The time setting is used to avoid tripping due to any transient disturbances.
Under voltage protection relay.
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.
A three phase monitor relay with undervoltage protection can shutdown equipment when undervoltage occurs preventing damage.
The voltage protection relay vpr a has been designed to measure the line or phase rms voltages under normal conditions or under disturbances.
When the voltage drops below the rated voltage typically 85 stage 2 90 stage 1 the under voltage protection will be activated.
Under voltage protection sense the phase to phase voltage of the generator transformer using instrument transformer potential transformer.
The under voltage setting is usually 80 percent of the normal operating voltage.
This information is internally processed by the microprocessor to take the voltage protection.
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.
Geya under over voltage relay provides protection to equipment that cannot handle excess voltages.
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.
Three phase motors and other equipment are commonly used in a variety of industries.
When voltage returns to in range the delay is not used and the relay indicates in range immediately.