What are the two fast operations of an OCR primarily aimed at protecting?

Optical Current Relays (OCR) are designed to provide fast protection primarily for the line on the load side. This function is critical because any faults or disturbances occurring on the line can lead to serious operational issues, including equipment damage and outages. The OCR detects these anomalies quickly, allowing for rapid disconnection or other mitigation measures to be implemented, thereby minimizing risks to infrastructure and ensuring safety.

While OCRs do also play a role in protecting equipment such as generators, transformers, and main switches, their primary focus in fast operations is on the load side line. This prioritization is due to the potential for quick fault progression and the need for immediate action to maintain the stability and reliability of the overall electrical system. Protecting the line on the load side helps prevent further complications that could arise if faults are allowed to escalate.