含串补电容的超高压输电线路暂态保护判据

Transient Relay Protection Criterion for EHV Transmission Line with SCC

串补电容能提高超高压系统输电能力,但会引起超高压输电线路传统继电保护的不正确动作。运用波过程和频域响应理论,分析了含串补电容超高压线路上暂态电流在不同故障点的频域特征。小波变换提取其高频与次高频分量,通过比较高频与次高频之间的能量积分比与能量比的差异,将高频与次高频的能量积分比作为超高压输电线路暂态保护判据。测试结果表明,该判据在不同故障情形和系统运行方式下均能可靠动作,提高了保护的可靠性和灵敏度。

Series Capacitor Compensator （SCC） can increase transfer capability in Extra High Voltage （EHV） power system, but it can cause mal-operation of traditional relay protections. In this paper, the wave process theory and the frequency response theory are applied to analyze the frequency domain property of transient current at different fault po- sitions in EHV transmission line with SCC. In addition, wavelet transform is used to extract high-frequency and sec- ondary high-frequency components. Also, the differences between energy integration ratio and energy ratio of these two components are demonstrated, and energy integration ratio is chosen as the protection criterion. Testing results suggest that this criterion can correctly operate on different fault and system situations, and increases reliability and sensitivity of relay protection.