Strategies Of Power System Transient Stability Control Based On Interior Point Method Optimal Power Flow

Security-stability and economics are the two topics for the power system operation and management. However, these two problems have been studied separately for long time, the work that how to coordinating the two topics were begun only few years ago. The work of this dissertation is aim to establishing the mathematical model of the coordination of the power system security-stability and economics and, at the same time, look for an effective algorithm to solve them.Interior point method is a main-stream method in the mathematical optimization areas. On the basis of nonlinear Predictor-Corrector (PC) and Multiple-Centrality-Correction (MCC) interior point method, an improved nonlinear predictor-corrector interior point method was proposed in this dissertation. A hypercube projection technology which has been applied in MCC is introduced to the correction stage of the proposed method. Improving the structure of projection space by setting some key parameters rationally to make the method get good iteration step lengths only by one correction calculation. So the method can converge to the optimal solution rapidly. The numerical performance of the proposed method is evaluated on seven power systems ranging in size from 5 buses to 118 buses. Computational results demonstrate that this technique is fast and robust, its iteration times is equal to the MCC with four centrality-correction every iteration. Several implementation issues such as the determination of convergence criteria and the choice of initial points are also addresses in detail.The formulation of power system transient stability preventive control based on optimal power flow is presents in this thesis, in which multicontingency is considered. The infinite dimensions nonlinear optimization problem in which differential-algebraic equations are existed is changing into finite dimensions difference-algebraic equations by implicit trapezoid method. At the same time, an effective technique is introdued to filter out the binding contingencies so as to reduce the scale of the optimization problem and can be solve by the improved nonlinear predictor-corrector interior point method. Case studies are carried out on a 4-machine 11-note and New England 10-machine 39-note system respectively. Numerical simulation results demonstrate that the formulation and the algorithm are suit for on-line operation. Some key factor such as maximum rotor angel value and clearing time are also discussing intensively in this thesis.The mechanism of the inter-complementarity of preventive control and emergency control is interpreted. And then, the formulation of the coordination of preventive control and emergency control, namely, hybrid control is developed, that is, multiobjective nonlinear mixed integer programming. The formulation is changing into a conventional static-state optimal power flow problem by handle the multiobjective programming problem and the mixed integer programming problem simply. Finally, the problem can be solving by the improved nonlinear predictor-corrector method, simulations on New England 10-machine 39-note system highlight its excellent performance.