ABB voltage monitoring relays are specifically designed to detect overvoltage and undervoltage and trigger a switch to turn off the circuit when a fault occurs. Voltage monitoring relays also detect voltage-related issues such as phase loss, phase imbalances and phase sequence. ABB's range of voltage monitoring relays includes devices that monitor a range of voltages, meaning you can select the correct device to suit the circuit that you want it to monitor. The range includes both single-phase and three-phase systems.
A voltage monitoring relay is a voltage protection device that de-energises equipment as soon as voltage changes and is outside of safe levels. The purpose of a voltage monitoring relay is to protect against voltage abnormalities, rather than to regulate voltage.