Leak location in fluid filled cables using the PFT method

A new method of pinpointing dielectric fluid leaks on pipe-type and selfcontained cables using perfluorocarbon tracer (PFT) is presented. The method has successfully been used on the Con Edison transmission system to locate leaks of dielectric fluid on both types of cables. Application of the PFT technique does not require feeder deenergization and provides major advantages over the conventional method of freeze and pressure testing. Description ofthe method and results of field application are presented in the paper.