A new technique for the remote partial discharge monitoring of the stator insulation of high-voltage motors located in “Ex” (hazardous) locations

The authors present a paper on the application of a new technique for the remote on-line partial discharge monitoring of the stator insulation condition of in-service, high-voltage rotating machines. The technique applies wideband, ferrite-based high frequency current transformer sensors and high resolution measurement technology. This remote partial discharge monitoring technique has significant advantages when monitoring motors which are located in Ex hazardous gas zones in oil and gas and petrochemical facilities. The paper includes a technical review of published papers covering some of the history of the development of modern, on-line partial discharge sensors and measurement systems for rotating machines. This is followed by a comparison of the various partial discharge sensor options available and an introduction to the remote wideband partial discharge monitoring measurement technique employed by the authors. A case study from a recent pilot project (August 2011) where the new remote partial discharge monitoring measurement techniques were successfully trialed to measure partial discharge activity of in-service 10 kV motors in an oil processing facility is also presented.