摘要
高压直流输电运行于单极大地回路方式时,太阳耀斑活动产生的地磁感应电流会使变压器或保护用电流互感器产生直流偏磁现象。当直流偏磁电流进入交流系统后,阻抗继电器的测量阻抗中会产生一个附加阻抗,使阻抗继电器的测量阻抗变大,从而导致距离保护出现欠范围拒动作。文章建立了相应的输电线路距离保护系统模型,推导出了直流偏磁条件下阻抗继电器测量阻抗表达式,同时为了直观的衡量直流偏磁电流对测量阻抗的影响,定义出了直流偏移系数,通过分析不同直流偏移系数条件下的距离保护动作特性,并利用PSCAD/EMTDC仿真软件在不同直流偏移系数条件下进行仿真分析,验证了理论分析的正确性。
When High -voltage direct current（HVDC） project operates in monopolar mode, the ground induced cur-rent（GIC） produced by solar flare activity will cause DC magnetic bias phenomena of transformer or current transform -er for protection.While the direct current flows into the power system , an additional impendence will be produced -shown in the impedance relay measurement , which will expand the impedance measuring value , so as to make the im-pedance relay under -reaching range refuse to operate.A corresponding power transmission line distance protection system model has been established , and the impedance relay measuring impendance expression in DC magnetic bias condition has been deduced.Meanwhile, in order to measure the affect of the DC migration bias on impedance meas -urement intuitively, a concept of DC magnetic coefficient has been put forward .The analysis of the operating charac-teristics of distance protection and the simulations based on PSCAD /EMTDC in different DC coefficients verify the cor-rectness of the theoretical analysis.
出处
《电测与仪表》
北大核心
2014年第15期42-47,共6页
Electrical Measurement & Instrumentation
基金
国家自然科学基金资助项目(51377016)
关键词
直流偏磁
距离保护
测量阻抗
直流偏移系数
动作特性
DC magnetic bias
distance protection
measured impedance
DC coefficient
operating characteristic
