中文摘要：

基于不同交流系统故障下的直流系统等值故障分量电流暂态特性,分别对直流馈入环境下输电线路电流差动保护故障分量判据和稳态量判据的动作特性进行了分析。研究表明在一定条件下直流系统将降低电流差动保护动作的灵敏性,且故障分量判据受影响的程度更为严重;基于PSCAD/EMTDC的仿真验证上述理论分析的正确性。

英文摘要：

Based on the characteristics of equivalent DC-system power-frequency current variants under different fault conditions of AC system,the influence of HVDC system on the performance of two differential current relays using fault current and fault component current for transmission lines is analyzed respectively in the paper.It shows that the infeed of HVDC system can make the sensitivity of current differential relay lower under certain conditions,and the impact on fault component current differential relay is more serious.Extensive simulations using PSCAD/EMTDC testify the conclusion’s correctness.