CAJ | 학술논문

针对溪洛渡高压直流输电工程, 研究了送端换流站近区投入大型变压器时的励磁涌流对直流50 Hz保护的影响. 在理论分析和仿真计算的基础上, 分析了影响直流电流50 Hz分量的因素及调试过程中50 Hz保护动作的原因,得出了以下结论: 逆变侧直流电流50 Hz分量有效值与送端交流电压2次谐波含量呈线性关系, 与直流功率、故障发生的时刻基本没有关系; 直流双极运行和单极金属方式运行时, 直流线路对直流电流50 Hz分量有放大作用. 为了避免送端励磁涌流触发50 Hz保护动作闭锁直流, 提出了取消该保护的降功率段并将动作段延时改为3 s的改进措施.
침대계락도고압직류수전공정, 연구료송단환류참근구투입대형변압기시적려자용류대직류50 Hz보호적영향. 재이론분석화방진계산적기출상, 분석료영향직류전류50 Hz분량적인소급조시과정중50 Hz보호동작적원인,득출료이하결론: 역변측직류전류50 Hz분량유효치여송단교류전압2차해파함량정선성관계, 여직류공솔、 고장발생적시각기본몰유관계; 직류쌍겁운행화단겁금속방식운행시, 직류선로대직류전류50 Hz분량유방대작용. 위료피면송단려자용류촉발50 Hz보호동작폐쇄직류, 제출료취소해보호적강공솔단병장동작단연시개위3 s적개진조시.
The impact of the magnetizing inrush current of large transformers at the sending end of Xiluodu HVDC transmission project on the 50 Hz protection is studied in the paper. Through theoretic analysis and simulation, the infuencing factors of 50 Hz component in DC current and the causes of 50 Hz protection action during the system commissioning are researched. The conclusions are:the rms cur-rent of 50 Hz component in DC current near the inverter end has linear relationship with the second order harmonic voltage at the sending end, commutation bus, and has no relationship with the DC power or the moment of failure;DC transmission lines can magnify the 50 Hz component in DC current in the bipole or monopole operation mode. To avoid triggering the 50 Hz DC protection and blocking the DC transmission, it is recommended to cancel the power down segment of the protection and modify the action delay time to 3 s.