A direct method to determine the stability of power systems during transients

Author(s):  
Yulin Zhao ◽  
Wei Zhang ◽  
Ruiye Liu
1988 ◽  
Vol 15 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Peter W. Sauer ◽  
Anup K. Behera ◽  
M. A. Pai ◽  
James R. Winkelman ◽  
Joe H. Chow

1987 ◽  
Vol 2 (4) ◽  
pp. 223-230 ◽  
Author(s):  
Jozef Sumec ◽  
Antonino E. Zingali

This paper describes the influence of initial shape imperfections of lattice shells on their general stability. An adequate mathematical model for the analysis of the shell instability by using a direct method (FEM) and a shell analogy method is presented. The reduction coefficient k for calculation of the critical load is derived. An illustrative example is used for comparison of the results calculated by the two numerical methods.


Author(s):  
Andrii Hnatov ◽  
Shchasiana Arhun ◽  
Ruslan Bagach ◽  
Hanna Hnatova ◽  
Valentina Tarasova ◽  
...  

Problem. There are many methods for determining the stability of the energy system. In normal operating condition (normal rated mode), the power system must reliably ensure the consumption of electricity of normalized quality. However, in addition to the normal state, there are emergency and transient states caused by various transients. This is due to the fact that the energy system is constantly changing its parameters. Such changes are determined by variations in the amount of power produced and consumed, as well as the changes in system configuration. Goal. The goal is studying the possibilities of various methods of determining the power systems stability and drawing up the general algorithm of actions for maintenance of their stability. Methodology. When determining the stability of energy systems by the Lyapunov method, two methods can be used: the direct method and the first approximation method. Lyapunov direct method refers to differential methods. To conclude about the stability of the system we do not find a general or particular solution of differential equations, but with their help we find a mathematical function, the complete derivative of which over time allows to obtain a conclusion about the stability of the system. Results. Many methods can be used to determine whether a sustainable energy system is stable or not. The most common are the Lyapunov methods and the Moiseev method. It is determined that the direct Lyapunov method refers to differential methods. The application of the direct Lyapunov method for energy problems is limited. Currently, it can be used only for some individual cases. The method of the first approximation (Lyapunov first method) has received wider application in the solution of power problems. When applying this method, which belongs to the group of methods of full integration, the right-hand sides of the equations are decomposed into power series. Originality. It is determined that one of the perspective directions of increasing the efficiency of the mathematical device work is using the methods of the second order in modeling and optimization of operating modes of electric power systems. This allows you to increase the speed and reliability of the convergence of iterative processes. Practical value. Based on the analysis of various existing methods for solving the problems of stability of energy systems, an algorithm of actions is proposed and developed, which will help to solve the problem of stability in practice.


2007 ◽  
Vol 17 (11) ◽  
pp. 4195-4203 ◽  
Author(s):  
LUÍS F. C. ALBERTO ◽  
HSIAO-DONG CHIANG

A new uniform methodology to study the fast subsystem stability of general two-time scale nonlinear systems is developed. It consists of a direct method that provides estimates of the stability region of the fast subsystem that are uniform with respect to the slow variables, which are treated as uncertainties. The methodology is illustrated on small power systems leading to much improved results in estimating the stability region, critical clearing times as compared to traditional methods. As a by-product, it gives the required theoretical support to justify and to correct the heuristic approaches used in power system stability analysis literature.


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