Measured Based On Synchronized Phasor Dynamic Voltage Stability Prediction And Load Modeling

With developing of electrical industry, the problems of voltage stability become more and more serious. The result of power system bus voltage analysis and prediction rely on the accuracy of the system model and its parameter. The key problem of bus voltage predicted analysis on line is to research the predicted model, which includes simple algorithm, high accuracy degree, long predicted time and good robustness. The appearance and development of synchronized phasor measurement technology based on GPS can supply a new field of power system analysis and control. Bus voltage phasor can be synchronously measured by phasor measurement technology based on GPS, and the data can be used for the research of voltage stability. However PMU can only supply synchronized data, the synchronized measuring data is still the history data in some degree. Above all, the bus voltage control is a local control, and the data transfer and the control process need certain time. Using adaptive AR model to predict bus voltage is different from the traditional method, which depend on the power system model. The AR model is independent of the history data, whose parameters are built and updated by the synchronized data coming from PMU, is used to recursive predict, results in more quick and more accurate outcome.The impact of load characteristics on voltage stability is one of the key problems of power system voltage stability analysis. The load model influenced largely the analytical result of voltage stability in electrical simulation. Firstly, this paper summaries the method of getting the parameters of load model, the static load model and dynamic load model, and analyzes the I/O dynamic load model in simulation. It was difficult to describe different reactive load characteristics by linear discrete models of same order in the past. This paper presents a new reactive load models, which combines static and I/O dynamic load model, and improves the accuracy ofreactive load model simulation. And this paper studies the impact of load characteristics on voltage stability which the key problem of power system voltage stability analysis. The impact of load characteristics on static voltage stability is analyzed in the methods based on V-P and V-Q curves.Secondly, This paper introduces the structure of the GPS system, and particularly summaries the synchronized phasor measurement technology based on GPS, including phasor measured unit-PMU, structure and application of synchronized phasor measured monitor system. Then, the paper introduces the concept and characteristics of time series, and educes the stationary and linear model of time series, the parameter estimate of model, and the recursive algorithm and the prediction formula of model.Adaptive time series approach which combines synchronized phasor measurement technology based on GPS and prediction technology is put forward in this paper. The AR model of time series is applied to predict bus voltage phasor of power system, and the predicted result is analyzed by local voltage stability assessment. All of these are simulated in MATLAB.Finally, adaptive time series approach based on MATLAB is presented in the paper, which is the method using adaptive time series to build models and predict data in MATLAB circumstance. The local voltage stability assessment is introduced in the article. Time series model is built in the synchronized phasor data, which are measured through simulating system model in MATLAB. The AR model of adaptive time series is applied to predict bus voltage phasor of power system, and the predicted result is analyzed by local voltage stability assessment. The research reveals that the AR predicted model of adaptive time sequence predict the voltage phasor under small disturbance, and supply the time for the voltage stability control.