高压输电线路短路故障早期检测研究

Research on early detection for short-circuit fault in high-voltage transmission line

为提高电力系统供电可靠性和电能质量,高压快速转换开关应运而生,而现有故障检测技术大多需要数个毫秒的时间,对高压快速转换开关而言略为缓慢。提出将小波变换应用于高压输电线路短路故障早期检测上,采用小波变换第四尺度细节分量作为故障特征量。基于Matlab/Simulink仿真平台,通过设置合理的短路判断阈值,可将短路故障与空载合闸、功率补偿及负荷投切等系统操作引起的过电压和涌流区分开来,验证了此方法的可行性。仿真结果表明,小波变换方法最短可在0.2 ms时间内辨识出短路故障。小波变换短路故障早期检测技术与高压快速转换开关的有机结合将为电力系统可靠稳定运行提供有利的保障。

High-voltage fast transform switch is applied to improve the reliability of the power supply and power quality. However, most of the existing fault detection technologies need several milliseconds to detect short-circuit fault. It＇s a bit longer for fast transform switch. In this paper, wavelet transform is applied to high-voltage transform line on the early detection, being characterized with the fourth dimension detail component of wavelet transform. The method is verified on Matlab/Simulink platform. It can separate short-circuit fault from overvoltage and inrush current caused by no-load switching, load switching and reactive power compensation. The simulation result shows the wavelet transform can identify the fault within 0.2 ms. Combining wavelet transform early detection technology with high-voltage fast transform switch will contribute to a stable and reliable power system.