PRACTICAL APPROACHES TO SUPPLEMENTARY STABILIZING FROM ACCELERATING POWER.

A practical approach is presented to derive stabilizing action approximating that which would be ideally realizable from measured accelerating power. This approach derives all necessary information from terminal voltage and current of a generating unit as available from potential and current transformers. The method employs a watt transducer measuring electrical power output and a frequency transducer connected to measure the frequency of a voltage synthesized from terminal voltage and current to emulate a voltage whose phase angle follows the machine rotor angle. Accelerating power is preferred as an input signal relative to a speed signal because it requires 90 degree less phaselead than the speed signal. Noise problems are greatly reduced. A functional hardware implementation scheme of this idea is presented making it possible to apply stabilization to any generating unit in the form of a self-standing device modulating the voltage feedback into voltage regulators at the 115 ac level, the standard nominal voltage of potential transformers.