| In this thesis the following issues related with electric power system and electricity market are researched. They are probabilistic optimal power flow, transfer capability and ancillary services, coherency identification, and large-scale power grid stability analysis. The main achievements are as follows:A three-point estimate method to solve the probabilistic optimal power flow for electricity market with uncertain factors was proposed in this paper. The high-order moments of stochastic variables to construct the estimate points and the certain relations between stochastic variables and objective function were utilized to determine the estimate value of objective function. By this method the probabilistic problems can be handled with same routines as those corresponding to deterministic problems while alleviating the computational burden. Probabilistic information obtained by this method is helpful to reveal the actual status in electricity market.From the point of economic theory view, the issue of pricing the services provided by Power System Stabilizers (PSS) to damp out low-frequency oscillations in large interconnected electrical power grids was proposed. Methods based on Shapley value and nucleolus in the cooperative game theory were utilized to determine the PSS impact on power system transfer capability and its contribution to power system dynamic stability. All of these give new concepts in evaluating the value of excitation control in electricity market , and provide Genco incentives to improve excitation control technology.An independent component analysis (ICA) based feature extraction method for analyzing perturbed trajectories of generators was proposed. Comparing with existing methods, generators'speed signal measured by WAMS can be utilized directly in new solution while detailed model and parameter of power system components were not needed. By this means high-order data of multi-machine perturbed trajectories were reduced to lower dimensions, and coherent generator groups were identified by pattern recognition consequently. This method is useful in electricity market environments because of it no need for generators'parameters.The problems of 750kV Northwest China power grid encountered in initial operating stage and corresponding solutions were proposed. The actually measured excitation system models and their parameters were led into annual power network stability calculation. Simulation results show that by use of such models and parameters the dynamic performance and stability level of Northwest China power grid is evidently improved. The transmission capability of Northwest China power grid can be raised considerably. Influence of operation modes of electro-magnetically coupled 750/330 kV power grid on system security and stability when Northwest China 750 kV main network preliminarily completed is also researched. The results of static security and stability analysis show that before a strong 750 kV network is built up, the operation mode of electro-magnetically coupled power grid, i.e., the close-loop operation mode, is available to enhance the transmission capacity and stability level of Northwest China power grid than open loop operation mode. The target of constructing Northwest China power grid was also proposed. It is pointed out that based on the wide area measurement system, on-line control schemes of controlled system splitting, stability control and low-frequency/low-voltage load-shedding should be studied immediately. Adaptive and coordinated control on Northwest China power grid can be achieved by establishing wide area control system. By these means, Northwest China power grid can keep secure and stable operation and healthy development.
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