沙角B电厂6.3kV厂用电系统接地保护的配合

Coordination of Grounding Protections for 6.3kV Auxiliary Power System in Shajiao B Power Station

沙角B电厂6.3kV厂用电系统存在各保护配合不协调的问题。为此,根据6.3kV厂用电系统高阻接地方式的特点,分析了各保护装置的灵敏性及整定配合,通过理论计算和试验验证,提出了修改保护整定值的建议。具体意见是:零序过电流保护的整定值由0.5A调整至0.8A,零序方向保护的整定值由12.5mA调整至10m A,1/2段母线零序过电压保护的整定值由30V调整至10V,其他母线零序过电压保护的整定值由30V调整至15V。

The protections for the 6.3 kV auxiliary power system in Shajiao B Power Station are not concerted. Consequently, an analysis is made of the sensitivity and setting coordination of thc protections according to the features of the high-resistance grounding mode of the system. Through theoretical calculation and test verification, suggestions are made to improve the protection settings. It is presented that the setting of the zero-sequence overcurrent protection be adjusted from 0. 5 A to 0.8 A, that of the zero-sequence directional protection from 12.5 mA to 10 mA, that of the zero-sequence overvoltage protection for 1/2 bus section from 30 V to 10 V, and that of the zero-sequence overvoltage protection for other buses from 30 V to 15 V.