Preventing Transformer Explosions with Fast Arc Detection by Fiber Optic Sensors

The adverse effects of transformer faults are manifold, including transformer explosions and fires that can result in significant financial losses, environmental damages, and physical harm or even fatalities. Therefore, Buchholz relays (BHR) are widely employed in power transformers to detect main faults in order to prevent tank ruptures. However, in some circumstances, BHRs may not trip quickly enough to prevent the aforementioned damages once an arc occurs in the transformer tank. In this regard, this investigation aims to develop a new system for fast arc detection, before increasing the internal pressure inside the tank. Fiber optic cables are used to design a novel sensor capable of detecting visible light emitted by an arc. In this paper, initially, the sensor is introduced and its performance is explained in detail using simulation, and then it is experimentally tested in different circumstances, including mineral oils, temperature variations, reflecting housing, and arc energy. Based on the results, the sensor recognized the fault at different temperatures as well as in mineral oil, and also reflections inside the transformer improve considerably the signal received by the sensor. A quick detection of arcs can be achieved with this method and this sensor is well compatible for use inside transformers.