基于行波相位特征的海上风电柔直电缆故障保护方法的研究

Research on fault protection method of offshore wind power flexible direct cable based on traveling wave phase characteristics

电缆线路对行波的色散和衰弱性质会导致常规的行波法在电缆线路上的应用受到限制。文中提出一种适用于电缆线路的保护方案,该方案通过提取线路极线量进行相模变换,进而得到线模和地模行波分量构建整体保护方案。利用复小波Morlet获取故障模量中的相位信息,之后通过区内外故障的相位差异可以有效识别故障。基于PSCAD和Matlab仿真验证了该方法的有效性。与传统行波保护方案比较,该保护方案具有更强的耐受过阻能力。

In view of the dispersion and attenuation properties of the cable line to the traveling wave,the application of the conventional traveling wave method on the cable line is limited.In response to this problem,this paper proposes a protection scheme suitable for cable lines.The scheme extracts the pole line quantity and performs phase-to-mode conversion,and then,the line mode and ground mode traveling wave components are obtained to construct an overall protection scheme.The complex wavelet Morlet is used to obtain the phase information in the fault modulus,and the phase difference between the internal and external faults can effectively identify the fault.PSCAD and MATLAB-based simulation verifies the effectiveness of the proposed method.Compared with the traditional traveling wave protection scheme,this protection scheme has stronger ability to withstand over-resistance.