基于PSCAD/EMTDC的高压直流输电线路保护仿真研究

本文在PSCAD/EMTDC平台上建立了实用的直流输电线路行波保护系统模型。通过分析高压直流线路发生故障后的特点,按照行波保护的原理,利用直流线路发生故障瞬间,线路上产生的暂态电流电压行波的幅值和方向不受控制系统作用影响的特点,通过计算直流电压下降率和直流线路故障前后的电压电流行波差值,来判断直流线路是否发生故障。在南方电网贵广直流输电系统仿真模型上对所建立的直流输电线路行波保护系统进行了仿真测试,通过设定极1整流侧直流线路发生接地短路故障,验证行波保护系统的动作情况,仿真测试结果证明了本文所建立的线路行波保护系统的正确性和实用性。

Simulation of Line Protection of HVDC Transmission Based on PSCAD/EMTDC

This paper develops the practical traveling wave protection system of HVDC transmission lines based on PSCAD/EMTDC.The paper analyzes the fault characteristics of HVDC transmission lines.Upon the theory of traveling wave,the value and direction of the transient current and voltage due to the short circuit fault happened in the DC line will not be affected by the control system of HVDC.So the short circuit fault of the DC line can be detected by calculating the decline rate of direct voltage and comparing the setting values with the transient traveling wave of DC current and voltage after the fault.The traveling wave protection model of HVDC transmission lines is applied into the simulation model of the Gui-Guang HVDC transmission in the South Grid of China with a grounded fault near the rectifier of the transmission line in pole 1.The simulation result proves that the proposed traveling wave protection system of HVDC transmission lines is correct and can be applied into the real HVDC transmission system.