【摘要】 PT二次两点接地且接地点之间接地网导通不良会影响继电保护装置动作行为。针对一起因继电保护动作异常引起故障停电范围扩大的安全事故,分析了电网故障过程中在PT二次电压正常时继电保护的动作行为,和PT二次两点接地且接地点之间接地网导通不良造成接地网电位串入PT二次回路时继电保护的动作行为。接地网电位的串入引起保护装置安装处电压值出现偏差,影响保护装置元件计算结果,保护装置拒动或误动,造成电网事故扩大。更多还原

【Abstract】 High resistance between two points grounding in PT secondary circuit tends to affect the operation behavior of relay protection equipment.In view of a safety accident of power failure expansion caused by abnormal operation of relay protection,operation behavior of relay protection is analyzed,both when the PT secondary circuit works in proper operating voltage and when under abnormal circumstance caused by the high resistance between two points grounding in PT secondary circuit.The introduction of the potential of grounding grids leads to voltage deviation of relay protection installation location,alters the calculation result of relay protection,which in consequence results in malfunction or failure of relay protection and the expansion of power failure ultimately.更多还原