Study Of Improvement Measures For Small Signal Stability On A Provincial Power Grid

With the rapid development of our country’s power industry, it becomes more and more important to keep power system operate stably. Faced with all kinds of small interfering at any time, it’s particularly necessary to improve the small signal stability of power system.When faced with small disturbances, power system has the ability to restore the original operating state automatically, and at the same time it’s not aperiodic out-of-sync. This is called power system small signal stability. At present, a lot of methods have been used for small signal stability analysis, while eigenvalue analysis is one of the most widely used methods. However, with the constant expansion of the power system, there are more and more types of system components. In this case, plug-modeling technology is introduced to make it flexible to insert any new element and then create a system model. Based on the state matrix of the system, we can take full advantage of the eigenvalue analysis to analyze the small signal stability of power system.When we analyze the small signal stability of power system, usually we can get a few factors that reflect the small signal stability, which will provide a theoretical basis for improving the small signal stability. Currently, many methods have been used to improve the small signal stability of power system. As a kind of controller, power system stabilizer is able to improve small signal stability by increasing the damping, which is installed in the generators mainly involved in the electromechanical oscillation modes. In addition, with some reasonable change, both operating parameters and network parameters in the power system can contribute a lot to improve the small signal stability of power system.Considering the system scale of provincial power grid, this paper mainly talks about how to improve the small signal stability of power system. Firstly, according to the specific data of provincial grid, small signal stability analysis is carried out. Secondly, we need to identify the electromechanical mode whose small signal stability is relatively weak, and its main generators. Finally, through some adjustments of control parameters (PSS gain factor), operating parameters (PV voltage and generator power) as well as network parameters (transformer reactance and line reactance), we should try to know what impact they will have on the power system. In a word, all improvement measures that have been carried out are just used to provide some advice to improve the small signal stability of provincial power grid.