三峡右岸电站500kV母线保护配置方案探讨

Discussion on 500 kV bus protection configuration of Three Gorges right bank hydropower station

三峡右岸电站500kV母线采用3/2接线方式,在主母线上设有分段开关。分段开关的分合状态等于位置接点或操作压板,这些辅助开关量不能真实反映分段开关的实际状态,存在着不对应的过程,特别是开关量出错或者误操作的情况下,有导致母线保护误动的问题。分析了现有配置方案中存在的误动问题,利用分段开关两侧都装有电流互感器的有利条件,在母线保护中配置多个不同选择范围的差动保护,运用数字逻辑电路的分析方法,通过差动动作数据的逻辑组合反映出分段开关的运行方式,能够真实反映分段开关的实际状态,解决了现有配置方案中误动的问题。

The one-and-half breaker scheme is applied to 500 kV bus of Three Gorges right bank hydropower station and its main bus is equipped with the segment switch. The on-off state of the segment switch is taken as the state of its position contact or hard strap, but these auxiliary binary variables cannot truly reflect its actual state,which may lead to bus protection malfunction,especially when there is signal error or misoperation. The problems existed in current configuration scheme are analyzed and the solution is proposed： as the segment switch is equipped with CTs at both sides and several differential protections with different selection ranges are configured in bus protection,the method of digital logic circuit analysis is used to obtain the operational mode of segment switch by analyzing the logic combination of differential operating data,which can truly reflects its actual state.