基于波形相关分析的双馈风电场送出线时域距离保护

双馈风机故障暂态特性与传统同步发电机不同,其短路电流成分复杂,导致基于工频相量的距离元件动作性能劣化。为了解决工频相量距离保护在双馈风电场送出线中应用时存在的问题,提出了一种基于波形相关分析的时域距离保护方案。分析了波形相似度的原理及时间窗选取的依据,通过仿真验证了所选时间窗的合理性。基于此分析,构造了时域距离保护判据,并在PSCAD/EMTDC仿真平台上搭建模型进行了测试。仿真结果表明,在不同故障类型下,所提出的时域距离保护基本不受双馈风机故障特性的影响,具有较好的动作性能。

Time-domain distance protection for transmission lines of doubly-fed wind farms based on waveform correlation analysis

The fault transient characteristics of a Doubly Fed Induction Generator (DFIG) are different from traditional synchronous generators. The short-circuit current components of the former are complex. They may lead to the deterioration of the operating performance of the distance protection based on the power frequency phasor. To solve the problems of power frequency phasor based distance protection being applied in the transmission lines of double-fed wind farms, a time-domain distance protection based on waveform correlation analysis is proposed. The principle of waveform similarity and the standard of time window selection are analyzed. The rationality of the selected time window is verified by simulation. Then, the time-domain distance protection criterion is constructed. A simulation model is built and tested using the PSCAD/EMTDC platform. The simulation results show that the proposed time-domain distance protection is basically unaffected by DFIG fault characteristics and has good performance under different types of faults. This work is supported by the National Natural Science Foundation of China (No. 51877090).