Reassessment of voltage variation for load power and energy demand management

Voltage reduction had been used as an old strategy to decrease the power absorbed by aggregate loads with possible energy savings. In literature, it is possible to find works where it is reported that reducing voltage at load terminal, power reduction and/or energy saving can be obtained, even if often the power and energy reduction are analyzed mostly considering the aggregated loads behavior. Hence, the contribution of each single load is not well distinguished. Several old and recent studies have been conducted mainly on aggregated load-power behavior and -energy absorption and the results are often contradictory. The main reason for this disagreement is due to the new technologies and evolution on loads that has changed the load-power behavior and -energy absorption during the time. Therefore, it is necessary to reconsider this optimization technique, in particular, for both Distributed System Operators (DSOs) and end users in order to manage their, public or private, network load profile and energy consumption. This article provides experimental study and analysis on different load types’ behavior including more recent lighting type (especially LED systems) and some thermal loads versus voltage variation. The aim is to investigate voltage variation effects on active power, apparent power and energy consumption trend for different kind of load types. The results of this study revealed that, in the examined load types, adopting a voltage reduction strategy, even if in some cases an amount of active power reduction can be obtained, the energy saving is always negligible.