具备应对过负荷能力的距离保护原理  

Principe of Distance Protection Capable to Cope With Overload

作　　者：柳焕章[1] 周泽昕[2] 王德林 王兴国[2] 

机构地区：[1]华中电网有限公司,湖北省武汉市430077 [2]中国电力科学研究院,北京市海淀区100192 [3]国家电力调度控制中心,北京市西城区100031

出　　处：《电网技术》2014年第11期2943-2947,共5页Power System Technology

基　　金：国家电网公司科技项目(适应大电网运行的继电保护应用策略及协调控制技术深化研究)

摘　　要：针对大停电事故中距离保护因过负荷误动的问题,通过比较电压平面和阻抗平面上的过负荷特征,提出了基于电压平面的距离保护应对过负荷策略。本策略分2部分:基于Ucosφ的过负荷与相间故障识别方法,过负荷时Ucosφ较大,相间故障时Ucosφ较小;基于正序补偿电压和相补偿电压相位特征的过负荷与单相接地故障识别方法,单相经过渡电阻接地故障时,正序补偿电压超前相补偿电压相位,线路过负荷时,正序补偿电压与相补偿电压相位一致。根据上述特征实现了过负荷与故障的区分,避免了距离保护因过负荷误动。In allusion to the malfunction of distance protection caused by overload during large-scale blackout,through comparing the fault features on voltage plane and impedance plane a voltage plane based strategy of distance protection to cope with the overload is proposed.The proposed strategy is divided into two parts：one of them is the Ucosφ based method to identify overload and phase-to-phase faults,since the value of Ucosφ is smaller under the overload condition and larger under the fault condition;the another of them is a method to distinguish single-phase earth fault from the overload,which is based on the phase characteristics of positive-sequence compensated voltage and that of phase compensated voltage,for single-phase earth fault via transition resistance,the phase of the positive-sequence compensated voltage leads to that of the phase compensated voltage,and for the overload the phase of the positive-sequence compensated voltage is consistent with that of phase compensated voltage.Based on above-mentioned features the overload can be distinguished from grid faults and the malfunction of distance protection due to the overload can be avoided.

关 键 词：输电线路 距离保护 过负荷 电压平面 正序补偿电压 相补偿电压 Ucosφ 

分 类 号：TM773[电气工程—电力系统及自动化]