串联多端高压直流系统直流线路保护方案

Protection Solution for Transmission Line in Series Multi-Terminal HVDC System

研究了串联多端直流系统保护原理。分析了传统双端高压直流系统和串联多端直流系统在继电保护视角的异同。研究了传统直流保护在串联多端直流系统中遇到的问题。为了给串联多端直流系统提供超高速、高可靠性、高灵敏度的主备保护方案,本文提出了在轻微修改平波电抗器结构和直流滤波器安装方式基础上的基于行波变化率的行波保护方案,该方案可以用作串联多端直流网络中输电线路的主保护。PSCAD模型仿真验证了所提方案的有效性。

This paper studies protection principles for a series multi-terminal DC system. The difference between conventional HVDC systems and series multi-terminal HVDC( MTDC) is analyzed from protection aspect. The problem of conventional protection principle applied in serial MTDC has been investigated. In order to supply main and back up protection with high reliability,high sensitivity and fast operation speed,a travelling wave protection solution based on the rate of changes in the local measured signals together with modified DC filter configuration is proposed in this paper which can be used as the main protection of the transmission line in series MTDC grid. Simulation on PSCAD model verifies the validity of the proposed solutions.