The protection system also ensures reliability by localizing and isolating the fault and minimizing its impact on the rest of the power system.
The requirements of a power system are as follows
1. To isolate the equipment or component in which the fault has occurred. The isolation should be quick enough to prevent damage to the component itself. For instance, a short circuit inside can severely damage a transformer. The differential relay, in such a situation, should immediately act and trip the transformer.
2. To isolate the smallest possible section of the power system to minimize the interruption.
3. To prevent disturbance or disruption to other parts of the power system. The fault, if not isolated in time, can cause the upstream breakers to trip.
A well-designed protection system will greatly increase the reliability and performance of a power system.