单一测量元件故障导致直流测量系统切换后保护误动的反措

摘要

On March 4, 2014, the DC over-voltage protection (59/37DC-II) in Yun-Guang UHVDC project acted, leading to a DC tripping event, which exposes a problem that a DC protection incorrect tripping due to single measuring unit fault is possible after DC measure system switching. Based on analysis of this event it is found that 59/37DC-II protection and some other protections based on IIR2 filtering function model such as the traveling wave protection(WFPDL), undervoltage sensing protection (27du/dt), grounding electrode bus protection (87EB) have the same problem that the data can not follow immediately the DC measure system switching. The problem in 59/37DC II protection is solved by introducing the TDM bus swiching signal and canceling the average proceccing of protection differentials. The problems in WFPDL, 27du/dt, 87EB protection are solved by replacing the IIR2 filtering function model with the IIR2S filtering function model and using the TDM bus switching signal. Simulations and on-site operations verify the correct-ness of the proposed measures.%2014年3月4日云广直流发生了直流过压保护(59/37DC-II)动作跳闸事件,暴露出直流测量系统切换不能避免单一测量元件故障导致的保护误动问题。对该事件的分析发现,59/37DC-II保护和基于IIR2滤波功能模块的行波保护(WFPDL)、电压突变量保护(27du/dt)、接地极母线保护(87EB)在测量系统切换后都存在着数据不能及时跟随问题。通过引入TDM总线的切换信号,并取消59/37DC-II段保护的保护差值平均值处理的方法解决了59/37DC-II保护的问题,采用IIR2S滤波功能模块替换IIR2滤波功能模块,并利用TDM总线切换信号进行处理,解决了WFPDL、27du/dt、87EB保护的问题。仿真和现场运行情况证实了所提措施的正确性。