Partial discharge signal detection using ultra high frequency method in high voltage power equipments: a review

Partial discharge (PD) can be detected using ultra high frequency (UHF) method to increase the detection threshold and to improve the performance of on-line measurement of PD in noise environment. The PD emitted energy as electromagnetic emission, acoustic emission and ozone and nitrous oxide gases. We can use this emitted energy to detected PD signal. The best method to detect PD in gas insulate substation, power cable and transformer is by using UHF electromagnetic wave. UHF method have advantages such as high sensitivity, a good signal –tonoise ratio (SNR). On the other hand, there are still some issues to be solved in the UHF methods, such as a clear understanding of the propagation characteristics of electromagnetic waves arising from the structure of the equipment, optimization of antenna design and calibration of charge. Furthermore, in on-site measurements and laboratory experiments it has been that UHF method gives avery moderate signal attenuations. In this paper, a review on UHF PD sensor connected at extra high voltage-termination of cables, UHF PD signals in a 132 kV gas insulated substation (GIS) transformer are described. Results from the measurement show that this method can give the precise value of PD signal.