ceire-263_md. moshiul alam_md. forhad zaman

Proceedings of the Conference on Engineering Research, Innovation and Education 2011 CERIE 2011, 11-13 January 2011, Sylhet, Bangladesh * Corresponding Author: Md. Moshiul Alam, E-mail: [email protected] SIMULATION OF TRANSIENT AND STEADY STATE CONDITIONS OF SYNCHRONOUS MACHINES FOR POWER SYSTEM Md. Moshiul Alam 1 * and Md. Forhad Zaman 2 Department of Electrical and Electronic Engineering 12 Rajshahi University of Engineering and Technology 12 , Rajshahi – 6204, Bangladesh Electrical power plays a vital role in modern life. Synchronous m achines are the he art of generation section of a power system. Power system engineer lar gely fo cuses on steady state analysis. But transient stability analysis has recently become a major issue in th e operation of power systems du e to the increasing stres s on power s ystem networks. This problem requires evaluation of a power system's ability to withstand disturbances while maintaining the quality of service (QOS). Computer based modeling and simulation of electrical machine has certainly opened new horizons for the performance analysis. A good mathematical model can help in predicting the behavior of an electrical machine under different operating conditions and in selecting the appropriate machine for a specific application. This paper presents a linear mathematical model of the synchronous generator with excitation system for power system stability. This paper also shows a method as an accurate algorithm to analyze transient and steady sta te stability for power system with an in dividual machine. It can be used as a tool to identify stable or unstable conditions of a power system after fault clearing with solving linear differential e q u a t i o n s . The transien t stabi lity will be shown graph icall y while th e stead y state s tabil ity will be examine d by Eige n values. MATLAB will be us ed for pro gramming. Key words: Synchronous Machine; Transient State; Steady State; Eigen Value; Simulation; QOS. 1. INTRODUCTION The stability problem is concerned with the behavior of the synchronous machines after they have been perturbed. Steady state refers to the ability of the power system to regain synchronism after small and slow disturbance, such as gradual power changes or transient fault of a power system. Transient state deals with the effects of large, sudden disturbances such as occurrence of a fault, the sudden outage of line or the sudden application or removal of loads. The problem of steady state as well as transient stability simulation can be considered as one of solving a system of algebraic equations together with a system of differential equations. The algebraic equations describe the steady state behaviour of the network, which includes loads and synchronous machines. The differential equations describe the dynamic behaviour of the machines and their associated control systems such as excitation system, prime mover governor system, turbines etc. This paper demonstrates the simulation of the steady state and transient response of synchronous machine connected to an infinite bus using MATLAB [7]. 2. MODEL SPECIFICATIONS Simulation of the transient response of any dynamical system represented by state variables requires initial conditions for those state variables. There are some assumptions made prior to the design of the simulation model. The output terminals of the generator are connected to infinite bus bar that has constant load as shown in Fig.1. The time constants of the synchronous machine and the system data used in this paper are assumed to be the optimum time constants [1]. Syn. Generator Inf inite Bus Fig. 1: Test Network

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