基于小波能量相对筛的HVDC输电线路单端保护方法

A Single-ended Protection Method for HVDC Transmission Lines Based on Relative Entropy of Wavelet Energy

摘要:

高压直流 ( high voltage direct current，HVDC) 输电线路目前配置的行波主保护动作速度快，但灵敏性不足，耐过渡电阻能力差，后备保护能够弥补这一缺点，但存在延时时间长的问题。为提高保护的灵敏性和可靠性，研究了基于小波能量相对熵的单端暂态量保护。利用平波电抗器和直流滤波器内外电流特定频带能量的差异，构造单端电流小波能量相对熵判据，实现区内外故障的识别。基于 PSCAD/EMTDC 的仿真结果表明，该保护原理能快速、可靠地识别区内外故障。

Abstract:

The presented main protection for HVDC transmission lines acts fast，but it has low sensitivity and low anti-resistance ability. The backup protection can compensate this disadvantage but its operation speed is slow. In order to improve the reliability and sensitivity of the protection，the single - ended transient protection based on relative entropy of wavelet energy is studied. The internal fault and external fault are discriminated by the relative entropy criterion which is constructed using the differences of the currents on both sides of the smoothing reactor and DC filter under specific frequency bands. Simulation results based on PSCAD / EMTDC show that the proposed protection scheme can discriminate the internal fault and external fault quickly and reliably.