The occurrence of Partial Discharge (PD) in the insulating systems of high voltage equipment is a symptom of fragility in dielectric withstanding, whose evolution can have serious consequences for these equipments and for the electrical system.
The detection of PD generated inside an insulating system is of fundamental importance in order to evaluate the existence of internal defects, since it is the technique that most prematurely can diagnose a future fall in electrical withstand voltage.
Traditionally, the Partial Discharges have been evaluated by the measurement of the high frequency electrical pulses conducted in a specific measurement circuit, according to the procedures described in the international standard IEC 60270, called electromagnetic method.
Depending on the intensity of the Partial Discharge, the life of the insulation system can be reduced dramatically. In addition, one of the purposes of the Partial Discharge test is to contribute to the determination of the relationship between the quantities that govern the Partial Discharge and the life expectancy of the associated equipment or, at best, to establish a minimum life expectancy before intervention is required.