So far

researchers have not reached an agreement on the relationship between discharge signal and dis-charge capacity in application of UHF method to monitoring GIS partial discharge

which leads to the absence of a uniform calibration standard for adopting UHF method to monitor the apparent discharge magnitude of GIS. Conse-quently

difficult determination of the GIS partial discharge severity restricts the development of GIS partial dis-charge monitoring with UHF method. The authors present a method for quantitative calculation of partial discharge of GIS by using Friis transmission equation. This method takes a partial discharge source as the transmitting anten-na model

the Friis transmission equation as the antenna transmission process

and the fourth-order Moore fractal antenna as the receiving antenna model. Hence

the relationship between the apparent discharge magnitude of GIS partial discharge and the energy with peak value of UHF signal is obtained. GIS partial discharge test verifies that the apparent discharge magnitude shows a quadratic relationship with the energy of the UHF signal

and shows a linear relationship with the peak voltage.