Construction of 8000 A class 275 kV gas insulated transmission line

Class-8000 A 275 kV gas insulated transmission lines (GIL), 138 m and 158 m long, were completed as getaway lines in the Shin Noda substation of the Tokyo Electric Power Co. Inc. in March and May 1988, respectively. The GILs were designed for large current capacity. New techniques used to construct these lines are described. Thermal expansion and contraction of a straight section of a GIL is absorbed by varying the angle of a deflection unit. Supports were designed to absorb a ground depression. GIL units were installed with gantry cranes. Joints of enclosures were welded by an automatic welding machine.<
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