整流器出口设置平衡电阻桥接地方案的研究

Research on Necessity and Scheme of Balanced Resistance Bridge Set for Rectifier Outlet

超/特高压变电站存在大量整流器独立供电的直流不接地电源系统,这些系统对地无电气联系,不能测量正负极对地电位。文中分析了直流不接地系统在变电站运维检修期间存在的问题,尤其在隔离开关控制回路故障检查期间遇到的难题。提出整流器内部出口配置平衡电阻桥接地,使直流系统对大地建立电气联系的方案。所提方案解决了变电站直流不接地系统不能测量正负极对地电压和检测对地绝缘问题,极大方便了直流系统运维检修工作,同时不影响原直流系统工作特性。建议整流器生产厂家据此改进产品出口电路。

Ungrounded Direct Current （DC） System powered by independent rectifier is extensively used in EHV and UHV power sta-tion. These systems have no electrical contact with the earth, so there is no way to measure the voltage of positive and negative pole toground. This paper analyzes the problems existing in ungrounded DC systems＇ operation and maintenance work, especially the problemsencountered during the fault check work on switches control circuit. A scheme that a balanced resistance bridge is set on rectifier＇s out-let for setting up electrical connection between the system and earth. This scheme solves the problem that voltage and insulation betweenungrounded DC system＇s positive and negative pole to ground can＇t be measured, which greatly facilitates the operation and maintenancework of the DC system. Meanwhile, the operating characteristics of the original DC system are not affected. It is recommended that rec-tifier manufacturers improve the product outlet circuit accordingly.