In the power system stability problems the primary actors in the mathematical system model are the differential equations defining the dynamic state variables of generation and load. These differential equations are coupled together by load flow equations. Mathematically the load flow equations are nonlinear algebraic equations. These differential equations and nonlinear algebraic equations form the mathematical Differential Algebraic Equations (DAE) model for the power system. The fuzzy set theory is commonly used in analysis of dynamical nonlinear systems. In this paper, we build a set of local dynamical fuzzy logic models for the differential equations, thus transforming the differential equations into nonlinear algebraic equations, the DAE into nonlinear algebraic equations. We try to simulate the system by solving the nonlinear algebraic equations rather than by solving the DAE model. We also compare the application of two types of dynamical fuzzy models: the discrete-time model and discrete-event model in this approach. First we explain the approach by a small DAE example, and then we apply it to a 10-bus power system.

Meeting Name

2004 IEEE Power Engineering Society General Meeting (2004: Jun. 6-10, Denver, CO)


Electrical and Computer Engineering


National Science Foundation (U.S.)


This work was supported in part by the U.S. National Science Foundation under Grant ECS-9975713

Keywords and Phrases

Fuzzy Set Theory; Nonlinear Dynamical Systems; Nonlinear Equations; Power System Interconnection; Power System Stability; Differential-algebraic equations; Fuzzy logic; Mathematical analysis

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2004 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jun 2004