Responsive demand to mitigate slow recovery voltage sags

It is expected that in the future, customers will play a much more active role in modern power distribution systems. Instead of being passive agents, customers will be encouraged to participate in many other functions, such as frequency and voltage control, by providing a rapid, active, and reactive power reserve for peak load management through price responsive methods and also as energy providers through embedded generation technologies. This article introduces a new technology, called demand as voltage-controlled reserve, which can help mitigation of momentary voltage sags. The technology can be provided by thermostatically controlled loads as well as other types of load. This technology has proven to be effective in distribution systems with a large composition of induction motors, when voltage sags present slow recovery characteristics because of the deceleration of the motors during faults. This article presents detailed models, discussion, and simulation tests to demonstrate the technical viability and effectiveness of the demand as voltage-controlled reserve technology for mitigating voltage sags.