Research On The Operation And Control Method Of Wind Power Generation System

Wind energy is a kind of clean, practical, economic and environmentally friendly alternative energy. Together with other forms of renewable energy, wind energy can contribute to a sustainable energy foundation for the human developing. In the future energy system, wind power is of strategic importance.Wind energy has been utilized for many thousand years. The history of modern wind power research and development is also more than 30 years. Many governments invested a lot of money for long-term wind power research activities. In recent years, the wind power installed capacity has gained dramatically high growing rates in China, almost doubled her total installed capacity every year.Wind energy is characterized by its low energy density, variability, intermittence and can not be directly stored. These characteristics lead to lots and lots of problems remained unsolved in the domain of wind power research. The variation and intermission of wind has notable impact on the wind turbine operation, control and wind power integration into power grid. Obviously, the variability and intermittence of wind are the primary reasons of problems involved in wind power operation and control. Based on the above mentioned analysis, this dissertation researched on several problems related to wind power operation and control, including wind characteristics, short-term wind speed simulation, hourly wind speed forecasting, short-term power system load forecasting, combined operation of hydro power generation and wind power generation, as well as synthesized power and frequency control of wind power generation system assisted through flywheels. The main contributions of this dissertation were summarized as follows.(1) A large amount of literate related to wind energy utilization has been studied. The domain of wind energy research has been cataloged into 5 main subdomains:①wind power meteorology, wind energy resource assessment, and wind power project construction;②wind power equipment and power grid integration;③wind power system operation and control;④wind farm management and wind power security issues;⑤new concept of wind power generation, experimental research and field measurement. Reviewing remarks have been made on every subdomain. The purpose of this literate reviewing is directed to provide a valuable clue for deep research on wind energy development. (2) A short-term wind speed simulation method has been proposed. The basic idea of this method is as follows. Firstly, a primary wind speed series was obtained through a model based on Kaimal wind speed power spectral density. Then, a method called spectrum mimicry was applied to the primary simulated wind speed series to correct it. After correcting, the final resulting simulated wind speed series could be able to reflect the special site characteristic wind speed fluctuations. This simulation method should be useful in a wide area of studies, such as other wind engineering and signal analysis.(3) A vector autogression model has been proposed for the hourly wind speed forecasting and short-term power system load forecasting. The main ideas of the proposed modelling and forecasting method are as follows. Firstly, the periodic hourly wind speed time series or short-term power system load time series was vectorized according to the different time of a day. This processing transferred a univariate time series to a vector time series. Secondly, a vector autogression (VAR) model was set up with vectorized time series. Finally, the resulting VAR model was applied to the forecasting of hourly wind speeds or short-term power system loads. The periodic variation information was preserved in the transformation of a univariate time series to a vector time series, so the resulting VAR model could reveal more foundational characteristics hided in the time series. The proposed vectorization of a univarate time series is a generalized method, and could be suitable for modeling and forecasting of other periodic time series.(4) A linear programming model was proposed for combined operation of a hydro power station and a wind farm. The real value of the model is embedded in its objective function and constrains considered in the model. The solution obtained from the proposed revealed quatificationally the complement between hydro power and wind power. The complement advantages come from the fact that the hydro power station can provide capacity supporting to the wind farm and simultaneously the wind farm can provide energy supporting to the hydro power station.(5) A synthesized power and frequency control method of wind power generation system assisted through flywheels has been proposed. A scheme of wind power generation system assisted through flywheels has been studied, in order to ensure that the flywheel-wind power generation system has justice power and frequency control capability as a traditional generation unit.At the end of the dissertation, five main innovative results were summarized, the application of these results and a perspective on the further research opportunity were presented.