摘要
针对常规距离保护应用到传统意义的短线路时常常因为末端故障时残压小造成保护超越而退出工作的情况,简要分析了影响距离元件测量误差的因素,并利用仿真数据定量分析了短线路保护范围末端故障时,阻抗测量误差与系统阻抗和线路阻抗比(电源线路阻抗比)的关系。在此基础上提出一种根据系统阻抗和线路阻抗比自适应调整距离保护动作范围的短线路相间距离保护方案。该方案在线路发生故障时,假定故障发生在保护末端,结合实测的电源线路阻抗比按可能出现的最大测量误差调整保护范围,从而消除了短线路末端相间故障时距离保护的超越问题,保证了选择性。EMTP仿真验证,说明该方法可以有效地避免短线路末端故障时距离保护的超越问题,改善了短线路距离保护的性能。
Common distance relay is always out of work when it is used in short line,as the relay overreach is caused by small residual pressure.Factors that affect the measuring error of distance element have been qualitatively analyzed,besides,the relationship between measuring error of distance element and impedance and line impedance ratio have been quantitatively analyzed with simulation data when fault happens at the end of protection zone.The protection program that distance relay for short line can be set by use of system impedance and line impedance ratio has been advanced.In this program,fault is assumed to happen at the end of the protection wherever it happened,the great possible error can be used as the basis for the protection of adjust with real-time measuring system impedance and line impedance ratio,so that the override of distance relay for short line can be eliminated and selectivity can be ensured.EMTP simulation shows that this method eliminates the override of distance relay effectively,so the performance of distance relay for short line can be improved.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2010年第17期22-27,32,共7页
Power System Protection and Control
基金
国家自然科学基金项目(50677051
50877061)
国家科技攻关项目(2005BA208C)
国家973项目(2009CB219704)~~
