Practical implementation of ultrawideband partial discharge detectors

It is shown that significant improvements in partial discharge (PD) measurement can be achieved through the use of ultrawideband (UWB) coupling techniques. These enhancements are principally in the areas of increased sensitivity, external noise rejection, and better understanding of the physics of the PD process. Examples of the improvements achievable by the use of UWB techniques are discussed for the cases of rotating machines and GIS. A new PD coupler which has a frequency response extending into the GHz range is demonstrated to enable reliable discrimination of PD signals from noise on operating turbine generators. Preliminary results from a fundamental study on PD in epoxy resins, show that there are two types of PD phenomena, `fast´ and `slow´