Development of Compact 500 KV 8000 A Gas Insulated Transmission Line Study on Insulation Design

This paper describes the results of a study on insulation design performed in the development of a compact 500 kv 8000 A gas insulated transmission line (GIL). By adopting new design criteria (SF6 gas pressure: 0.6 MPa, allowable conductor temperature: 105 °C, insulator working stress: 5 kVeff/mm) instead of using conventional criteria (0.35 MPa, 90°C, 3 kVeff/mm respectively) we were able to produce a great reduction in GIL size. The behavior of conducting particles under high pressure conditions and the effectiveness of several particle control methods were studied and insulators equipped with a rib were developed for the compact GIL. A test line of 120 m length was constructed and is now undergoing the long-term field test.