Under Voltage Protection Relay

Under voltage protection sense the phase to phase voltage of the generator transformer using instrument transformer potential transformer.

Under voltage protection relay.

Principle of under voltage protection. When voltage returns to in range the delay is not used and the relay indicates in range immediately. When the voltage drops below the rated voltage typically 85 stage 2 90 stage 1 the under voltage protection will be activated. This information is internally processed by the microprocessor to take the voltage protection.

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

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. As long as the monitored voltage remains below the maximum voltage the equipment can withstand the relay remains de energized and remains closed keeping the load energized. The voltage protection relay vpr a has been designed to measure the line or phase rms voltages under normal conditions or under disturbances.