Wind Power Prediction Approach And System

The intermittent and volatility of wind energy brings rigorous challenges for the safety and stability of electric power system, when large scale wind access system. An effective technique to solve this proble is to predict wind power. Also, the wind power prediction can provide supprots for the complementary opperation of wind power, photovoltaic power, storage energy, hydropower and the diapatching control of power system. The prediction approaches of wind power, however, are not be researched in depth enough in China. Moreover, the corresponding prediction system is less. So it is significant theoretically and practically to research the prediction approach of the wind power.To explore the prediction approach of wind power with higher accuracy, the wind speed prediction, the power curve model and the power prediction have been systematically studied in this paper based on two typical wind farms. The research achievements were expected to offer guidance for determining the prediction technique route and developing the prediction system.The main achievements are as follows:The wind speed prediction approach was deeply studied firstly, due to that it can provide support for the wind power prediction. 1) A new prediction approach for wind speed based on EMD was proposed. The wind speed prediction results were compared with those gotten through the other conventional methods. The results show that when applying the introduced approach, both the wind speed single-step prediction accuracy and the multi-step one get improved. The reason lies in that the original wind speed series are self-adaptively decomposed into some normal components after the preprocessing of EMD. As a result, the coupling and interferences among the components are weakened. So the prediction models are easier to build, furthermore, the prediction accuracy is enhanced. When the multi-step prediction for wind speed was performed based EMD, the prediction results of the reconstitution components were overlapped adaptively. In doing this, the influences of the component with the more drifts on the whole prediction effects are weakened, so the prediction precision can be further improved. 2) A novel direct multi-step prediction approach for wind speed based on chaos analysis was presented. According to the phase space reconstruction theory, the phase space of original wind speed is reconstructed, which could reflect the inner rules embedded in wind speed and is helpful for the determination of RBF network. As a result, the prediction accuracy gets increased compared to the RBF method.The power curve plays an important role in the power prediction. So the modeling of power curve was studied. A power curve modeling approach was introduced, which was nominated as"exponentially forgetting modeling". The simulation results show that its precision is satisfied, no matter the input is real wind speed and predicted wind speed. Compared to RBF, the introduced model is more suitable to be applied in power prediction due to it is easy to employ and possesses explicit physical meaning.Based on the above investigations, the power prediction approach was systematically researched, which mainly focused on the two prediction ways and some algorithms. The application example shows when the ultra-short power is predicted, the different prediction scheme should be chose according to the predicted objects. But no matter which scheme is confirmed, the algorithm based on EMD has highest accuracy. On the basis of these, the technology options of power prediction suited for China is proposed. While the short power is predicted, the power curve approach has better effects comparing with RBF, on the premise of the NWP is not matured.The power prediction system was developed in this paper, which had been installed in some wind farms and the electric dispatching centers. The practices indicate that the ultra-short and short power prediction with higher accuracy can be real-timely implemented by means of the system. At the same time, the system is safe, user-friendly and easy to operate.