相差高频保护中操作元件比相动作判据的研究

传统相差高频保护通过比较被保护线路两端正序电流和K倍负序电流之和的相位来区分区内、区外故障,但对于超高压长距离输电线路而言,由于重负荷及分布电容的影响, 采用这种动作判据的保护动作性能不够理想。文章采用ATP 软件对传统比相动作判据的性能进行了仿真分析,在此基础上提出了采用正序电流的故障分量和负序电流之和作为操作电流进行两侧电流相位比较的动作判据,并将其与传统动作判据进行了仿真比较,表明所提出的判据能大大提高相差高频保护的性能。

Study on Phase Comparison Criterion of Operating Component in Phase Differential High Frequency Protection

In order to protect EHV transmission line, traditional phase differential high frequency protection distinguishes internal fault from external fault by the criterion that compares the phase of the sum of positive sequence current and K times of negative sequence current at one terminal with that at another terminal. Because of the influences of heavy load and distributed capacitance of long distance EHV transmission line, the operating performance of the protection adopting such criterion is not satisfied. Using ATP software, the authors carried out the simulation on traditional phase comparison criterion, on this basis a new operating criterion, which compares the phase of sum of fault component of positive sequence current and negative sequence current at one terminal with that at another terminal, is proposed. The proposed operating criterion is compared with traditional operating criterion by simulation and the results show that the performance of phase differential high frequency protection can be evidently improved by use of the proposed operating criterion.