On-Line Network Topology Optimization For Increasing Static Stability Limit Of Large-Scale Power Systems

Of the controls of steady stability of power system, network topology control is a practical, easily implementing and low cost control. In this dissertation, the network topology optimization is firstly proposed to improve power system operation and an on-line network topology methodology is proposed to increase load margin to static stability limit of a look-ahead power system under on-line environments. A sensitivity-based method is employed to screen all the controls and those effective controls for the objective are remained; then a nonlinear estimated method is employed to estimate and rank those effective controls; finally a detailed computation method is employed to calculate the objective value and identify the most effective control. Distinguished features of the proposed methodology are summarized as follows.1) the original nonlinear model are considered in the proposed methodology which is not simplified;2) it is fast and is applicable on on-line environments;3) it can provide multiple network topologies at given a desired number of control actions from which operators can choose a desired one;4) it satisfies the operational and engineering constraints of the post-optimizated power system without the generation redispatch and load shedding;5) it is good robust.The impact of network topology on saddle-node bifurcation due to the inadequate of available transfer capability is studied in the dissertation. The controls of electric network topology optimization including line switching in/out and bus splitting can be used to increase the static stability of power system. Because numerous splitting scenarios are generated due to bus splitting, a novel bus splitting model is proposed in the dissertation. All the splitting scenarios can be model and generate by this model easily, and can be fast screened for on-line application.The impact of network topology on structure-induced bifurcation in power system is studied. A problem formulation for delaying structure-induced bifurcation is proposed and then the methodology for increasing the voltage stability of look-ahead power system via network topology optimization is proposed. The numerical studies show the change of network topology of power system can delay the occurrence of structure-induced bifurcation and increase the voltage stability.The impact of the uncertainty of renewable energy on static stability is studied. In this dissertation, the traditional scenarios reduction methods do not suitable for static stability analysis. A novel on-line network topology optimization considering renewable energy methodology is proposed for increasing static stability of power system.