Research On Maintenance Scheduling For Generating Units In Electricity Market Environment

Worldwide restructuring of the power industry has brought new opportunities and, at the same time, imposed new challenges upon power system operation and management. Generation sectors are separated from the transmission sector and as a result generation companies are formed as independent entities. The revenue of a generation company depends on its energy supply as well as the market price. Building a reasonable maintenance scheduling has become one of the most important strategies for generation companies to maximize profits. The traditional approach of generation maintenance scheduling employed by the system operator through a centralized optimization method is no longer acceptable by generation companies and does not match with the electricity market operation mechanism. New methods must be developed for this purpose. However, to the best of our knowledge, no systematic research work has been reported up to now around the globe.Given this background, the problem of maintenance scheduling for generating units in the electricity market environment has been investigated systemically in this thesis. The problem of appropriately arranging maintenance scheduling can be divided into two stages in the deregulated environment, i.e., each generation company first develops its maintenance scheduling individually, and then submits to the ISO for reliability and security checking. The ISO must coordinate or regulate the maintenance scheduling submitted by generation companies whenever necessary. The thesis hereby is divided into two parts. The problem of developing optimal maintenance strategies for generation companies is addressed in the first part including chapter two to chapter four, and the regulation mechanism for maintenance scheduling as well as the allocation of willingness-to-pay are presented in part 2 with chapter five and chapter six included. The major contributions of this thesis are detailed as follows.First, a new methodological framework is developed for investigating the optimal strategies of maintenance scheduling for generating units with risk well taken into account, based on the widely employed power pool mode and the uniform clearing price. Two scenarios are examined in detail, i.e., for the two cases that the generation company studied is/is not a price taker in the electricity market operation. Based on the electricity market clearing prices estimated, a new methodological framework is presented, mathematical models formulated and a solving method developed. Finally, sample examples are served for demonstration.Secondly, based on the estimated market clearing prices of electricity an effort is made to investigate the optimal strategies of maintenance scheduling for generating units with risk management, under the methodological framework of the well-developed chance constrained programming. This approach provides an explicit manner for risk management by setting a required confidence level of revenue loss minimization.Thirdly, a model of optimal maintenance strategies is presented based on the estimation of maintenance scheduling of other generation companies. The relationship between the market clearing price and generation capacity adequacy is represented as a nonlinear function. Based on the loadsforecasted and the estimated maintenance schedules of generation companies, the market clearing price can be obtained. Then, the mathematical model of the optimal maintenance strategies is developed in the framework of the chance-constrained programming and a Monte Carlo based method presented.Fourthly, a new market mechanism is developed for regulating or coordinating the maintenance scheduling proposed by individual generation companies so as to maintain the security and reliability of the power system studied, while at the same time, to guarantee the fairness among all generation companies involved. This is achieved by requiring generation companies to submit both their maintenance schedules and their willingness-to-pay for keeping their maintenance schedules not being adjust...