525-kV Self-Contained Oil-Filled Cable Systems for Grand Coulee Third Powerplant Design Proving Tests

This paper discusses the testing requirements and results of the tests on the proposed designs for the 525-kV self-contained oil-filled cable systems to be installed for the first three transformer circuits at Grand Coulee Third Powerplant. Details of the test assemblies, methods, controls, measurements, problems, and results are given for tests that: confirm the cable system rating; prove electrical and thermal stability; demonstrate handling capability and mechanical integrity; compare 50 Hz and 60 Hz power factors; and assure satisfactory operation at ambient temperatures as low as minus 27° C.