the bypass switch; Wherein, the test loop specifically includes: the first precharge loop is connected with the first capacitor through the first isolating switch and is used for precharging the first capacitor; the first capacitor is connected with the first discharge resistor in parallel; the second precharge circuit is connected with the second capacitor through the second isolating switch and is used for precharging the second capacitor; the second capacitor is connected with the second discharge resistor in parallel; The insulated gate bipolar transistor IGBT comprises a first capacitor, a second capacitor, a hollow reactor, a bypass switch, a bypass reactor, a first capacitor, a second capacitor, a bypass switch and a bypass reactor, wherein the collector of the insulated gate bipolar transistor IGBT is connected with the first capacitor, and the emitter of the insulated gate bipolar transistor IGBT is connected with the cathode of the diode; The utility model discloses a soft direct current converter valve submodule, including: According to the preset fault point voltage and current, calculating or simulating a preset test loop to obtain basic electrical parameters of each element in the test loop, initial voltage and initial current of each element, action time points or action thresholds of the insulated gate bipolar transistor IGBT and the bypass switch, and constructing the test loop of the bypass switch.
2. The method of reliability testing of a soft dc converter valve submodule bypass switch of claim 1, wherein said pre-charging said first capacitor and said second capacitor includes: closing the first isolation switch to enable the first precharge circuit to charge the first capacitor; when the voltage of the first capacitor is larger than a preset initial voltage, the first isolating switch is disconnected; closing the second isolation switch to cause the second precharge circuit to charge the second capacitor; and when the voltage of the second capacitor is larger than the preset initial voltage, the second isolating switch is disconnected.
3. The reliability test method of a soft direct current converter valve submodule bypass switch according to claim 1, wherein the insulated gate bipolar transistor IGBT has the capability of turning off at any current point in a preset discharge situation of the first capacitor, and the static withstand voltage level of the insulated gate bipolar transistor IGBT is greater than the maximum voltage across the insulated gate bipolar transistor IGBT during the test.
4. A reliability test device of a soft direct current converter valve submodule bypass switch is characterized by comprising: The test loop construction module is used for constructing a test loop of the bypass switch based on the working condition of the soft direct current converter valve submodule at an overvoltage fault point, wherein the test loop comprises a first precharge loop, a first isolating switch, a first capacitor, a first discharge resistor, an insulated gate bipolar transistor IGBT, a diode, a second precharge loop, a second isolating switch, a second capacitor, a second discharge resistor, an air-core reactor and a bypass switch; A capacitor precharge module for precharging the first capacitor and the second capacitor; The capacitor discharging module is used for switching on the insulated gate bipolar transistor IGBT until the voltage of the first capacitor is smaller than a preset termination discharging voltage, and switching off the insulated gate bipolar transistor IGBT; the bypass switch action module is used for closing the bypass switch when the voltage of the second capacitor is larger than the preset fault point voltage; The test result analysis module is used for obtaining waveform data of voltage and current of each element in the test loop in the test process when the test loop is completely discharged, and analyzing the waveform data to obtain a reliability test result of the bypass switch; Wherein, the test loop specifically includes: the first precharge loop is connected with the first capacitor through the first isolating switch and is used for precharging the first capacitor; the first capacitor is connected with the first discharge resistor in parallel; the second precharge circuit is connected with the second capacitor through the second isolating switch and is used for precharging the second capacitor; the second capacitor is connected with the second discharge resistor in parallel; The insulated gate bipolar transistor IGBT comprises a first capacitor, a second capacitor, a hollow reactor, a bypass switch, a bypass reactor, a first capacitor, a second capacitor, a bypass switch and a bypass reactor, wherein the collector of the insulated gate bipolar transistor IGBT is connected with the first capacitor, and the emitter of the insulated gate bipolar transistor IGBT is connected with the cathode of the diode; The test loop building module is specifically used for: According to the preset fault point voltage and current, calculating or simulating a preset test loop to obtain basic electrical parameters of each element in the test loop, initial voltage and initial current of each element, action time points or action thresholds of the insulated gate bipolar transistor IGBT and the bypass switch, and constructing the test loop of the bypass switch.
5. The device for testing the reliability of a bypass switch of a soft direct current converter valve submodule according to claim 4, wherein the capacitor precharge module is specifically configured to: closing the first isolation switch to enable the first precharge circuit to charge the first capacitor; when the voltage of the first capacitor is larger than a preset initial voltage, the first isolating switch is disconnected; closing the second isolation switch to cause the second precharge circuit to charge the second capacitor; and when the voltage of the second capacitor is larger than the preset initial voltage, the second isolating switch is disconnected.
