We are facing problem of frequent tripping in Unit Station Transformer -2 during heavy rain. During checking, not found any abnormalities.
1.Fault UST2 OTI Trip Observation- * Direct OTI trip initiated without Alarm
* Oil temperature is normal
* Tripping contacts are not physically operated
* OTI trip contacts are operated frequently as per in Disturbance record Action taken-Spare Core of another cable used for OTI Trip contact
2. UST2 PRD Trip
* PRV contacts are not physically operated
* PRV trip contacts are operated frequently as per in Disturbance record New cable used for all contacts