基于能量比值分析的直流输电线路故障判别

Fault Identification of DC Transmission Lines Based on Energy Ratio Analysis

针对高压直流输电线路跨域广,遭受雷击概率较高,易引起输电线路故障的问题,提出了一种基于能量比值分析的故障识别方法。在考虑发生雷击故障或接地故障时,引起输电线路暂态能量发生改变,且雷击时的故障能量与接地故障时的故障能量不同的特征,通过从能量的角度出发,提出了利用S变换将输电线路各频带的能量进行分离,提取出特定频带的能量进行比值分析。基于EMTP/PSCAD搭建220kV高压直流输电线路模型,仿真结果表明其方案可以很好地识别雷击故障和接地短路故障。

HVDC transmission lines,being long in distance and crossing complex natural environments,are prone to lightning and short to ground faults.Aiming at this problem,a novel fault identification method is proposed based on energy ratio.Considering the transient energy variation of transmission lines caused by lightning faults or short to ground faults,and the difference of fault energy characteristics between lightning fault and grounding fault,it is proposed from the perspective of energy to use the S-transformation to separate the energy of each frequency band of the transmission line,and to extract the energy of a specific frequency band for ratio analysis.A 220 kV HVDC transmission line model is constructed using EMTP/PSCAD,and the simulation results show that the proposed method can well identify the lightning faults and short-to-ground faults.