6. The reliability test device of a soft direct current converter valve submodule bypass switch according to claim 4, wherein the insulated gate bipolar transistor IGBT has a capability of turning off at any current point in a preset discharge situation of the first capacitor, and a static withstand voltage level of the insulated gate bipolar transistor IGBT is greater than a maximum voltage across the insulated gate bipolar transistor IGBT during the test.

Description

Reliability test method and device for bypass switch of soft direct current converter valve submodule Technical Field The invention relates to the technical field of flexible direct current transmission, in particular to a reliability test method and device for a bypass switch of a flexible direct current converter valve submodule. Background The flexible high-voltage direct-current transmission adopts a converter valve of MMC (Modular Multilevel Converter, modularized multi-level converter) topology to realize high-quality and high-flexibility electric energy conversion between high-voltage alternating current and high-voltage direct current, and plays a key role in novel power system applications such as ultra-long-distance transmission of clean energy, interconnection of an asynchronous power grid, flexible multi-terminal interconnection, external transmission of deep-open sea new energy and the like. The extra-high voltage soft direct current converter valve is positioned in an extra-high voltage direct current circuit, extremely high reliability and availability are required, and the circuit is usually not allowed to stop running due to tripping of the converter valve caused by single fault. The MMC Sub-modules (Sub-modules, SMs) are the minimum functional units of the MMC topology, which may cause Sub-module overvoltage in case of failure or failure mode caused by partly unknown reasons, causing further risk for stable operation of the converter valve. The bypass switch is used as a key primary protection under the overvoltage fault mode of the submodule, and needs to reliably act when faults occur, so that the extra-high voltage soft direct current converter valve can continuously run under the faults of the single submodule and is not tripped. If the sub-module is in fault, the bypass switch is triggered in time, so that the fault point can be bypassed and the influence of the fault is limited to the fault module. Because the bypass switch is in a brake-separating maintaining state for a long time in the operation process of the converter valve, a trigger loop for triggering the bypass switch is also in an unactuated state for a long time, and potential functional fault points of the bypass switch are not easy to find. There is a need to fully verify the ability of the bypass switch to reliably operate before the converter valve is put into operation. However, prior art bypass switch reliability test schemes typically do not have associated fault simulation conditions, resulting in lower accuracy. Disclosure of Invention In order to solve the technical problems, the invention provides the reliability test method and the device for the bypass switch of the soft direct current converter valve submodule, which can accurately simulate the working condition of the primary protection bypass switch when the ultrahigh voltage soft direct current converter valve submodule fails in overvoltage, and improve the accuracy of the reliability test of the bypass switch. The embodiment of the invention provides a reliability test method of a bypass switch of a soft direct current converter valve submodule, which comprises the steps of constructing a test loop of the bypass switch based on the working condition of the soft direct current converter valve submodule at an overvoltage fault point, wherein the test loop comprises a first precharge loop, a first isolating switch, a first capacitor, a first discharge resistor, an IGBT (Insulate-Gate Bipolar Transistor, an insulated gate bipolar transistor), a diode, a second precharge loop, a second isolating switch, a second capacitor, a second discharge resistor, an air-core reactor and the bypass switch; precharging the first capacitor and the second capacitor; Switching on the IGBT until the voltage of the first capacitor is smaller than a preset termination discharge voltage, and switching off the IGBT; When the test loop discharge is monitored, waveform data of voltage and current of each element in the test loop in the test process are obtained, and the waveform data are analyzed to obtain a reliability test result of the bypass switch. As an improvement of the above scheme, the test circuit specifically includes: the first precharge loop is connected with the first capacitor through the first isolating switch and is used for precharging the first capacitor; the first capacitor is connected with the first discharge resistor in parallel; the second precharge circuit is connected with the second capacitor through the second isolating switch and is used for precharging the second capacitor; the second capacitor is connected with the second discharge resistor in parallel; the IGBT comprises a first capacitor, a second capacitor, an air-core reactor, a bypass switch, an air-core reactor and an air-core reactor, wherein the first capacitor is connected with the collector of the IGBT, the emitter of the IGBT is connected with the cathode of the diode, one end of the second