The Research Of Online Voltage Stability Analysis Based On WAMS

In recent years, our country's power system has been developing into a large power grid, high voltage and remote transmission, which is not only extremely important to make use of energy more properly but also enhance the economy. But simultaneously, it also brings huge challenge to the power system's security and stability operation. Among them, voltage stability problem is becoming more and more serious during the development of power system. Based on GPS Technology, Wide Area Measurement System (WAMS) is able to measure the power system's Real-time states and parameters which are distributed in the wide area. Therefore, it establishes a solid basis owing to that they promote the power system's stability control with the local information to the entire grid's harmony control.After reviewing and summarizing the present theory of voltage stability analysis, this article has introduced WAMS into the area of online voltage stability analysis and proposed a method based on WAMS.Firstly, I have introduced the existing static voltage stable index theory, then carried out the simulation and analysis to several voltage stability indices and pointed out their disadvantages.Afterward, based on WAMS'real-time state information, I've proposed a new method to the power system's dynamic equivalence and identify ZIP load model's proportion parameter using Least Square Method, through which we have prepared for the voltage Stability index's inferential reasoning.On the basis of the power system's dynamic equivalence and load parameters identification, the article utilizes the power equation's characteristic(Δ=0) , which takes voltage amplitude as variable, when load power reached the limits of power, to promote the voltage stability state index Lws and the approximate margin index Lwy based on WAMS. Through simulation and analysis of the two indices, I selected Lws to the simulated object. Then Lws and the voltage stability margin index were simulated in a single load, region load and the entire grid growth models. Through the simulation and comparison, showed Lws has the good linearity and the computation rapidity.Finally, the article has analyzed load characteristic, OLTC and generator reactive power limited to the voltage Stability state index's influence, which proved that index had a good description characteristic to the system voltage stability degree.