Circuit Breaker Tripping in Semiconductor Plant Caused by Voltage Dips

A semiconductor plant experienced a problem where the LV side main circuit breaker was tripped by voltage dips. As a result, power to all connected loads was interrupted and manufacturing processes were halted. The main cause of this problem was the unsuitable design of the under-voltage protection system. When a voltage dip occurred it was misinterpreted as an under-voltage event by the protection system, which erroneously tripped the circuit breaker. To solve this problem, a small uninterruptible power supply (UPS) was installed to maintain full power to the under-voltage relay and no-volt release coil of the circuit breaker in order to prevent erroneous tripping during a voltage dip.