DEVELOPMENT OF COMPACT 500 kv 8000 A GAS INSULATED TRANSMISSION LINE - STUDY ON INSULATION DESIGN.

By adopting new design criteria (SF//6 gas pressure: 0. 6 MPa, allowable conductor temperature: 105 degree C, insulator working stress: 5 kVeff/mm) instead of using conventional criteria (0. 35 MPa, 90 degree C, 3 kVeff/mm respectively) we were able to produce a great reduction in GIL (Gas Insulated Line) 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. More than one and one-half papers of discussion of the paper are appended.