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How To Set The Operating Time Of The Relay? |
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Answer» Naturally when a fault occurs it is sensed by both the primary and backup PROTECTION. As the operating time of primary relay is less than that of the backup relay, it will operate first. There will be an overshoot time (due to MOMENT of inertia of moving relay system). CONSIDER a primary relay A having operating time of 0.1 sec. Assume circuit breaker operating time as 0.5 sec and overshoot time as 0.4 sec. Now the operating time of backup relay B will be 0.1+0.5+0.4= 1 sec. Naturally when a fault occurs it is sensed by both the primary and backup protection. As the operating time of primary relay is less than that of the backup relay, it will operate first. There will be an overshoot time (due to moment of inertia of moving relay system). Consider a primary relay A having operating time of 0.1 sec. Assume circuit breaker operating time as 0.5 sec and overshoot time as 0.4 sec. Now the operating time of backup relay B will be 0.1+0.5+0.4= 1 sec. |
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