Grounding Transformer Protection: Misoperation Causes & Countermeasures in 110kV Substations
In China's power system, the 6 kV, 10 kV, and 35 kV grids generally adopt a neutral-point ungrounded operation mode. The distribution voltage side of the main transformer in the grid is usually connected in delta configuration, which provides no neutral point for connecting a grounding resistor.When a single-phase ground fault occurs in a neutral-point ungrounded system, the line-to-line voltage triangle remains symmetrical, causing minimal impact on user operations. Moreover, when the capacitiv