Patent ID: 8762081

Claim:
A method for locating partial discharges occurring at a discharge site ( 2 ) in an electric apparatus ( 3 ) with elongate geometry and generating corresponding electric pulses ( 4 ) propagating in opposite directions along the apparatus ( 3 ) from the discharge site ( 2 ), the method comprising the following steps: detecting ( 11 ) the electric pulses ( 4 ) picked up by a first and a second sensor ( 5 , 7 ), operatively connected to the apparatus ( 3 ) in a first and a second detecting station ( 6 , 8 ) which are spaced out along the apparatus ( 3 ), and generating corresponding electric signals representative of the waveform of the pulses ( 4 ); selecting ( 12 ) at least one pair of signals, detected in the first and the second sensor ( 5 , 7 ), representative of a pair of homologous pulses ( 4 ), relating to the same partial discharge and propagating in opposite directions along the apparatus; deriving, for the signals of the selected pair of homologous pulses ( 4 ), at least one attenuation parameter, correlated with a quantity that is variable depending on a distance travelled by the pulses ( 4 ) from the discharge site ( 2 ) to the corresponding detecting station, said attenuation parameter including amplitude of the signal; calculating ( 13 ) the distance, along the apparatus ( 3 ), between the discharge site ( 2 ) and the detecting stations ( 6 , 8 ), based on processing the values of the attenuation parameter for the signals of the selected pair of homologous pulses ( 4 ), wherein said processing comprises the calculation of an algorithm which links the attenuation parameter value of one of the signals of the pair of homologous pulses to the attenuation parameter value of the other one of the signals of the pair of homologous pulses, as a function of the difference between the distances of the first and a second detecting station ( 6 , 8 ) with respect to the discharge site ( 2 ), whereby said algorithm expresses the attenuation of the pulses ( 4 ) due to their propagation through the electric apparatus ( 3 ) from the discharge site ( 2 ) to the detecting stations ( 6 , 8 ), wherein the amplitude attenuation of one of the signals of said pair of homologous pulses previously selected is compared to the amplitude attenuation of the other one of the signals of the same pair of homologous pulses, for calculating the distances of the discharge site ( 2 ) from the detecting stations.