Single-phase voltage monitoring relay PNM-10

A network voltage monitoring relay (in English, "network voltage relay") is an electronic device used to monitor voltage levels in an electrical network and to trigger certain actions if the voltage levels exceed certain limits preset.

The mains voltage monitoring relay can be used to detect sudden drops or rises in voltage, which may indicate a problem in the mains, such as an overload or equipment failure. It can trigger certain actions, such as automatically disconnecting loads, to protect equipment and prevent power outages.

The mains voltage monitoring relay can also be used to monitor the supply voltages of sensitive equipment such as computers and other electronic devices. If the voltage drops below or above the set limit, the relay can trigger some protective actions, such as shutting down the computer to prevent malfunctions.

Voltage monitoring relays can be used in both single-phase and three-phase systems. In general, single-phase voltage monitoring relays are designed to monitor the voltage of a single phase, while three-phase voltage monitoring relays monitor the voltage on each phase of a three-phase system.

Among the most common types of single-phase voltage monitoring relays are:

Under-voltage relays - These are designed to monitor the voltage of a single phase and trigger an alarm or action signal if the voltage drops below a certain limit.

Over-voltage relays - These are designed to monitor the voltage of a single phase and trigger an alarm or action signal if the voltage exceeds a certain limit.

Secondary voltage monitoring relays (secondary voltage relay) - These are designed to monitor the voltage at the secondary of a transformer and to trigger an alarm or action signal if the voltage exceeds or falls below a certain limit.

In the case of three-phase voltage monitoring relays, the most common types include:

Phase voltage relays - These are designed to monitor the voltage on each phase of a three-phase system and to trigger an alarm or action signal if there is an imbalance or zero voltage in one of the phases .

Sequence voltage relays - These are designed to monitor the phase sequence of the voltage in a three-phase system and to trigger an alarm or action signal if the sequence is reversed.

Unbalance voltage relays - These are designed to monitor the voltage on each phase of a three-phase system and to trigger an alarm or action signal if there is a significant asymmetry between the phase voltages.

In general, the use of voltage monitoring relays is important to ensure the safe and reliable operation of electrical systems.