The Effects of Distribution Voltage Reduction on Power and Energy Consumption

Voltage reduction is a practice which has long been used by electric power companies during emergencies to reduce peak demand. Since 1973, some have suggested that it can also be an effective energy conservation method. Others disagree. The purposes of this paper are to: 1) present what is known about the effects of voltage reductions on real power, reactive power, and energy, for individual and composite loads; 2) discuss the problems associated with conservation voltage reduction proposals; and 3) suggest promising approaches for further study. Tests were conducted to determine the real and reactive power dependencies on voltage of a three-phase 5 hp induction motor. The following conclusions are derived from the information presented in this paper. 1) Appliances, motors, and feeders generally show initial reductions of power consumption at reduced voltage, but little reliable information concerning energy exists. 2) Because of the lack of hard evidence and the problems associated with conservation voltage reduction programs, it would be premature for any regulatory agency to mandate such programs at the present time.