Estimating the Effects of Small Voltage and Frequency Changes on Industrial Induction Motor Loading

This work develops expressions for estimating the change in active and reactive power for industrial motors in response to voltage and frequency variations around the operating point. Magnetizing circuit saturation is accounted for by using incremental reactance. The expressions are simplified for a quick estimate using stator measurements and parameters. The expressions are validated using simulation, and further, a test was carried out in a nuclear power plant to determine the voltage sensitivities experimentally. Both simulation and test show that the expressions are capable of yielding a fair estimation of the required sensitivities.