在线监测获取的电力系统过电压波形分析

Analysis of Over-voltage in Power System Based on On-line Monitoring Device

电力系统中出现的波形、幅值及持续时间各异的多种过电压对电气设备绝缘构成了严重威胁。鉴于电力系统过电压波形包含了丰富的电力系统工作状况和状态信息,笔者重点对电力系统过电压波形进行了分析,将从变电站过电压在线监测系统获取的雷电感应过电压、投电容器组过电压、合空载线路过电压、投切空载变压器过电压、弧光接地过电压、不对称接地短路共7种典型过电压波形作为对象,分析其主要特征,并通过小波变换,使含有高频分量的过电压特征在时频域得到更好的体现,为过电压特征提取及类型识别奠定基础。

A variety of over-voltages in power system with different waveforms,amplitudes and durations seriously harm the insulation of electrical equipment.This paper analyzes the waveforms of different over-voltages from the substation over-voltage on-line monitoring system,including induced lightning over-voltage,arc grounding over-voltage,and the over-voltages due to switching capacitor bank,switching unloaded overhead lines,switching unloaded transformer,and asymmetric grounding short-circuit.Through wavelet transform,the high frequency components of over-voltage are distinguished in frequency domain for feature extraction and type recognition of over-voltages.