基于小波变换的HVDC输电线路电压行波保护新方案

分析了高压直流输电线路故障电压行波的特点,提出了一种基于小波变换的新型电压行波保护.利用小波变换对电压行波作多尺度分解,将分解后较高尺度的模极大值及其附近若干个小波分解系数的平方相加,结果与整定值比较构成保护判据.一方面,高尺度的小波变换能够降低噪声的干扰;另一方面,由于平方和的作用有利于保护对经高阻接地故障的准确判断.大量仿真及理论分析表明该方案具有较高的灵敏度和可靠性.

A Novel Scheme of HVDC Transmission Line Voltage Traveling Wave Protection Based on Wavelet Transform

On the basis of analyzing characters of HVDC transmission line fault voltage traveling wave, a novel voltage traveling wave protection scheme based on wavelet transform is presented. After multi-resolution wavelet on voltage traveling wave, the square of the higher level wavelet modulus maxima and some nearby it are added. The result and fixed value make of protection criterion. One hand, high level wavelet can recede noise interfere; on the other hand, square sum makes protection exactly estimate inner grounded fault with large resistant. A great deal simulation and theory analysis indicate this scheme has better delicacy and reliability.