基于故障行波相似度的风电送出线路保护研究

Research on Wind Power Transmission Line Protection Based on Fault Traveling Wave Similarity

分布式风电场站并入配电网后,由于其短路电流幅值受控、频率偏移等特点,传统配电网三段式电流保护难以准确判别风电送出线路故障。提出一种基于故障电流行波相似度的配电网风电送出线路快速保护方法,以快速可靠保证配网的稳定安全运行。首先分析了送出线路两端电源故障电流输出差异,利用故障初始阶段电流行波波形差异性提出相似度纵联保护方法,小波模极大值用于启动保护,通过改进的最长公共子序列算法度量两端波形相似度完成故障判别。最后仿真结果表明了所提方法优越的快速性和可靠性。

After the distributed wind farm stations are integrated into the distribution network,due to the characteristics of wind farm short-circuit current amplitude control and frequency offset,the traditional three-stage current protection of distribution network is difficult to accurately identify the fault on the wind power transmission line.Based on the similarity of fault current traveling waves,a fast protection method for wind power transmission lines in distribution networks was proposed to ensure fast and safe operation of distribution networks.First,the differences in the supply fault currents at the two ends of the transmission line were analyzed.A similarity pilot protection approach was proposed by exploiting the difference in the current travelling waveforms during the initial phase of the fault.The wavelet mode maximum was used for the start of protection.With the improved longest common subsequence algorithm,the waveform similarity at both ends was measured for fault discrimination.Finally,the simulation results demonstrate the excellent speed and reliability of the proposed method.