晶闸管控制电抗器故障态3次谐波分析

Analysis of the Third Harmonic Current at the Fault State of Thyristor Controlled Reactors

晶闸管控制电抗器(TCR)是静止无功补偿器(SVC)的重要组成部分,是SVC安全稳定运行的重要保证。文中根据实际TCR装置的安装及接线方式,详细给出了其运行时的各种故障态,包括引线间短路、接地短路及相控电抗器匝间短路。将直流系统的准稳态模型引入TCR装置建模,在此基础上将任意周期电流表达式推广到三相系统中,得到了TCR装置正常运行时线电流中无3次谐波,内部故障时线电流中存在3次谐波的正序及负序分量的结论。引入非特征3次谐波概念,并对TCR装置在各种故障态下存在的非特征3次谐波进行了定性及定量分析。PSCAD数字仿真结果证明了TCR装置的运行特性及故障态非特征3次谐波计算方法正确。

Thyristor controlled reactors（TCR） are critical components of static var compensators（SVCs） to ensure the safe and stable operation of SVCs.Comprehensive analysis of fault states of a TCR is given in detail.This includes line to line fault,phase to ground fault and turn to turn fault.TCRs are modeled based on the quasi-steady-state model used in HVDC and extended arbitrarily periodical current to three-phase system.The study shows that the line current of a TCR doesn＇t contain the third harmonics in the normal condition;however,it does contain positive and negative components of the third harmonics in the fault state.Non-characteristic third harmonic current is introduced and studied qualitatively as well as quantitatively.Numerical simulations using PSCAD validate correctness of the proposed method.