What is the primary function of protective relays in electrical systems?

Protective relays play a critical role in ensuring the safety and reliability of electrical systems. Their primary function is to detect abnormal conditions, such as faults, overloads, or short circuits, within the electrical network. When these anomalies are identified, protective relays are designed to initiate circuit isolation, effectively disconnecting the affected part of the system to prevent further damage or hazards. This automatic response helps maintain overall system integrity and protects both equipment and personnel from potential dangers associated with electrical faults.

The other options relate to important aspects of electrical systems but do not encapsulate the main purpose of protective relays. For instance, enhancing system power factor or regulating voltage levels pertains to improving system efficiency and stability, while measuring current flow accurately deals with metering and monitoring rather than protection. Therefore, the focus on detecting abnormal conditions and facilitating circuit isolation highlights the essential safety function that protective relays serve in electrical systems.