CAJ | 학술논문

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。
고압직류수전운행우단겁대지회로방식시，태양요반활동산생적지자감응전류회사변압기혹보호용전류호감기산생직류편자현상。당직류편자전류진입교류계통후，조항계전기적측량조항중회산생일개부가조항，사조항계전기적측량조항변대，종이도치거리보호출현흠범위거동작。문장건립료상응적수전선로거리보호계통모형，추도출료직류편자조건하조항계전기측량조항표체식，동시위료직관적형량직류편자전류대측량조항적영향，정의출료직류편이계수，통과분석불동직류편이계수조건하적거리보호동작특성，병이용 PSCAD /EMTDC 방진연건재불동직류편이계수조건하진행방진분석，험증료이론분석적정학성。
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.