摘要
为解决目前直流线路主保护不能反映高阻接地故障的问题,提出了一种检测电流首峰值时间(the first peak time of fault current,FPTFC)的直流线路保护新原理。首先,对两极直流母线上的FPTFC变化特性进行解析与仿真研究,得到其在区内、区外故障情况下的一般变化规律。根据所得规律,安装于一极上的新型保护,以本端换流站另外一极直流母线上的FPTFC作为保护特征量,从而消除了过渡电阻对保护性能的影响。保护功能分两段实现,I段用于区内故障识别,约可以保护本极线路全长的70%;II段用于本极线路末端故障与区外故障的辨识,与I段共同保护线路全长。PSCAD/EMTDC环境下的相关仿真结果验证了新型保护的可行性与实用性。
In allusion to the defect that the high-impedance grounded fault cannot be detected by current main protection for HVDC transmission lines, based on the detection of the first peak time of fault current （FPTFC） a new protection principle for HVDC transmission lines is put forward. Firstly, the varying characteristics of FPTFC of two polar DC buses are analyzed and simulated to obtain their common varying regularity under fault occurred inside/outside the protection zone. Based on the obtained regularity, the FPTFC of another polar DC bus in local converter substation is taken as the characteristic value of the protection for the new type of protective relaying installed on one of the two polar DC buses, thus the affect of transition resistance on protection performance can be eliminated. The function of the proposed new protective relaying is realized by two protective sections： the section I is used to identify the fault occurred inside the protection zone and its protection range is about 70% of the full length of the HVDC line connected to the polar DC bus installed with the new protective relaying; the section II is used to identify the fault occurred at the end of the HVDC line or the fault occurred outside the protection zone, thus the full length of the HVDC line can be protected by the combination of section I and section II. The validity and practicality of the proposed new protective relaying are verified by results of simulation in PSCAD/EMTDC environment.
出处
《电网技术》
EI
CSCD
北大核心
2013年第9期2396-2402,共7页
Power System Technology
基金
国家自然科学基金项目(51077055)
高等学校博士学科点专项科研基金资助项目(20100172110031)~~
关键词
直流输电
线路保护
主保护
首峰值时间
HVDC transmission
line protection
main protection
the first peak time of fault current （FPTFC）
