Study of voluntary demand side load shift (VDSLS) and direct load control (DLC) for restructured power systems

Abstract

Electric power utilities around the world have been experiencing restructuring since the 1980s. The objectives of power system restructuring are to introduce competition in the electric power industry and to provide more choices to market participants in the way they trade electricity and ancillary services. The direct consequence of the restructuring is the separation of the conventional vertically integrated utilities into independent generation, transmission and distribution companies. Economic segregation and service unbundling have changed the mechanism of conventional system planning and operation. The expected benefits of power system restructuring are cheaper electricity through competition and innovation, and improved generation and planning efficiency and economies. However, the restructuring of power systems has been accompanied by some problems, including capacity shortage, transmission congestion, price volatility, and reduced system reliability. Load management has re-emerged as an important element in fine-tuning the reliability and price in restructured power systems. Load management, as defined by IEEE's Demand-Side Management Subcommittee, constitutes activities that influence load shape of power systems so as to accomplish peak clipping, valley filling or load shifting which includes everything from direct control of small customer end users to voluntary load shifting by large commercial/industrial customers. By reshaping the system load curve and shaving the system peak load, load management can improve the system reliability and reduce the price volatility of restructured power systems. Load management faces new challenges due to the problems accompanying restructuring of power systems. The existing load management techniques have to be improved to face these challenges. The issues of load management have been studied in this thesis in order to make load management more successful in the new environment. These include the correlation between electricity prices and demands; the effects of the resulting voluntary demand side load shift on system reliability and electricity price volatility; the impact of II