Research Of Voltage Stability Research Articles

Simulation Analysis of Microgrid Voltage Stability with Multi-induction Motor Loads

This paper studies the voltage stability problem in microgrid with multi-induction motor (MIM) loads. Firstly, the dynamic coupling relationship between grid voltage and each motor load slip in microgrid with MIM loads is deduced based on the power balance theory of power system. Then, a multi-source and master slave control based microgrid model is built, where Matlab/Simulink software is used to analyze microgrid voltage stability under circumstances of MIMs superimposed starting and microgrid fault. Through simulation calculation and analysis, the measures to improve the voltage stability of microgrid with MIM loads are proposed. According to the simulation results, the interaction between MIM loads has great influence on microgrid voltage stability. In addition, the critical cleaning time (CCT) of series connected master slave control based microgrid is affected by the distance between three phase short circuit fault location and the induction motor load location, as well as the distance between fault location and main control unit. The microgrid voltage stability can be effectively improved by applying methods of superimposed starting strategy and fast motor cutting strategy. The conclusion provides a reference for voltage stability research and control of the microgrid with MIM loads.

The Dynamic Analysis Approach Research of Voltage Stability

Because we did not consider the dynamic characteristics of system components in static voltage stability analysis, the reliability of the static analysis of the results is reduced. So if we want to explain the mechanism of the voltage instability fundamentally, we must adopt the method of the dynamic analysis. This paper discuss the small disturbance analysis method and the continuation algorithm analysis method of the dynamic analysis method, then research the mechanism of voltage collapse and the results of the dynamic analysis. A load model and the dynamic system for the voltage stability studies is the key of the voltage stability to the maturity.

The Analysis of Voltage Stability in Power System

In the static voltage stability analysis, we usually use the vertex of the P-U curve as the critical point of the voltage stability. This method can not reveal the problem of the physical essence of the voltage stability and the instability mechanism. We must adopt the dynamic analysis method to analyze the voltage stability from the dynamic factors. This paper discuss the small disturbance analysis method and the continuation algorithm analysis method of the dynamic analysis method, then research the mechanism of voltage collapse and the results of the dynamic analysis. At the same time, a load model and elements of the system dynamic model suitable for the voltage stability analysis is the key and difficult point of the voltage stability research.

The Research of Voltage Stability in Wind Power System

Wind power is a kind of special electric power, because of the volatility of the wind, making voltage stability has become an important research problem wind power system must facing with. Therefore, according to the relevant current research status and the main existent problems of wind power system, expounding the difference of voltage stability between the conventional energy sources and the wind power, and the influence of voltage stability to the power system which caused by wind power system. This paper mainly from the definition and the classification to introduce the voltage stability; from the research contents and methods of static and dynamic voltage stability to analyze power systems which contains wind farms, especially emphasizing the necessity of the bifurcation theory used in power system contains wind power. Finally points out that the research trend of analysis and improvement in this area.

A Full Dynamic Voltage Stability Research Based on Time-domain Simulation

The voltage stability is substantially a dynamic stability, but the primary method which is more mature and engineering practical to analyze the stability of voltage is still static analysis. The time-domain simulation is an important measure in research of complex power grid. With the development of full dynamic simulation technology, the research of dynamic voltage stability by using full dynamic simulation program which is based on time-domain simulation can be carried out. This paper uses full dynamic simulation program in dynamic voltage stability research, lays special stress on research in how generator over-excitation limiter functioned and influence in dynamic voltage stability research, and raise 2 methods and steps to figure out dynamic stable voltage in both over-excitation counted and not counted. The simulation results of examples indicate the correctness and effectiveness of these methods, and also fully verify the function and influence of generator over-excitation limiter in full dynamic voltage stability research.

Research of Photovoltaic Grid System Voltage Stability Based on the Bifurcation Theory

In grid-connected photovoltaic system, the inverter, grid device, power electronic devices etc. They consume a large quantity of reactive power; mostly in distribution system, a perceptual load must also consume reactive power, these makes big interference interconnection of photovoltaic system after serious test the voltage stability. Therefore, carry on research of voltage stability in grid-connected photovoltaic system has important significance. With the voltage stability, voltage quality, analysis the possible influence of photovoltaic grid power system on power grid in safe and stable operation. Discuss probable bifurcation behavior in photovoltaic grid system. Introduce the basic concept of bifurcation, and then review the application of bifurcation theory in research of voltage stability from two aspects: static bifurcation and dynamic bifurcation. Finally take a look at bifurcation theory research of photovoltaic grid system voltage stability.