Fourier analysis for detection of corona discharge and high voltage discharges across insulators of HV lines

The Israeli electricity company in collaboration with Rafael performed measurements in the frequency and time domain of HV discharge from 161 kV and 400 kV voltage lines. By measuring the EM fields in time domain and performing a Fourier transformation that converts measurement results into frequency domain one can uncover information "hiding" in the measurements results that are unavailable otherwise. As this paper demonstrates, this measurement technique and the subsequent analysis can uncover and expose the nature of the high voltage (HV) discharges that occur in HV lines, both permanent such as corona discharges and occasional, such as the discharge of electrical charges across insulators that are caused by pollution and humidity.