基于电流相关性分析的高压直流输电线路保护

Protection for High Voltage Direct Current Transmission Lines Based on Current Correlation

在分析高压直流输电线路故障电流特点的基础上,提出了一种基于双端电流相关性保护的新方法。该方法根据区内故障时两端电流变化方向相反、而区外故障两端电流变化方向相同的特征做相关性比较,实现区内、外故障快速准确识别。此方法不需要线路两端保护装置严格时间同步,采样频率要求低,可在当前高压直流控制与保护系统的硬件条件下实现,可靠性高,实用性强,能够满足高压直流线路对保护性能的要求。PSCAD和MATLAB仿真结果验证了其可行性和有效性。

Based on the analysis of the fault currents of high voltage direct current(HVDC)transmission lines,a new protection method is proposed using the correlation of two-terminal current.The changing directions of currents on the two terminals are opposite when internal faults occur,while those are the same when external faults occur.By comparing the correlation of the above phenomenon,the proposed method achieves a quick and accurate recognition of both internal and external faults.This method does not require accurate time synchronization of protection devices on the two terminals of transmission lines,and the requirement of sampling frequency is relatively lower,which can be achieved under the hardware condition of HVDC control and protection system at present.It is reliable,practical and meets the requirements for HVDC line protection.Simulation results of PSCAD and MATLAB demonstrate the feasibility and effectiveness of the proposed method.