usman74
Electrical
- Dec 7, 2014
- 14
hello ENGINEERS
i have some query about protection breakers.
two days ago, in plant during normal operation, one of the load at 380V bus (heater) shorted. heater has MCB for its protection. that 380V bus is fed from 6.3KV through step down transformer. that transformer has breaker at both primary & secondary side. breaker hierarchy is as follows:
MCB for load, T/F secondary side breaker above the 380V bus, T/F Primary side breaker below 6.3KV bus. when this short circuit happened, it causes to operate T/F primary side breaker and 380V bus lost eventually & supply to all other loads have been lost. while MCB and T/F secondary side remain intact. my question is that why this fault propagates, why not other two breaker operates.
i have some query about protection breakers.
two days ago, in plant during normal operation, one of the load at 380V bus (heater) shorted. heater has MCB for its protection. that 380V bus is fed from 6.3KV through step down transformer. that transformer has breaker at both primary & secondary side. breaker hierarchy is as follows:
MCB for load, T/F secondary side breaker above the 380V bus, T/F Primary side breaker below 6.3KV bus. when this short circuit happened, it causes to operate T/F primary side breaker and 380V bus lost eventually & supply to all other loads have been lost. while MCB and T/F secondary side remain intact. my question is that why this fault propagates, why not other two breaker operates.