Relay protection is the discipline of designing schemes that detect faults, coordinate relays, and isolate equipment without outages. While this is bad, It's not a. The potential transformers (PTs) and current transformers (CTs) usually produce electrical signals which monitor the state of current and voltage in a system. CTs and PTs reduce the high currents and voltages of a power system to those levels which can be handled by a relay safely. It emphasizes selectivity, coordination, fault response, and system behavior rather than individual relay devices.