Rodney.Ferguson
Member
Problem detail:
We faulted on our main 480V 3800A switch gear for unbalanced load. C phase dropped from 484V to 250V. Our team dropped out all feeders from our main. We then went to 325V on C phase. Root cause C phase bayonet fuse of 120A on our 13KV line side of transfomer blew. Our load fuses were intact. Our main switch showed no fault other than unbalanced load.
Actions:
We immediatly turned all feeders off. (Lost a few fuses). Megged out all high HP motors. All good.
Secondary fuses on 2500KVA transformer; okay. Main feeder (13KV) to transformer; okay. The only fault was the Bayonet fuse on primary side of 2500KVA tranformer.
Question:
How? Power provider states it came from our side. We checked major power consumers and found no problems. After we powered everything back up without any repairs we have ran for 1 week with no futher problems.
Has anyone seen similar porblems? Could the power provider be at fault? If so, what data could be requested to find out?
Any help would be appreciated.
We faulted on our main 480V 3800A switch gear for unbalanced load. C phase dropped from 484V to 250V. Our team dropped out all feeders from our main. We then went to 325V on C phase. Root cause C phase bayonet fuse of 120A on our 13KV line side of transfomer blew. Our load fuses were intact. Our main switch showed no fault other than unbalanced load.
Actions:
We immediatly turned all feeders off. (Lost a few fuses). Megged out all high HP motors. All good.
Secondary fuses on 2500KVA transformer; okay. Main feeder (13KV) to transformer; okay. The only fault was the Bayonet fuse on primary side of 2500KVA tranformer.
Question:
How? Power provider states it came from our side. We checked major power consumers and found no problems. After we powered everything back up without any repairs we have ran for 1 week with no futher problems.
Has anyone seen similar porblems? Could the power provider be at fault? If so, what data could be requested to find out?
Any help would be appreciated.