RF transmission-line methods for in-service probing of concentric neutral wires in underground power distribution cables

Igor Paprotny, Richard M. White, Kanna Krishnan
2010 2010 IEEE International Symposium on Electrical Insulation  
Failure of concentric neutral (CN) wires in an underground power distribution cable can drastically reduce its useful life. New on-line approaches are needed to assess the deterioration of the CNs and to prevent unscheduled service disruptions. In this paper, we present new methods for probing the integrity of CN wires in underground power distribution cables using RF-waves. The primary advantage of our techniques compared to traditional CN diagnostics is the easy of applying our methods to
more » ... gized underground power distribution cables. This paper briefly describes two methods for transmitting RFwaves through underground cables: a surface RF-wave, also called the Goubau Wave (GW), guided by all the CNs within the cable, and an RF-wave coupled to a two-wire transmission line composed of adjacent CNs. We focus on the use of GW to probe for CN degradation, due to good coupling of the wave to the underground cable, We show experimental results demonstrating the change in the signature of the transmitted GW signal through a section of degraded (broken) CNs.
doi:10.1109/elinsl.2010.5549821 fatcat:xqw5ut5z5vdqrpb4lwkbaq7mvi