Study on the Requirements for the 10 kV Voltage Transformers Considering Live Working

Voltage transformers can explode during live disconnection, jeopardizing the safety of operating personnel. To address this issue, this paper constructs an ATP-EMTP simulation model for the connection of 10 kV distribution network voltage transformers to the primary system. It analyzes the impact of live disconnection transient processes and evaluates the safety of transformer operation under various conditions. Additionally, safety measures for live disconnection of voltage transformers are proposed. Research findings reveal that electronic voltage transformers exhibit no hazardous overvoltages or overcurrents during live disconnection. On the other hand, electromagnetic voltage transformers experience transient overvoltages and overcurrents upon live connection. The method of connecting transformers to the primary system and the grounding approach on the high-voltage side significantly affect the safety of transformer operation. During live operations, mitigating measures can involve the insertion of damping resistors between the transformer and the primary system or grounding the high-voltage side of the transformer through linear resistors to mitigate these effects.