Advanced Materials Research Vols. 860-863

Abstract: With the continuous development of wind energy resources, wind power technology has been integrated into the modern power system. In this paper, according to the Power System Incorporating Wind Farm, selecting typical data distributed Power flow calculation of Built power network. According to data from the results show that grid-connected wind power system, Due to the directly affected by the influence of the wind speed size into the injection power, cause the whole trend distribution network is presented in a state of random changes, thereby affecting the network power loss of change. In order to improve the network voltage change, this paper puts forward some feasible measures to improve the network voltage method.

Abstract: Wind is one of the most promising sources of alternative energy. The construction of wind farms grows quickly in China. It is necessary for stakeholders to estimate investment costs and make good decisions on a wind power project by making a budget for the investment. However, the identification of rational investment practices is technically challenging because of the lack of scientific tools to evaluate optimal decisions. A multi-criteria evaluation method was proposed to select rational investment strategy for wind farm construction. The method is based on the analytic hierarchy process (AHP) together with a technique for order preference by similarity to ideal solution (TOPSIS). A decision problem hierarchy with three layers were investigated. The top layer is an objective layer for evaluating the investment rationality. The intermediate layer includes three evaluation criteria, that is, configuration of wind turbine generator systems, physical environment and social environment. Some relative and important indicators for each criterion are in the low layer. The evaluation results illustrate that the proposed method is practical and helpful to indentify the investment rationality for wind farms.

Abstract: The energy storage technique is one of the most effective means for the real-time wind power regulation. Firstly, this paper discussed the operation mode of energy storage system for real-time wind power regulation. At the same time, we proposed that the energy storage system applied into the real-time wind power regulation should be of the properties of high power density, high energy density and long cycle life. By analyzing the properties of battery and supercapacitor, we arrive at the conclusion that the battery-supercapacitor hybrid system obtains the enhanced characteristics to meet the performance requirement for energy storage system. In order to achieve the real-time wind power suppression, we carried out a comparative research on the topology of battery-supercapacitor hybrid system. The operation mode of each topology was discussed. From the standpoint of practical engineering, the merits and deficiencies of each topology were explored.

Abstract: To model the fluctuation characteristics of wind power is the basis for solving wind power integration problems. This paper studies the cluster effects of large-scale wind power, proposed a series of new cluster effect evaluation indexes, which have clear physical meanings and is conducive to the actual needs of the power system; based on Gaussian Mixture distribution, the probability distribution model of the cluster effect is established, which was verified with the actual operation data; The paper then proposed confidence interval model of cluster effect evaluation indexes, studied the variation of the cluster effect, shown the power function relationship between cluster effect evaluation indexes with scale of wind power.

Abstract: With the capacity of wind power into power system increasing year by year, the impact of wind power characteristics (random and intermittent) on the system stable equilibrium is outstanding. To configure spinning reserve properly, this paper establishes a relatively complete optimization model of spinning reserve for power system with wind integrated. Using the similar samples to train prediction model, the precision of prediction is improved. The equivalent load duration curve (ELDC) considering load fluctuations and unit outage, is revised by analyzing the probability density of wind power prediction deviation. And the last, this paper gives an example to verify the theory.

Abstract: This article is to present the study results of small multi blade wind turbine for use in low wind speed area. In this experiment, the wind turbine has a diameter is 1 m, 30 blades. Each blade has the chord length of 6.5 cm, the length of 0.25 m, which has a curvature plate ratio of 0.15, and blade setting angle of 30 degree. Wind turbine was tested by wind tunnel at wind velocity of 3, 4 and 5 m/s. The results from the test run of, this the wind turbine give maximum mechanical power in each wind velocity of 3.66, 9.91 and 21.76 watts, respectively. From the dimensional analysis of wind rotor turbine by using Buckingham Pi theorem, the wind turbine is up to two times as large that is 2 m diameter; give maximum mechanical power increased to 14.64, 39.24 and 87.04 watts, this power can be generate electric power or use for water pumping for a household.

Abstract: Large scale wind farm output variation always deteriorates the system stability. To study this problem, this paper builds the model of power system with the integration of large-scale wind farm based on BPA. The simulation results show that large oscillations of voltage and rotor angle of system will happen, when three-phase short circuit fault occurs on the main line for transmitting wind power. With wind farm output decreasing, the transient stability and small-signal stability of power system will be improved.

Abstract: Traditional wind turbines are difficulty to work well in built-up areas due to wind conditions of low speed, turbulence and frequent changing direction. A long-term wind observation work has been done to understand the characteristics of urban wind by installing a small weather station on the balcony at top floor of a residential building. Based on the observation results, a new structure for low speed wind turbine in built-up areas was designed. This structure can be used for either horizontal axis wind turbine or vertical axis wind turbine. Some mesh models were established to simulate the effect through CFD software. In this structure, growth rate of wind velocity is about 1.25 times; wind turbulence converts to laminar; and yawing angel of turbine motor shafts neednt change any more. Prototype testing draws better conclusions: growth rate of wind velocity is more than 1.4 times. Therefore, traditional wind turbines can work well in built-up areas through this new structure.

Abstract: This paper investigates the subsynchronous interactions (SSI) in DFIG-based wind farm and turbine-generator (T-G) bundled system which is integrated through series compensated transmission line, the results reveal that the integration of DFIG-based wind farm could improve the subsynchronous resonance (SSR) damping of the nearby turbine-generators. Then supplemental controls of DFIG-based wind farm are used to mitigate subsynchronous control interaction (SSCI) of the DFIG and multi-mode SSR of the nearby turbine-generators. The supplemental controls are added to the reactive power control loop of GSC (grid side converter) for DFIG. Given that no additional device is needed, this supplemental control could be the most promising measure for SSR and SSCI mitigating.

Abstract: This paper simulates the wave condition of Shandong Peninsula and Yellow River estuary with SWAN (Simulating Wave Nearshore) model, which is driven by wind fields from 1996 to 2007. And then hindcasted wave data and the buoy data compared, which shows that hindcasted wave data are validated with buoy data. Finally, wave and wind energy of Yellow River delta are assessed by 12 years hindcasted wave data and the wind data, which is 10m height above the ground level. The result of assessment shows that Yellow River delta has large wave and wind energy potentialities. If the wave energy and wind energy can be used effectively, the pressure of power supply of Dongying will be relieved.