特高压输电线路计算功率法差动保护  

Differential Protection Based on Calculated Power for UHV Transmission Lines

作　　者：王利平[1] 王晓茹[1] 

机构地区：[1]西南交通大学电气工程学院,四川省成都市610031

出　　处：《中国电机工程学报》2013年第19期174-182,5,共9页Proceedings of the CSEE

摘　　要：特高压输电线路分布电容对电流差动保护影响大,而差动电流补偿算法要求准确的线路参数,目前无法准确地实时测量线路参数,针对此问题,提出一种计算功率法差动保护,该保护原理与线路参数无关。基于分布参数线路二端口网络模型,分析了正常运行、区外故障和各种区内故障下的计算功率差动量和制动量。理论分析和EMTDC/PSCAD仿真表明,该保护性能不受对地并联电抗支路(分布电容容抗和线路并联电抗器)的影响,选相准确,抗过渡电阻能力强,差动门槛值的整定简单,且与线路参数无关。提出了计算功率的工程实用算法,计算量小,适用于目前的微机保护装置。The performance of current differential protection is significantly influenced by the distributed capacitance of ultra high voltage （UHV） transmission lines. The compensating distributed capacitance algorithm is based on accurate transmission-line parameters but these parameters can not be accurately measured in real time. To solve the problem, the paper proposed a novel differential protection algorithm based on calculated power, which is independant of transmission-line parameters. Using the two-port network theory of the distributed-parameter line model, the paper calculated the differential calculated power and restraint calculated power during three kinds of operating conditions： normal, external faults and all kinds of internal faults. Theoretical analysis and simulation on EMTDC/PSCAD show that the algorithm is independant of shunt reactors branch including distribution capacitor capacitance and line shunt reactors, and has the characteristics of accurate faulted phase selection and high fault-grounding resistances tolerance. The threshold value of differential calculated power can be set in a simple way and is irrelevant to the line parameters. The algorithm for engineering application was proposed, which does not need complex computation and is suitable for applications in micro-computer protection device.

关 键 词：差动保护 计算功率 特高压输电线路 二端口网络理论 

分 类 号：TM77[电气工程—电力系统及自动化]