摘要
换相失败是高压直流输电最常见的故障之一,严重时会导致极停运给电网带来更大危害。一种人工换相技术—电容换相换流器(CCC),借助于换相电容上的电压能有效地减少换相失败发生概率。从CCC的数学机理出发,将CCC运用到高压直流,研究其在预防换相失败上的特性。以德宝直流枯小方式为模型,在PSCAD/EMTDC中采用优化仿真的方法通过计算换相失败临界阻抗的大小,反映CCC在预防高压直流换相失败上的特性。仿真结果表明,CCC的应用能够有效预防高压直流的换相失败。
As commutation failure is one of the most frequent faults in HVDC, it may aggravate the damage of network when bipolar unplanned outage. The capacitor commutated converter(CCC) is a method of artificial commutation. The voltages on capacitors aid in the commutation process and effectually reduce the probability of commutation failure. The mathematical model of CCC is presented firstly and its commutated characteristics are studied in the prevention of HVDC in commutation failure. Taking De-Bao DC dry small mode as a model, the commutation critical impedances are calculated by using optimal simulation module in PSCAD/EMTDC. According to the critical impedances, the characteristics of CCC's commutation-improving under grounding faults are tested. Simulation results show that the application of CCC in HVDC can effectively prevent the converter from commutation failure.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2011年第18期88-92,133,共6页
Power System Protection and Control
关键词
人工换相
电容换相换流器
高压直流
换相失败
临界阻抗
artificial commutation
capacitor commutatedconverters: HVDC
commutation failure
critical impedance