Multi-Machine Power System Excitation And Generalized Hamilton Realization Control Method And Application

In order to guarantee the safe, stable and economical operation, the main effective method to improve the stability of power system is controlling besides adopting reasonable programming, construction and urgent measurements for the power grid. Power system is a typical strong nonlinear, high dimension dynamic system, while the excitation system of generator is always one of the most economical and effective methods to improve the power system stability. Because it is difficult for linearization controlling method to satisfy the controlling requirements of the power system when the operation point of the system changes, it is necessary to design the excitation controller with nonlinear control theory.With the structure preserving model of multi-machine power system and nonlinear load model which is relative to bus voltages, the system is firstly presented as a nonlinear differential algebraic system in this paper. Under the two conditions of not considering transfer conductances and considering self-admittances and mutual susceptances, corresponding generalized Hamiltonian realization approaches of the nonlinear differential algebraic system is proposed based on the generalized Hamiltonian system theory and the related nonlinear stabilizing controller design method for the dynamic system is presented. Particularly, under the latter condition, self-admittances and mutual susceptances are taken into account and remained in both algebraic equations and Hamilton energy function (mutual conductances are surpposed to be very small and considered to be zero here). In this way, the control strategy is more confirmative to actual situation.Finally, the view point of complex networks being introduced, the dynamic characteristics of power grid is analyzed and studied to illustrate the its characteristics that adapt to the common characteristics of complex networks. Combining with generalized Hamiltonian theory, the nonlinear differential algebraic model of multi-machine power system is constructed, which represents the random connection state of transmission lines.The difficulties to directly construct Lyapunov function in ordinary systems are avoided by using Hamilton energy function theory. Any geometrical linearization method wasn't used during the process of designing the control method and the nonlinear characteristics of dynamic system are completely reserved. Simulation of a two-machine power system illustrates the application of the controller design method and demonstrates the practicality of the controlling strategy proposed in this paper. Furthermore, compared with PSS excitation control method, the proposed controlling strategy can improve the transient stability of the power system more effectively.