Research On Voltage Security Cost In Optimal Operation Of Power System

Voltage Security Cost stems from the research of voltage stability constrained OPF (Optimal Power Flow) problems by Rosehart et al in Canada. They incorporate voltage stability indices into traditional OPF problem and propose several different voltage stability constrained OPF formulations, which gains the end of studying voltage stability and optimization problems simultaneously. But they only show aggregated operating costs obtained by different formulations using various weighting factors, and do not analyze and discuss thoroughly the voltage security cost because of the dependence on the weighting factors of the formulations. The unified dispatch and management keeps the secure and stable operation of power system in a vertically integrated environment. However, secure and stable operation of power system need the active maintenance of participants driven by economic interests in the power market. Therefore, with the change from vertically integrated environment to power market, the estimation of security cost and pricing security become very important. And the voltage security cost, as the additional expense of keeping system voltage security and stability, becomes one of the important problems on cost analysis and study in the power market.The optimization problems considering voltage security margin indices are thoroughly studied to overcome the deficiency of existing methods in evaluating voltage security cost in the thesis. Three optimization formulations are proposed to estimate voltage security cost and the costs obtained by those formulations are analyzed and discussed in detail. On this basis, the composition of voltage security cost in power market is analyzed according to the technical and economic characteristics of each market participant. The main contributions of the thesis can be summarized as:(1) A universal multi-objective OPF model considering ideal loading margin index is presented based on the Goal Programming formulation. The proposed model incorporates the square of the deviation of actual loading margin from ideal loading margin into the objective function, which reduces the uncertainty of results caused by...