超高速保护中雷电干扰识别的暂态法研究

Study of Transient Approach of Discriminating Lightning Disturbance in Ultra-high-speed Protection

雷电干扰可能会造成基于行波或暂态量的超高速输电线路保护误动作。经对雷击和短路故障时的电流故障分量进行信号能量分布和波形的分析发现：普通短路故障与雷击引起强故障时的暂态能量主要集中在低频带；雷电干扰与雷击引起弱故障时的暂态能量主要以高频为主；相对于雷电干扰和普通短路故障,雷击引起弱故障时的行波截波特征非常明显。据此,提出了基于小波变换的雷电干扰识别的暂态方法。EMTP仿真显示该识别方法是可行的。

The application of ultra-high-speed protection based on traveling-waves or transient components may mal-operate in case of lightning strokes on transmission lines. This paper analyzes the spectra and traveling-wave waveforms of current transient components and finds the differences in energy distribution and waveform. The characteristic differences are as follows： the signal energy of short-circuit faults and lightning-induced severe faults mainly focuses at low-frequency band; the signal generated by lightning disturbance and lightning-induced weak faults contains abundant high- frequency components; Relative to lightning disturbance and short-circuit faults, the chopped wave caused by lightning-induced weak faults is obvious. According to these differences, the paper proposes a transient approach using wavelet transform to identify lightning disturbance. EMTP simulation tests indicate the transient approach is feasible.