What is the primary purpose of an impedance relay in electrical systems?

The primary purpose of an impedance relay in electrical systems is to detect faults based on circuit impedance. Impedance relays measure the impedance along a transmission line or in an electrical system to determine whether there is a fault, such as a short circuit. During normal operating conditions, the impedance remains within a specified range. However, when a fault occurs, the impedance value will change significantly—usually decreasing for a short circuit.

These relays operate by comparing the measured impedance to predetermined settings. When the impedance drops below a certain threshold indicative of a fault condition, the relay activates protective mechanisms, such as disconnecting the faulty section of the circuit. This is critical for protecting equipment and ensuring the safety and reliability of the electrical system.

In contrast, improving energy efficiency, regulating voltage levels, and monitoring power quality are important aspects of electrical systems but are not directly associated with the function of impedance relays, which specifically focus on fault detection through impedance measurement.