Design And Implentation Of Automatic Voltage Control System Of Wind Farm

In recent years, with the rapid development of wind power generation technology and national policy support for renewable energy, our country s wind power industry has made rapid progress. But at present, due to the development trend of our country s power grid and distribution characteristics of wind resources, our country s wind power development is showing a large-scale centralized development characteristics, and large wind farms located in the more remote areas are away from load centers, the areas are in the end of power grid and power grid structure is weak. Therefore, large-scale wind power needs to be transmissed to the load center by ultra high pressure, long distance transmission lines. Because of the ultra high voltage transmission channel has larger charging power and wind power itself exists the volatility and uncertainty, which making large-scale wind power centralized access point and transmission channel trend produce strong volatility, leading to the node voltage of regional power network centralized by large-scale wind power ups and downs as the change of wind power output, affect seriously the voltage quality and stability of the power grid operation. Therefore, it has important practical significance to study the reactive power voltage characteristic and control strategy of large scale wind power centralized access power network.In the first, this paper introduces the research status of the wind farm reactive power voltage control technology, the basic principle and characteristics of the reactive power voltage control measures are studied and analyzed. Secondly, according to the requirement of practical engineering, we propose the overall control strategy of reactive power and voltage of wind farm. The strategy is the control of the bus voltage and the terminal voltage of the wind turbine is realized through the control of the reactive power of the wind farm. On the one hand, in view of the wind farm reactive voltage stability control problem, the specific ideas is through the modeling of the wind farm, then considering comprehensively the reactive power demand of the step-up transformers, the box transformers, the set wire lines, the wind turbines and other equipment in the calculation, and real-time calculating wind farm reactive power margin overall, coordinately using reactive power regulation capability of SVC, wind turbine, taps and capacitor banks and maintaining the wind farm reactive power balance and voltage stability, and keeping enough margin to deal with unusual circumstances to achieve risk control. On the other hand, for the wind turbine control terminal voltage stability problems, specifically the idea that the state is estimated by the wind farm, realizing comprehensive monitoring of wind farm, while avoiding the impact on the calculation due to the ineffective sample data to ensure overall system reliability. By analyzing wind farm voltage current and balancing the voltage between each set wire lines, we try to control wind turbine in phase running, and avoid the occurrence of the wind turbine off the network caused by voltage fluctuations. Then, an intelligent reactive power voltage automatic control system of wind farm is designed and developed on the basis of the proposed control strategy. At the same time, we describe the overall framework of the system and introduce of the system of each sub module with the work principle, function and configuration detaily. Finally, the designed system is applied to the practical engineering; we consider the test case of Gansu Bay Bridge and east of bridge of Jiuquan wind farm AVC system inside the loop running as an example and evaluate the performance of the designed control system. It is proved that the validity of the designed wind farm reactive voltage automatic control system and the rationality of the control strategy.