Distributed Algorithms for Voltage Control in Electrical Networks

This thesis proposes a method to utilize distributed energy resources to provide the reactive power support required to stabilize and control voltage in electric power systems. As the number of distributed energy resources continues to increase, traditional approaches to the design and control of distribution networks will no longer be adequate. For example, on a clear day with high incident irradiance, it is possible for the active power injections from photovoltaic systems to reverse the flow of power and cause over-voltages on certain buses. The impacts of photovoltaic systems and plug-in hybrid electric vehicles on distribution networks are of particular interest due to the potentially high penetration of these devices in the years to come. Although the contribution of each device is small, collectively, they can have a significant impact on system reliability and performance. Since the placement and number of these devices are unknown to system operators, a decentralized-distributed control strategy is desired to determine the reactive power support provided for ancillary services. This thesis presents a resource allocation algorithm and an adpative algorithm that modifies its behavior to respond to voltage limits on a radial line. The ability of these distributed algorithms to control voltages is illustrated in a series of case studies