THE APPLICATION OF ULTRA-HIGH-FREQUENCY PARTIAL DISCHARGE MEASUREMENTS TO GAS-INSULATED SUBSTATIONS

This paper deals with the application of the Ultra-High-Frequency meth od (UHF-method) for the detection of partial discharges (p.d.) in gas- insulated substations (GIS). First a review of the GIS-relevant part o f the theory of electromagnetic wave propagation in the UHF-range (300 MHz - 3 GHz) is given. New information considering the attenuation du e to reflections of UHF-signals at spacers is presented. For the used sensors to pick up the UHF-signals inside the GIS a new description as antenna valid in the UHF-range is introduced. The second part of this paper presents measurements with the UHF-method to compare the sensit ivity to the conventional p.d, detection method according to IEC-270. Practical conclusions are drawn from these new results for the applica tion of the UHF-method for on-site testing and on-line-p.d. monitoring of GIS.