Alternate Phase Distance

Two independent phase distance elements provide time-delayed backup protection

for generator faults that are not cleared by the main system and generator protection.

This distance characteristic compensates for unit delta/shunt power transformers

located between the generator and the end of the protection zone.

Sensitive Directional Power

The 489 provides low forward and reverse power elements to prevent generator

movement from damaging the prime mover.

Each element has separate power pickup level and operating delay settings for alarms and trips.

Circuit Breaker Faults

The embedded circuit breaker fault feature in the 489 improves system reliability

without the additional cost of providing a separate circuit breaker fault relay.

When a circuit breaker fault is detected, the 489 can be configured to operate

one of its four available digital outputs to signal upstream equipment to quickly isolate the fault.