Development and installation of a 69 kV aerial cable system

Several years ago, the growing demand for higher reliability, concern over the possible effects of magnetic fields and difficulty in obtaining right-of-way resulted in work by the Electric Power Research Institute (EPRI) and several utilities into the feasibility of using covered conductors for transmission voltage applications. The preliminary work suggested the possible use of covered conductors through 138 kV. A 69 kV Aerial Spacer Cable (ASC) system has been developed and tested. By permitting a significant reduction in the phase separation the heavily covered phase conductors reduce right-of-way requirements and magnetic field strength. Reliability is improved due to the ability of the system to tolerate momentary contact with trees or other objects. In cooperation with the Omaha Public Power District the first 69 kV Aerial Spacer Cable system was installed and energized in December of 1996. To date the system has not had any outages and system components have operated without mechanical failure.