A Study On Hopf Bifurcation And Voltage Instability For The Single-machine Inifnite-bus Power System Model

In order to more rational use of energy, and improve the economic effects, environmentalprotection, power system at home and abroad increasingly large unit, large power grids,ultra-high voltage and long-distance transmission direction. Meanwhile, many incidents ofvoltage collapse events happened in a number of large power grids in the world, causinghuge economic losses. The different levels of voltage stability accident happened in ourZhangjiakou, Xuzhou grid too.Current academic research on power system voltage instability has not yet formed acomplete theoretical system. Power system voltage stability analysis revealing the voltageinstability principle has great significance. In this paper, bifurcation theory is used to analyzepower system voltage stability with the software AUTO07. Then we will discuss theinfluence of load, OLTC to power voltage and concrete measures to enhance the powersystem voltage stability. The main contents are summarized as follows:1) The power system is a highly nonlinear system of power system voltage stability, wemust first understand the definition of voltage stability, classification, and the meaning ofvoltage stability study. On this basis, several existing methods are mentioned for voltagestability studies. There are many factors affect the power system voltage stability analysis, sowe must establish a reasonable mathematical model of the power system. As we know. thepower system is composed of a variety of static and dynamic components, such as generatorsequation, load equation and the network model, so is very important to choose a reasonableelement model of voltage stability analysis;2) AUTO07basing on UNIX system can accurately track the balance point of the system,calculate, judge the bifurcation point and track the branching direction. With the bifurcationtheory more and more used in different areas, the AUTO07software become a powerful toolfor the majority of scientists to analyze the bifurcation problem. This article describes theinstallation, use, and some of the limitations. After that AUTO07software transplanting tothe WINDOWS and LINUX will be mentioned.3) Bifurcation theory is a powerful tool for the analysis of structural stability of nonlineardynamic systems and power system is essentially a dynamic nonlinear systems. Usingbifurcation theory analysis of power systems not only reveals the mechanism of powersystem voltage instability but also has important theoretical value and actual value to powersystem analysis. This article will introduce the bifurcation theory and its application in theanalysis of power system voltage stability. And we will introduce the power system model. 3) Bifurcation point of the strike is a complex process. After we have built a reasonablepower system model, then we will introduce a matrix splitting technique to achieve theJacobi matrix’s model order reduction. Then hopf bifurcation point will be calculated andsystem’s balance point curve will be tracked according to the definition of the Hopfbifurcation point at the same time. At last, we will introduce the voltage stability with tool ofAUTO07.