On the use of Vivaldi antennas in the detection of partial discharges

Due to their impulsive nature, partial discharges in insulation systems emit in a broad band of frequencies ranging from tens of megahertz to gigahertz. Antennas can be placed at secure distances from the high-voltage source and measure partial discharges pulses on-line. The energy of partial discharges coexists with strong electromagnetic emissions such as frequency modulated radio, television broadcasting and mobile telephones. Then, the antennas should be tuned to detect the emission from partial discharges in bands where the electromagnetic noise is not so important. They should also be capable of receiving in a broad range of frequencies so resonant antennas should be avoided. Vivaldi antennas can be designed to detect emissions from a desired tuned frequency and extended to a band as wide as necessary. This makes them a valuable tool to detect partial discharges avoiding electromagnetic noise present at lower frequencies.