Possibility of Electric Arc Detection in Power Transformers by Directly Embedded Photoconductive Elements in the Transformer Tank (Limitations and Obstacles-An experimental investigation)

In this contribution an application of potential light sensitive semiconductive elements including photo resistors and photodiodes as electric arc detection sensors in the transformer tank is comprehensively investigated. Conventionally, a Buchholz-relay (BHR) is implemented for arc fault detection in power transformers. Unfortunately, in some cases the tripping of the transformer is not fast enough in order to prevent a tank rupture and the catastrophic collateral damages. Therefore an application of light sensitive elements as optical sensors are investigated, for detecting an arc inside a transformer tank faster under various operational conditions. This contribution focuses on the performance of sensors, which are inserted in the transformer tank. Apart from consideration of different factors such as stochastic nature of light in arc, thermal cycling, the distance effect on the light sensitivity and possibility of light reflection by the tank, challenges and limitations of arc sensing with light sensors in the mentioned approach are comprehensively discussed. The deficiencies and limitations of the arc sensors are revealed through the experimental investigations conducted.