摘要
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。
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 current 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 dow n segment of the protection and modify the action delay time to 3 s.
出处
《南方电网技术》
北大核心
2015年第6期34-38,共5页
Southern Power System Technology
关键词
溪洛渡直流
50
Hz保护
交流谐波
励磁涌流
Xiluodu HVDC trasmission project
50 Hz protection
harmonic of AC system
magnetizing inrush current
