Field Research on 345-kY Underground Cable Systems

This paper presents the results of field testing of four 345-kV cable systems conducted by Cornell University, Ithaca, N. Y. More than three years of field testing and subsequent laboratory examination and test demonstrated that these cable systems can carry large blocks of power, 500 MVA or more depending upon governing conditions (soil, ambient temperature, load factor, etc.) at voltages up to 400-kV 3-phase, under operating conditions similar to those applying to lower voltage transmission cables installed without forced cooling or otherwise controlled temperatures. The electric utility industry now has several types of reliable under-ground cable systems available for operation with very low losses, which can be maintained at conductor temperatures of 750°to 85°C for normal and 900 to 100°C for emergency operation.