Исследование позиционной модели энергетической системы

Abstract

The position model specific features are investigated; the eigenvalues and eigenvectors of the small perturbation equation matrix are analyzed, and a criterion of limiting operation modes in terms of aperiodic steady-state stability is obtained, which generalizes the classic Wagner - Evans criterion for complex multimachine systems. It has been found that the position model, i.e., a model in which the powers and torques of generators depend only on the relative angles of machine rotors, implicitly uses the distributed slack bus philosophy, and its limiting modes in terms of aperiodic steady-state stability are exactly identical with the limiting modes of a load flow model with a distributed slack bus in which the coefficients characterizing the participation of nodes in active power balancing are assigned to be directly proportional of the synchronous machines’ inertia constants. It has been found from a comparative analysis of the limiting mode parameters in the position model and the model with an infinite bus that the position model yields a conservative (underestimated) assessment of the electric power system steady-state stability margin. It is shown that the steady-state stability margins are estimated in the most adequate manner by means of the load flow model with an infinite bus, in the limiting modes of which the relative power loss increments do not exceed unity for all nodes.