The Study On Voltage Stability And Controlling Strategy Of Voltage-Reactive Power Based On The Electric Grid

Voltage stability is one of the important issues that the operators pay more attention to in recent years. It becomes progressing prominent with the development of power industry and is becoming the challenge subject confronting with in electric power systems. This paper does study surround the analysis of power systems voltage stability and controlling strategy of voltage-reactive power. Firstly overviews of the overall research work and analysis methods of power system voltage stability are discussed, and the theories and methods of steady-state voltage stability based on transmission characteristic of power systems are stress introduced. The author analyzes actual power network steady-state voltage stability with the nose curve. Secondly, the author summarizes existing state of power load models applying to the study of voltage stability. The main features and defects of present load models used in voltage analysis are discussed. The junction of the first-order mechanical transient model of induction motor to PSASP is realized. With simulating computation, the author studies the effect of variation in parameters and construction of models to the power system transient stability on the WSCC-9 bus system and Hunan Power system using PSASP. The simulating computation shows that the increase of stator leakage reactance makes the system transient stability margin decreased. The transient stability using the third order model is obviously lower than that using the first-order model and constant impedance model. Finally the research work and methods of voltage- reactive power controlling in power systems are summarized systematically. After studying the operation actuality of an actual network, a controlling strategy of voltage-reactive power based on sensitivity method with small signal is advanced. Then an adjustment and controlling schemes aimed to different operation modes are constituted. Simulating computation shows that the results of adjustment of voltage-reactive power are satisfactory.