CN-121995271-A - Double-pole modular converter full-bridge submodule open-circuit fault positioning method and system

CN121995271ACN 121995271 ACN121995271 ACN 121995271ACN-121995271-A

Abstract

The invention discloses a method and a system for positioning an open circuit fault of full-bridge submodules of a bipolar modularized converter, wherein the method comprises the steps of collecting capacitance and voltage data of each full-bridge submodule on each bridge arm of the bipolar modularized converter; the method comprises the steps of calculating a capacitance voltage average value of each sub-module at each sampling moment, calculating the absolute error of the capacitance voltage of each sub-module at each sampling moment according to the capacitance voltage data and the average value, calculating the standard deviation of the capacitance voltage of each sub-module at each sampling moment, constructing a corresponding confidence threshold interval according to the capacitance voltage average value and a standard value, performing fault diagnosis and positioning, judging that a fault occurs when the capacitance voltage value of a certain sub-module at the sampling moment exceeds the confidence threshold interval and the time reaches the preset decision time, and outputting a positioning result. The method does not need an accurate mathematical model and additional hardware equipment, has simple and efficient algorithm, can effectively position and cut off the fault sub-module, and can improve the operation stability of the bipolar modular converter.

Inventors

ZHEN HONGNING
Han Zhigun
YANG BIN
DENG FUJIN
WANG XIANGJIE
Wu Bingdao
YI HAORAN
LI JINKE
GU KANGHUI
ZHANG RUIYONG
XU WENCHAO
FENG WEI
XU DAN
WU JINGYANG
Sun Shunxiang

Assignees

中国能源建设集团江苏省电力设计院有限公司

Dates

Publication Date: 20260508
Application Date: 20260120

Claims (10)

1. The full-bridge submodule open-circuit fault positioning method for the bipolar modular converter is characterized by comprising the following steps of: collecting capacitance and voltage data of each full-bridge submodule on each bridge arm of the bipolar modularized converter; calculating the average value of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data of each full-bridge sub-module on each bridge arm; calculating the absolute error of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data and the capacitance voltage average value; calculating the standard deviation of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the absolute error of the capacitance voltage; Constructing a corresponding confidence threshold interval according to the capacitance voltage average value and the capacitance voltage standard value, and carrying out fault diagnosis and positioning on the full-bridge submodule: When the capacitance voltage value of a certain full-bridge submodule at the sampling moment exceeds a confidence threshold value interval and the time reaches a preset decision time, judging that the full-bridge submodule fails, and outputting a corresponding positioning result.
2. The method of claim 1, wherein the bipolar modular converter comprises a bipolar transformer and a modular circuit, the bipolar transformer comprising a primary winding Primary and secondary windings Secondary winding two The primary winding And a secondary winding one By using Is connected with the secondary winding II By using Connection of secondary winding one The homonymous end of the three-phase upper bridge arm is connected with the secondary winding II Is connected with a three-phase lower bridge arm and a primary winding The homonymous terminal of the (E) is connected with a low-frequency side alternating current system; The modular circuit adopts a three-phase six-bridge arm structure, each phase comprises an upper bridge arm and a lower bridge arm, and each bridge arm consists of And the connection points of the upper bridge arm and the lower bridge arm are connected with the network side.
3. The method for locating an open circuit fault of a full-bridge submodule of a bipolar modular converter of claim 2 wherein said full-bridge submodule includes a capacitor Anti-parallel diode I Anti-parallel diode II Anti-parallel diode three Anti-parallel diode four The anti-parallel diode I Emitter and anti-parallel diode two The collector of the third anti-parallel diode is used as the output positive stage of the full-bridge submodule Transmitter and anti-parallel diode four of (2) Is connected to the collector of the (c) a, the output cathode is used as a full-bridge submodule; the anti-parallel diode I Emitter and anti-parallel diode three of (2) Collector and capacitor of (a) The positive end is connected with the second anti-parallel diode And anti-parallel diode four Emitter and capacitance of (a) The negative terminal is connected.
4. The method for locating an open circuit fault in a full bridge sub-module of a bipolar modular converter of claim 2, wherein said secondary winding one And secondary winding two The output voltage is inverted with equal amplitude.
5. The method for locating an open circuit fault of a full-bridge submodule of a bipolar modular converter of claim 1, wherein the capacitor voltage data is The capacitance-voltage average value calculation expression is: ; Wherein, the The average value of the capacitance voltage corresponding to the sampling moment; For the number of sub-modules in one leg, ; The absolute error of the capacitance voltage is obtained by calculating capacitance voltage data and capacitance voltage average value, and the expression is: 。
6. the method for locating an open circuit fault of a full-bridge submodule of a bipolar modular converter of claim 1, wherein the standard deviation of the capacitor voltage The expression is: ; Wherein, the For the number of sub-modules in one leg, ; Is the absolute error of the capacitor voltage.
7. The method for locating an open circuit fault of a full-bridge submodule of a bipolar modular converter according to claim 1, wherein the confidence threshold interval is constructed according to a capacitance-voltage average value and a standard deviation, and the expression is: ; Wherein, the The average value of the capacitance voltage corresponding to the sampling moment; Is the standard deviation of the capacitance voltage.
8. A full-bridge submodule open-circuit fault positioning system for a bipolar modular converter, comprising: the data acquisition module is used for acquiring capacitance and voltage data of each full-bridge submodule on each bridge arm of the bipolar modularized converter; The average value calculation module is used for calculating the average value of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data of each full-bridge sub-module on each bridge arm; The absolute error calculation module is used for calculating the absolute error of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data and the capacitance voltage average value; The standard deviation calculation module is used for calculating the standard deviation of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the absolute error of the capacitance voltage; the submodule fault positioning module is used for constructing a corresponding confidence threshold interval according to the capacitance voltage average value and the capacitance voltage standard value and carrying out fault diagnosis and positioning on the full-bridge submodule: When the capacitance voltage value of a certain full-bridge submodule at the sampling moment exceeds a confidence threshold value interval and the time reaches a preset decision time, judging that the full-bridge submodule fails, and outputting a corresponding positioning result.
9. A computer readable storage medium having stored thereon a computer program/instruction, which when executed by a processor, implements the steps of the bipolar modular converter full-bridge sub-module open fault localization method of any of claims 1 to 7.
10. A computer apparatus/device/system comprising: a memory for storing computer programs/instructions; A processor for executing the computer program/instructions to implement the steps of the bipolar modular converter full-bridge sub-module open fault localization method of any one of claims 1 to 7.

