Method for distinguishing stability of muilt-timelag electric power system

Abstract

The present invention belongs to the technical field of power system, and relates to a method of time-delay stability criterion. The method adopts the idea of Lyapunov stability criterion; an appropriate Lyapunov functional is selected at first, and is transformed into a group of linear matrix inequalities (LMI) for solution through the Leibniz-Newton formula, relaxation and other means; simultaneously, the redundant items which are generated in the deduction process is eliminated so as to acquire the stability criterion. In the method, the items to be calculated are greatly reduced, and the operating efficiency is correspondingly improved. Moreover, because the time-delay stage widely occurs in various systems, the method is suitable for various environments with the time delay.

Description

technical field The invention belongs to the technical field of power systems, and relates to a method for determining stability with time delay. Background technique Time lag widely exists in all aspects of the power system, but traditional control signals are mainly obtained from local measurement devices. Literature [3] mentioned that when the time lag is very small, it is usually not considered. However, in the case of wide-area control, the time-lag of the measurement link is very obvious, so it is of great practical significance to study the influence of the time-delay link on the stability of the power system. People have carried out research on the stability of time-delay dynamical systems very early. According to literature [4], it can be seen that the Smith prediction theory proposed in the 1950s can completely eliminate the known fixed time-delay in the system transfer function, thereby making it Simplify it into consideration for general systems; literature [2]...

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Problems solved by technology

Literature [11] reduced the conservatism of the method by adding loose items in the derivation process of the single-delay stability criterion, and achieved good results. Literature [12] extended it to multi-delay systems to form the so-called free weight matrix (Free Weighting Matrix) method, but due to the introduction of a large number of loose items, the calculation efficiency of the method is greatly affected

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