高压直流输电系统接地极不平衡保护改进措施研究

接地极是高压直流输电系统中最重要的组成部分之一。为了提高接地极保护可靠性,根据接地极线路参数及运行特性,提出了一种基于纵联差动保护原理的接地极不平衡保护方法。该方法将互感器装设在接地极引线的近站端和极址端,给出了纵差保护方案和保护判据,优化了保护动作策略,分析了保护动作特性。仿真结果表明,提出的接地极不平衡保护能准确辨识故障类型,准确动作隔离故障,有效降低直流系统停运概率。

Improvement measures of electrodes line unbalance protection for HVDC system

Grounding electrode is the most important part of HVDC systems. In order to improve the reliability of grounding electrodes line protection, a new unbalance current protection based on the longitudinal differential protection principle is proposed. The protection transformers are installed in the head and end of the grounding electrode line, the longitudinal differential protection scheme and criterion are presented, the original action strategy is optimized and the protection action characteristics are analyzed. The simulation results show that the unbalance protection is effective, which could accurately distinguish the fault types and act to isolate faults, and reduce the probability of HVDC shutdown.