电容换相换流器直流输电系统稳态及暂态特性  

Steady-State and Transient Characteristics of CCC-HVDC Transmission System

作　　者：刘耀[1] 谢晨曦[2] 王华伟[1] 李新年[1] 

机构地区：[1]中国电力科学研究院,北京市100192 [2]北京市电力公司海淀供电局,北京市100086

出　　处：《电力建设》2014年第7期86-91,共6页Electric Power Construction

基　　金：国家电网公司科技项目(XT17201200065)

摘　　要：电容换相换流器(capacitor commutated converter,CCC)是通过对传统直流输电系统主回路结构进行改造,串入适当的电容,补偿换流器吸收的无功功率,使得实际的换相电压在幅值和相位上发生变化,从而减少了换流器无功功率的吸收,降低了逆变侧发生换相失败的概率,提高了直流系统运行的稳定性。但是,在拥有上述优点的同时,CCC直流系统也有其固有的缺陷,为此首先对整流侧、逆变侧基于CCC的高压直流输电系统机理、稳态特性进行了研究,并基于电磁暂态仿真软件(PSCAD)建立的模型进行了仿真验证,将结果与传统直流输电系统进行了对比;重点分析了CCC直流输电系统抵御换相失败特性、逆变侧单相短路故障后的恢复特性和持续故障机理,研究了串联电容大小对恢复过程的影响。研究结果对于进一步优化CCC直流输电系统的动态特性及推广CCC直流输电技术具有重要意义。Capacitor commutated converter （ CCC ） can compensate reactive power absorbed by converter through the transformation of the main circuit structure in traditional DC transmission system with appropriate capacitor, which can make the amplitude and phase of actual commutation voltage change, reduce the reactive power absorption by converter and the probability of commutation failure of the inverter-side, so as to improve the stability of DC system. However, with the above advantages, CCC DC system also has inherent defects. This paper firstly studied the mechanism and steady-state characteristics of HVDC transmission system whose rectifier side and inverter side were based CCC. The model was built with using PSCAD, and verified by simulation, whose results were compared with traditional DC transmission system. Secondly, this paper specially analyzed the characteristics of avoiding commutation failure, the recovery characteristics after a short single-phase fault, and the follow-up fault mechanism, for CCC DC transmission system, as well as studied the impact of series capacitor size on recovery process. The research results can play a great role for improving the dynamic characteristics of CCC HVDC transmission system and its further development.

关 键 词：电容换相换流器(CCC) 电网换相换流器(LCC) 高压直流输电 换相失败 动态特性 

分 类 号：TM76[电气工程—电力系统及自动化]