Abstract
Partial Discharge (PD) within voids in solid insulating system is a symptom and/or a direct cause of a deterioration of a generator winding. It is reported that PD is a very short duration current and/or voltage pulse, about 1-5 [ns]. Generally PD emits electromagnetic wave which is a broadband range signal (_??_ GHz). Therefore we developed a new system for detecting the electromagnetic wave, especially microwave (GHz) associated with a material defect of the winding. From the point of view of protecting an accident of the insulation breakdown, it is important to assess the condition of the winding. We applied our system to a dielectric breakdown test to know the relation between the characteristics of the microwave and the insulation condition of the winding. The dielectric breakdown test is believed to be useful for estimating the minimum breakdown voltage which is a criterion of the insulation condition of the winding. Experimental results showed that this system was able to assess the insulation condition by measuring the number of the pulse and the amplitude of the microwave per voltage cycle.
