Line trapped charge discharging characteristic of gas insulated magnetic voltage transformer

Line charge, which is trapped after opening the line circuit breaker of a long overhead transmission line or power cable, is discharged through magnetic voltage transformers (VTs) or shunt reactors, if either is connected to the power line or cable. Although this duty is very important for a VT, there is no description or specification on the relevant international standards. The authors analyze the discharging conditions and their effects on the gas insulated magnetic VT design and propose a specification based on full-scale discharging tests at a laboratory using gas insulated magnetic VTs with various voltage ratings