What is the typical sequence of operations for OCR's protected by fuses?

The sequence of operations for Oil Circuit Reclosers (OCRs) protected by fuses is designed to enhance safety and reliability during fault conditions. The correct answer involves a sequence of 2 fast operations followed by 2 slow operations.

In this context, the "fast" operations are quick attempts to restore service after detecting a temporary fault. If these fast operations fail to clear the fault, the OCR will enter a "slow" operation mode, which allows for extended time intervals before attempting to reclose. This combination is critical because it ensures that transient faults, which may resolve themselves quickly, can be addressed without unnecessarily interrupting service for prolonged periods. The additional slow attempts provide more time to allow for stabilization and to ensure that any persistent faults are properly mitigated.

The methodology of using multiple fast operations followed by a slower series strikes a balance between minimizing outages and preventing equipment damage, as well as ensuring safety for linemen and the equipment involved.