换流站直流分压器隔离放大器失电后二次电压异常原因分析

Cause Analysis of Abnormal Secondary Voltage After Power Failure of DC Voltage Divider Isolation Amplifier in Converter Station

沂南换流站调试期间发现直流分压器隔离放大器失电后会输出反向高电压,造成直流系统扰动,存在单一元件故障导致直流闭锁的隐患。为解决该问题,采用RTDS进行仿真,结果表明当直流分压器隔离放大器的额定电压为±25 V时,由于滤波回路存储能量大,失电后释放的能量不能快速衰减,输出出现反向高电压的现象,将其更换为额定电压为±10 V的隔离放大器后,无反向输出电压。

During the commissioning of Yinan converter station,it was found that the isolation amplifier of DC voltage divider would output reverse high voltage after power failure,leading to the disturbance of the DC system and hidden danger of DC lock⁃ing resulting from a single component fault.RTDS is utilized for simulation in order to solve this problem.The results reveal that when the rated voltage of DC voltage divider isolation amplifiers is±25 V,the large amount of energy is stored in the filtering cir⁃cuit,the energy released after power failure cannot decay quickly,resulting in reverse high voltage output.When the isolation am⁃plifier is replaced by one with the rated voltage of±10 V,no reverse high voltage is output.