Patent ID: 7183774

Claim:
Method of detecting partial discharges in an electrical appliance, insulated in a receptacle, by means of an UHF antenna placed in this receptacle, comprising an analysis of a spectrum (RS 1 ) of an electromagnetic signal picked up by the antenna and of an identification of several frequencies of interest (B 1 , B 2 ) in the spectrum, for each of which the signal has an amplitude that is greater than a predetermined threshold value, whereby, to identify frequencies of interest, a comparison of the spectrum of the signal received by the antenna is made with a reference spectrum (RS 2 ) representing electromagnetic noise devoid of any signal coming from the partial discharges, as follows: for several predefined frequency intervals in the two spectra (RS 1 , RS 2 ), a calculation of a characteristic value of each interval is made, a comparison is made, interval by interval, of the characteristic values of the two spectra (RS 1 , RS 2 ), known frequencies (fc) of known electromagnetic noise are taken into account when comparing the spectrum of the signal received by the antenna with the reference spectrum, and the probability distribution of the amplitude of the spectrum (RS 1 ) of the signal received is taken into account, at a given frequency.