GE Multilin 489 Generator Protection System SR Series Relays Applications

Applications

- Synchronous or induction generators operating at 25Hz, 50Hz or 60Hz

- Primary or backup protection in cogeneration applications

Protection and control

The 489 generator protection system provides comprehensive protection,

metering and monitoring functions for small and medium-sized synchronous or

induction generators operating at 25. 50 or 60 Hz.

The 489 is ideal for primary or standby generator protection as well as cogeneration applications.

The 489's protection features include:

Generator stator differential

The 489 uses high speed dual slope differential protection to detect and clear stator phase faults.

Stator phase faults. Advanced CT saturation detection algorithms provide

additional supervision through the use of directional checks that

ensures that the fault occurs inside the generator before triggering a trip,

thus maintaining immunity to saturation that may be caused by external disturbances.

100% Stator Ground

100% stator ground fault protection is provided by an overvoltage element and an

adaptive differential voltage function that responds to third harmonic imbalances at the machine terminals and neutral.

The 489 will compare the machine neutral voltage with the grounding

current to determine if the ground fault is internal or external to the generator.

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.