Description

Double-pole modular converter full-bridge submodule open-circuit fault positioning method and system Technical Field The invention relates to a method and a system for positioning an open circuit fault of a full-bridge submodule of a bipolar modularized converter, and belongs to the field of fault positioning of power electronic equipment. Background As the scale of renewable energy utilization continues to increase, low frequency ac transmission has become a powerful candidate for high voltage long distance power transmission. The bipolar modularized AC-AC converter is widely applied to the system due to the characteristics of simple structure and independent control of active power and reactive power. However, the converter includes a large number of full-bridge sub-modules, and the switching devices therein are prone to open-circuit faults, resulting in output waveform distortion, continuous rising of capacitor voltage, and the like. Therefore, an efficient positioning method specifically aiming at the problem is urgently needed. Disclosure of Invention The invention aims to provide a method and a system for positioning open faults of full-bridge submodules of a bipolar modular converter, which are used for synchronously collecting capacitance voltage data of all submodules in the same bridge arm, calculating the average value, absolute error and standard deviation of capacitance voltage of each submodule, constructing a confidence threshold value interval of capacitance voltage of the submodule, and judging and accurately positioning faults of the submodule according to whether the voltage value exceeds the interval and reaches preset time. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme. In a first aspect, the present invention provides a method for locating an open circuit fault of a full-bridge submodule of a bipolar modular converter, including: collecting capacitance and voltage data of each full-bridge submodule on each bridge arm of the bipolar modularized converter; calculating the average value of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data of each full-bridge sub-module on each bridge arm; calculating the absolute error of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the capacitance voltage data and the capacitance voltage average value; calculating the standard deviation of the capacitance voltage of each full-bridge sub-module at each sampling moment according to the absolute error of the capacitance voltage; Constructing a corresponding confidence threshold interval according to the capacitance voltage average value and the capacitance voltage standard value, and carrying out fault diagnosis and positioning on the full-bridge submodule: When the capacitance voltage value of a certain full-bridge submodule at the sampling moment exceeds a confidence threshold value interval and the time reaches a preset decision time, judging that the full-bridge submodule fails, and outputting a corresponding positioning result. Further, the bipolar modular converter comprises a bipolar transformer comprising a primary winding and a modular circuitPrimary and secondary windingsSecondary winding twoThe primary windingAnd a secondary winding oneBy usingIs connected with the secondary winding IIBy usingConnection of secondary winding oneThe homonymous end of the three-phase upper bridge arm is connected with the secondary winding IIIs connected with a three-phase lower bridge arm and a primary windingThe homonymous terminal of the (E) is connected with a low-frequency side alternating current system; The modular circuit adopts a three-phase six-bridge arm structure, each phase comprises an upper bridge arm and a lower bridge arm, and each bridge arm consists of And the connection points of the upper bridge arm and the lower bridge arm are connected with the network side. Further, the full-bridge submodule comprises a capacitorAnti-parallel diode IAnti-parallel diode IIAnti-parallel diode threeAnti-parallel diode fourThe anti-parallel diode IEmitter and anti-parallel diode twoThe collector of the third anti-parallel diode is used as the output positive stage of the full-bridge submoduleTransmitter and anti-parallel diode four of (2)Is connected to the collector of the (c) a, the output cathode is used as a full-bridge submodule; the anti-parallel diode I Emitter and anti-parallel diode three of (2)Collector and capacitor of (a)The positive end is connected with the second anti-parallel diodeAnd anti-parallel diode fourEmitter and capacitance of (a)The negative terminal is connected. Further, the secondary winding is oneAnd secondary winding twoThe output voltage is inverted with equal amplitude. Further, the fault location of the full-bridge submodule refers to an open circuit fault of one to four anti-parallel diodes of one full-