高压直流输电线路边界保护算法

Research on transient-based boundary protection for HVDC transmission lines

暂态量保护是直流线路继电保护的主要研究方向之一,分析直流输电线路及其边界的频率特性,研究直流线路区内外故障判别的边界保护原理;利用快速的改进递归小波变换提取特征差异显著的故障暂态特定频率分量幅值,并构造边界保护的实用算法.经过大量PSCAD仿真实验测试,该边界保护算法可以正确判别故障范围、识别故障极,保护性能不受故障距离、故障类型及过渡电阻等因素的影响.

The transient based protection becomes one of the main research areas for HVDC trans- mission lines protection. This paper firstly analyzed the frequency characteristics of HVDC trans- mission line and line boundary, and proposed the boundary protection principle criterion to dis- criminate the internal-faults and external-faults. Then the fault-induced transient current ampli- tude of certain frequency was extracted by fast improved recursion wavelet transformation （IR- WT）, which was also used to construct the practical algorithm of boundary protection. A large number of simulations were conducted by PSCAD. Testing results showed that the proposed pro- tection algorithm can distinguish the internal-faults and external-faults accurately, and the pro- tection performance is not affected by the fault position, fault type and fault transition resistance.