基于重合直流断路器残余电流开关的柔性直流电网故障测距

精确故障测距是确保电力系统故障快速排查清除的关键技术,其中基于行波固有频率的故障测距方法在常规直流输电系统中具有突出的技术优势.但是通过分析发现,柔性直流电网故障行波固有主频率低、可利用数据窗短,导致基于固有频率主成分的测距算法存在较大误差.针对上述问题,提出在重合闸期间重合残余电流开关创造足够长的暂态数据窗.同时,提...

Fault Location for Flexible DC Grid Based on Reclosing Residual Current Breaker of DC Circuit Breaker

Accurate fault location is the key technology for ensuring fast fault checking and clearing in power systems. The fault location method based on traveling-wave natural frequency has significant technical advantages in the line commutated converter based high voltage direct current (LCC-HVDC) system. However, through the analysis, it is found that the natural primary frequency of the fault traveling wave in the voltage source converter based HVDC (VSC-HVDC) grid is very low and the available data window is very short, which results in a large error for the location method based on the main component of natural frequency. Aiming at the above issue, it is proposed to reclose the residual current breaker (RCB) during reclosing period to create a sufficient transient data window. In addition, the fault location method based on primary/secondary frequency iterative calculation and verification is proposed. Compared with the traditional fault location method using the natural frequency at the beginning of the fault, the proposed method can significantly improve the fault location accuracy in VSC-HVDC grids. Moreover, the location deviation problem caused by the false spectral peak phenomenon of the multiple signal classification (MUSIC) algorithm is also avoided. Finally, a large number of simulation cases are carried out to verify the feasibility and superiority of the proposed method.