基于不平衡电压的磁控式并联电抗器控制绕组接地保护方案  

Protection scheme against control winding grounding fault of magnetically controlled shunt reactor based on unbalanced voltage

作　　者：郑涛[1] 韦俊琪 刘校销 李怀强 张健康 王康达 ZHENG Tao;WEI Junqi;LIU Xiaoxiao;LI Huaiqiang;ZHANG Jiankang;WANG Kangda(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China;Nothwest Electric Power Dispatching and Control Sub-Center,Xi’an 710048,China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,北京102206 [2]国家电网西北调控分中心,陕西西安710048

出　　处：《电力自动化设备》2021年第3期57-63,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51677069);国家电网公司科技项目(SGNW0000DKJS1900197)。

摘　　要：实际工程中对于特高压磁控式并联电抗器(MCSR)控制绕组接地故障配置直流母线过压保护,然而发生控制绕组端部接地故障时,母线极对地电压无交流过电压特征,导致保护无法识别该故障。针对该问题,分析了控制绕组接地故障及稳态运行、2种方式合闸、区外故障工况下母线极对地电压变化情况,基于此提出一种基于直流母线不平衡电压的控制绕组接地保护方案。该方案利用正、负极直流母线电压之和构造直流母线不平衡电压,基于故障下直流母线不平衡电压明显上升的特征识别故障。方案原理简单、易于实现,解决了现有保护无法识别控制绕组端部接地故障问题。在MATLAB/Simulink软件中搭建了750 kV三相MCSR仿真模型,大量仿真结果验证了该保护方案的有效性。In the actual project,the DC bus overvoltage protection is configured for the control winding grounding fault of the extra-high voltage MCSR(Magnetically Controlled Shunt Reactor).However,under the condition of grounding fault occurring in the end part of control winding,the DC bus does not exhibit AC overvoltage characteristic,which causes the protection to fail to identify the fault.To solve this problem,the characteristics of DC bus pole-to-ground voltage under different conditions,such as control winding grounding fault,steady-state operation,two ways of energizing and external faults,are analyzed.Based on this,a protection scheme based on DC bus unbalanced voltage is proposed,which uses the sum of the positive and negative DC bus voltages to construct an unbalanced voltage of DC bus,and identifies the fault based on the characteristic that the DC bus unbalanced voltage rises obviously during control winding grounding fault.The principle of the protection scheme is simple and easy to implement,which overcomes the problem that the conventional protection cannot identify the control winding end part grounding fault.A large number of simulative results based on MATLAB/Simulink verify the effectiveness of the proposed protection scheme.

关 键 词：磁控式并联电抗器 控制绕组 接地故障 直流母线 不平衡电压 控制绕组接地保护 

分 类 号：TM721[电气工程—电力系统及自动化] TM472[电气工程—电器]