Which type of relay is specifically designed to operate when the current exceeds a predetermined level?

An overcurrent relay is specifically designed to operate when the current flowing through a circuit exceeds a predetermined level. This type of relay continuously monitors the current and activates if it surpasses the set threshold, which is crucial for protecting electrical circuits from overload conditions. By doing so, it helps prevent damage to equipment and maintains system integrity by disconnecting the affected part of the system when necessary.

Ground fault relays are tailored to detect fault currents that could arise when there is an abnormal condition, such as current leakage to the ground. Voltage relays, on the other hand, monitor voltage levels rather than current, activating when voltage goes above or below set levels. Distance relays are used primarily in transmission lines to determine the distance to a fault based on impedance, not directly based on the magnitude of current. Each of these relays serves a specific function, but the distinguishing feature of an overcurrent relay is its direct response to current exceeding a predefined limit.