Online Detection And Correction of Inter Turn Faults in Transformers

Abstract

Mineral oil in the transformer acts as a coolant, as an insulator and also helps in detecting some of the faults. Using dissolved gas analysis (DGA) technique some of the transformer faults can be detected, based upon the compositions of gases present in the transformer oil. The severity of Interturn Fault (ITF) can be found by using a search coil. The location of ITF can be detected by placing the search coil over the limbs. Room temperature vulcanizing (RTV) silicones are available in the form of paste and are high temperature sealants. RTV sealant is applied after each layer of transformer winding. Whenever the ITF occurs, RTV sealant will directly apply on the hotspot, reduce the fault temperature to normal working condition and repair the winding insulation so that the transformer can continue to work even after the fault occurrence. This paper presents DGA technique to identify the transformer ITF, estimate severity and location of ITF using search coil, and mitigate the faults in the live condition using RTV paste.