A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development

Thesis (Ph.D.) - Asian Institute of Technology, 2004

This dissertation proposes a coordinated fuzzy constrained optimal power dispatch (CFCOPD) algorithm for bilateral contract, balancing electricity and ancillary services markets. The CFCOPD problem is decomposed into social welfare fuzzy maximization subproblem which is solved by the mixed-integer fuzzy linear programming (MIFLP) and combined reactive power cost and cost of real power loss fuzzy minimization subproblem which is solved by the fuzzy linear programming (FLP). In the social welfare maximization subproblem, the framework includes three separate markets which are bilateral contract market (BCM), balancing market (BM), and ancillary services market (ASM). The proposed CFCOPD algorithm maximizes the overall social welfare in three markets simultaneously satisfying power balance, ancillary services requirements and line flow constraints. The line flow limit and transformer loading constraints and ancillary services requirements are treated by the fuzzy constraints. In the combined reactive power cost and cost of real power loss fuzzy minimization subproblem, the reactive power prices and quantities are offered by the ancillary services providers. The bus voltage magnitudes are also treated by the fuzzy constraints. The proposed CFCOPD algorithm is tested oil the modified IEEE 30 bus system and the Thai power 424 bus system. Tile dispatch results show that the social welfare of the fuzzy constrained competitive electricity and ancillary services price (CEASP) scheme with bilateral contract curtailment bids is higher than those of competitive electricity price (CEP) scheme, and CEASP scheme with and without bilateral contract curtailment bids, leading to a lower average electricity price. In addition, with the spot price including the marginal electricity price and marginal ancillary services prices, the sharper price signal could be sent to all market participants.