半波长交流输电线路行波差动电流特性的研究  

Study on the Characteristic of Travelling Wave Differential Current on Half-wave-length AC Transmission Lines

作　　者：汤兰西 董新洲[1] 

机构地区：[1]电力系统及发电设备安全控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084

出　　处：《中国电机工程学报》2017年第8期2261-2269,共9页Proceedings of the CSEE

摘　　要：行波差动保护是一种不受分布电容电流影响的电流差动保护原理,适用于长距离超、特高压输电线路。但行波差动保护应用于半波长输电线路时,由于线路非常长,且线路参数随频率变化,传播函数随频率的增大迅速衰减到零,因此行波差动保护的时域方程不再严格成立,在区外故障时仍会有幅值较大的高频差动电流。文中从理论上分析了线路频变参数对半波长输电线路下的行波差动保护的影响,指出使用工频分量能够有效的避开线路频变参数的影响,并通过仿真进行了验证。Travelling wave differential protection is one kind of current differential protection which is immune to distributed capacitance current and is suitable for long-distance extra/ultra-high-voltage transmission line. However, when applied to half-wave-length transmission line, because the line is very long and the line parameters are frequency-dependent, the propagation function attenuates rapidly to zero with the increase of frequency. Then the time-domain equations of travelling wave differential protection do not strictly hold and high-frequency differential current with high amplitude appears during external fault. This paper analyzed the impact due to the frequency-dependent line parameters in theory and points out that the impact can be avoided by using power-frequency component. The analysis was verified by simulation results.

关 键 词：半波长输电线路 行波差动保护 频变参数 工频分量 

分 类 号：TM77[电气工程—电力系统及自动化]