基于双判据的特高压直流分层接入系统换相失败预防控制策略  

Commutation failure prevention control strategy based on double criteria for UHVDC hierarchical connection system

作　　者：王渝红[1] 陈立维 寇然 曾琦[1] 朱杰 WANG Yuhong;CHEN Liwei;KOU Ran;ZENG Qi;ZHU Jie(College of Electrical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学电气工程学院,四川成都610065

出　　处：《电力自动化设备》2022年第6期111-117,131,共8页Electric Power Automation Equipment

基　　金：国家电网公司总部科技项目(4000-202055048A-0-0-00)。

摘　　要：特高压直流分层接入系统中逆变侧受端交流系统故障可能造成高低端换流器同时发生换相失败。对此,综合考虑换流器发生换相失败的电压、电流因素,提出一种基于双判据的特高压直流分层接入系统换相失败预防控制策略。该策略基于换流母线电压变化特征,动态调整关断面积控制中关断角参考值;同时基于直流电流变化特征,得到换相电流面积控制中晶闸管触发角的修正量,进而优化选取各层换流器的触发角,预防高低端换流器同时发生换相失败。在PSCAD/EMTDC中搭建了仿真模型对不同工况下所提换相失败预防控制策略进行了验证。仿真结果表明,该策略能快速应对逆变侧交流系统故障,减小高低端换流器同时发生换相失败的风险,可预防分层接入系统高低端换流器同时发生换相失败。In UHVDC(Ultra-High Voltage Direct Current)hierarchical connection system,the fault of the receiving end AC system at inverter side may cause the commutation failure of the high terminal and low terminal converters simultaneously.In this regard,comprehensively considering the voltage and current factors of commutation failure of converters,a commutation failure prevention control strategy based on double criteria for UHVDC hierarchical connection system is proposed.This strategy is based on the changing characteristics of the commutation bus voltage and dynamically regulates the extinction angle reference in the extinction angle-time area control.At the same time,based on the changing characteristics of DC current,the correction value of the thyristor trigger angle in the current-time area control is obtained.Besides,the thyristor trigger angle of each layer is optimized,which can prevent the commutation failure of the high terminal and low terminal converters simultaneously.A simulation model is built in PSCAD/EMTDC to verify the proposed commutation failure prevention control strategy under different working conditions.The simulative results show that this strategy can quickly respond to inverter-side AC system faults,reduce the risk of simultaneous commutation failures of high terminal and low terminal converters and prevent the simultaneous commutation failure of high terminal and low terminal converters in the hierarchical connection system.

关 键 词：分层接入 换相失败 控制策略 特高压直流 关断面积 

分 类 号：TM721.1[电气工程—电力系统及自动化]