Analysis on Electromechanical Disturbance Propagation in a Finite Length Uniform Chain Discrete Power System

In this paper, based on a finite length uniform chain discrete power system, the reflection characteristics of electromechanical disturbance propagation are studied after the machine internal impedance is neglected. Utilizing the Laplace transform, the analytical expressions of the machine rotor´s angle increments and power increments at all buses are derived under the impacts of disturbance with the form of a unit-impulse function and a unit-step one. At the same time, the reflection formula of electromechanical disturbance propagation in the discrete model is also presented, as is the same as that of electromechanical wave propagation in the continuum model. All of these above show that the electromechanical dynamics of power system could be represented by the multiple superpositions of the reflections process of electromechanical disturbance propagation. Finally, the conclusions presented in this paper are validated through a simulation case, which have some theoretical meanings for understanding the time-space distribution characteristics of large-scale power systems´ frequency and to some extent revealing the internal mechanisms of electromechanical dynamic phenomena.