Insulation diagnosis method for generator winding by measuring microwaves associated with dielectric breakdown
✍ Scribed by Masatake Kawada; Zen-Ichiro Kawasaki; Kenji Matsu-ura; Toshio Musashiya; Satoru Kuroki; Teruya Osawa; Hiroki Tanaka
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 237 KB
- Volume
- 132
- Category
- Article
- ISSN
- 0424-7760
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✦ Synopsis
Partial discharge (PD) within voids in a solid insulating system is a symptom and/or a direct cause of deterioration of a generator winding. It is reported that PD is a very short duration current and/or voltage pulse, about 1 to 5 ns. Generally PD emits an electromagnetic wave which is a broadband range signal (~ gigahertz). Therefore, we developed a new system for detecting the electromagnetic wave, especially microwaves (gigahertz) associated with a material defect of the winding. From the point of view of preventing accidents of insulation breakdown, it is important to assess the condition of the winding. We applied our system to a dielectric breakdown test to learn the relation between the characteristics of the microwaves 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 pulses and the amplitude of the microwaves per voltage cycle.