| Title |
Deterioration Diagnosis of Epoxy Mold - type Transformer Using Ultrasonic Waves |
| Authors |
이상우 ; 김인식 ; 이동인 ; 이광식 ; 이동희 |
| Abstract |
Measurements of ultrasonic signals caused by partial discharges were performed by using an ultrasonic measurement technique to diagnose the electrical treeing deterioration in an epoxy mold-type power transformer. We also examined the characteristics of tree growth, partial discharge magnitude and ultrasonic pulse number with the increase of the deterioration time. From these results, it was found that the shape of the tree was a branch-type, and the rates of the tree growth were examined when ac voltages of 16[kV] and 20[kV] were applied. Ultrasonic pulse number and discharge magnitude were rapidly increased as the length of the tree grows after the middle stage of the deterioration time, and it appeared that ultrasonic pulse number was proportional to discharge magnitude. Attenuation, time-delaying and directivity characteristics of ultrasonic signals propagated into epoxy resin by using ultrasonic oscillation and receiving systems are also report as a basic data of ultrasonic measurements in mold-type power transformer. |