Under Voltage Protection Relay

Three phase motors and other equipment are commonly used in a variety of industries.

Under voltage protection relay.

Geya under over voltage relay provides protection to equipment that cannot handle excess voltages. The under voltage setting is usually 80 percent of the normal operating voltage. When voltage returns to in range the delay is not used and the relay indicates in range immediately. The voltage protection relay vpr a has been designed to measure the line or phase rms voltages under normal conditions or under disturbances.

There is 1 0 to 1 5 v of hysteresis on the limit threshold settings to prevent oscillation and relay chatter when a voltage is at a low or high extreme right on the limit threshold. Under voltage protection sense the phase to phase voltage of the generator transformer using instrument transformer potential transformer. The time setting is used to avoid tripping due to any transient disturbances. If the voltage falls below this level for the set amount of time then the tripping command issued by the relay and hence the system is isolated.

Principle of under voltage protection. A three phase monitor relay with undervoltage protection can shutdown equipment when undervoltage occurs preventing damage. A clear indication of the fault present is provided by these relays for rapid troubleshooting and reduced downtime. This information is internally processed by the microprocessor to take the voltage protection.