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. eywcrards: pipe-type, self-contained; leak location, dielectric fluid leaks, fluid-filled cable.
Failure mechanisms in polymer materials under voltage stress have been studied for many years. One of the most studied but least understood mechanisms is water treeing. Water trees are categorized by type and shape and have undergone a myriad of analytical testing methods to try to explain their basic formation or initiation, growth and the driving forces behind their propagation [ll. Least understood or measured are those quantities that appear when a water tree turns into an electrical tree causing failure of the insulation.There are many new diagnostic methods being developed that might provide more information on tree growth, tree initiation and charge motion during the growth period. One such method, that was successful in measuring charge motion in liquids, is being adapted for measurement of motion of charge or water in trees within polyethylene. A direct measurement of motion appears to be feasible if one looks at the changes that occur in the measuring instrumentation in response to the transport.Presented are results on the test cell designs and setup, the detection electronics and circuitry, and some preliminary tests on detected pulses in the equipment that might be attributable to motion inside the water tree.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.