ABSTRACT
The minimum excitation limiter (MEL) is unique in that it is not a protective relay, but rather a control function integral to the automatic voltage regulator (AVR) circuitry. It acts to limit Var flow into the generator. During normal operation, the AVR maintains generator voltage at a preset value. When system conditions attempt to produce Var flow into the generator in excess of the MEL setpoint, the MEL activates, overriding the AVR setpoint to increase terminal voltage which reduces the Var in-flow. The voltage increase continues until Var flow is reduced below the MEL setting.
