Improved model for investigating transient stability in multimachine power systems

Abstract

<span>The determinant factor in transient stability study of electric power systems is the behavior of synchronous generators when subjected to sudden and large disturbances. The objective of this paper is to develop a mathematical model, general algorithm, and a computer program to investigate the transient stability of multi-machine power systems. The developed mathematical model is established as a first step. The new developments lie in modeling the fault occurrence and fault clearance as well as the procedure of computing the system matrices during and after the fault through only modification of the matrix before the fault. Based on the developed mathematical model, a general algorithm was built and translated into a computer program using an object-oriented and visual language called Delphi. The algorithm adopted the Runge-Kutta method for numerical solution of differential swing equations and was programmed within the program. The developed program was validated by applying it to small sample electrical networks. The program was used to analyze the transient stability of a relatively large test network and accurate results were obtained that could be relied upon for protective relays settings and optimization of control system parameters. It was found that the developed program is an effective and rapid tool for estimating transitory stability for real power systems.</span>

Implementation of graphical user interface to observe and examine the frequency and rotor angle stability of a power system due to small disturbances

“…(1) (6), both values are then inserted into (3). H is a constant where it is set to 9.92. d) Calculate the value of the phase angle theta, θ from (7) and the value of damping ratio, z using (8). e) Determine the value of damping ratio, z where D is the angle of disturbance inserted by the user.…”

“…The time, t is set from 0 second to 3 minutes using a 0.01s interval. f) Determine the value of P s from (8) to be inserted into (6), (7) and (8).…”

“…c. After that, determine the initial angle in radian, Dd0 using (4). Determine the damped frequency oscillation, ⱳd from (5), the undamped frequency of oscillation, ⱳn from (6), and the value of damping ratio, z using (7). d. Then, find δw using (13) to be inserted into (10).…”

“…Transient stability is a crucial part of a power system operation [6,7]. The stability of a power system is its ability to create re-establishing powers proportionate to the disturbing forces to protect the state of equilibrium.…”

Enhancement of stability margin based on dynamic brake strategy

“…The results of the application of dynamic to single and multi-machine test system are obtained. A comparison between CCT with and without braking as predicted by RACKE method is presented [7][8][9]. The MATLAB/Simulink design considerations of the single and multi-machine presented and discussed along with obtained results.…”