矿用干式变压器保护设计缺陷的分析及处理

针对KBSGZY---10/630---1.14移动干式变压器保护在设计中的缺陷进行分析研究,并根据现场实际工作经验提出了解决方案,为干式变压器在实际生产中故障排除提供帮助,为干式变压器设计和安全运行提供了保障.     

基于温度场仿真的干式变压器散热设计

随着国家经济的快速发展,变压器的应用已涉及各个领域,干式变压器因其安全、环保、免维护等优点,而被广泛应用。干式变压器的应用环境千差万别,一旦发生故障,将会引起大范围的停电,给工农业生产和人们生活带来诸多不利,因此,对干式变压器的可靠性要求也随之提升。综合分析各类干式变压器的故障原因,有很大一部分故障原因是干式变压器的局部过热而引发的绝缘失效。在故障发生的前后一段时间内,温度场会随着故障的发生而产生不同的变化。为了解温度场的变化,利用有限元分析,建立干式变压器的三维模型,并对模型的电磁场、温度场和流体场进行计算,得到干式变压器的温度场分布。通过干式变压器的温度场分析出干式变压器易存在过热点的位置,对该位置进行故障模拟,获取变压器的温度场分布变化,再根据分布变化对影响干式变压器的散热的出风口位置进行优化模拟。结果表明,模拟结果与试验结果吻合,通风口位置设置会影响产品的散热效果。     

光伏发电用干式变压器关键技术研究

干式变压器作为光伏电站的关键组成部分,具有结构紧凑、易于安装维护、质量体积小、工作效率高、能源损耗少等特点,可以将光伏发电产生的电压提高到电网需要的电压值,对于光伏电站并网系统的电能质量有着至关重要的影响。文章从光伏电站干式变压器使用背景入手,在分析了光伏逆变电路特征的基础上,探讨了干式变压器关键技术研究,从源头上保证光伏电站的运行质量,推动了电力行业健康发展。     

德国将大力发展海上风电

近年来，德国政府提倡大力开发海上风力发电，其目标是到2020年海上风力发电总装机容量达到2万MW，能满足德国15％的用电需求。     

干式变压器的应用

随着#8机炉的建成、投产、安全运行，我厂实现了对干式变压器安全有效、地使用。21世纪的配电变压器将属于性能优越、低噪声、节能、维护工作量小的树脂绝缘干式变压器。因此说，我厂积极推广使用干式变压器是顺应了配电装置的发展方向。     

河北省海上风电发展浅析

海上风能是一种清洁、高效的绿色能源。开发利用海上风能对于减轻环境污染、解决能源危机有着重要意义。文章就河北省海上风能的特点、规划情况进行了分析介绍,并对河北省海上风电开发提出了一些建议与想法,以期为其海上风电的开发建设提供参考。     

基于VBA和SolidWorks的三相三柱式干式变压器铁心标准化的设计

三相三柱式干式变压器在电气化铁道中应用广泛,设计人员在电磁计算单完成后需要对铁心结构进行分析,不同容量的铁心结构大致相同但参数不尽相同,从而导致了设计人员工作的重复性,针对上述问题,运用VBA编程及SolidWorks三维软件的参数化设计理念对干式变压器的铁心结构进行标准化设计,从而提高设计人员的工作效率.     

Pricing offshore wind power

Offshore wind offers a very large clean power resource, but electricity from the first US offshore wind contracts is costlier than current regional wholesale electricity prices. To better understand the factors that drive these costs, we develop a pro-forma cash flow model to calculate two results: the levelized cost of energy, and the breakeven price required for financial viability. We then determine input values based on our analysis of capital markets and of 35 operating and planned projects in Europe, China, and the United States. The model is run for a range of inputs appropriate to US policies, electricity markets, and capital markets to assess how changes in policy incentives, project inputs, and financial structure affect the breakeven price of offshore wind power. The model and documentation are made publicly available.     

基于防护技术的海上风电变流器高可靠性优化结构设计

为了提高海上风电变流器设备或系统的可靠性,对海上风电变流器设备的防护技术进行了详细的分析。针对海上风电变流器自身特点,从密封性、材料、绝缘等方面进行优化设计。     

Understanding public responses to offshore wind power

This paper is about understanding the role and importance of public responses to offshore wind power. It builds on a framework for understanding social acceptance and opposition to onshore turbines, and reviews the emerging research on offshore wind. While less is known about how people will respond to offshore than onshore wind, there is now an emerging body of research. From this literature, several common factors which influence responses have emerged and are discussed here: the (continued) role of visual impact; place attachment to the local area; lack of tangible benefits; relationships with developers and outsiders; and the role of the planning and decision-making systems. The paper argues that, as with onshore developments, the public should be included in decision-making about offshore wind farms, and that they have a key role which should not be underestimated. The paper concludes with some thoughts about the means to involve people and how effected communities might be effectively acknowledged, identified and engaged.     

GHG emissions and energy performance of offshore wind power

This paper presents specific life cycle GHG emissions from wind power generation from six different 5 MW offshore wind turbine conceptual designs. In addition, the energy performance, expressed by the energy indicators Energy Payback Ratio (EPR) Energy Payback Time (EPT), is calculated for each of the concepts.There are currently few LCA studies in existence which analyse offshore wind turbines with rated power as great as 5 MW. The results, therefore, give valuable additional environmental information concerning large offshore wind power. The resulting GHG emissions vary between 18 and 31.4 g CO₂-equivalents per kWh while the energy performance, assessed as EPR and EPT, varies between 7.5 and 12.9, and 1.6 and 2.7 years, respectively. The relatively large ranges in GHG emissions and energy performance are chiefly the result of the differing steel masses required for the analysed platforms. One major conclusion from this study is that specific platform/foundation steel masses are important for the overall GHG emissions relating to offshore wind power. Other parameters of importance when comparing the environmental performance of offshore wind concepts are the lifetime of the turbines, wind conditions, distance to shore, and installation and decommissioning activities.Even though the GHG emissions from wind power vary to a relatively large degree, wind power can fully compete with other low GHG emission electricity technologies, such as nuclear, photovoltaic and hydro power.     

Scenarios for offshore wind power production for Central California Call Areas

In response to the growing interest in offshore wind energy development in California, the U.S. Bureau of Ocean Energy Management delineated three Call Areas for potential leasing. This study provides a comprehensive characterization and comparison of offshore wind power potential within the two Central California Call Areas (Diablo Canyon and Morro Bay) using 12- and 15-MW turbines under different inter-turbine spacing and wind farm size scenarios. Our analysis shows similar daily and seasonal patterns of wind power produced within the Call Areas, which peak in spring and during evening hours. Per-turbine power production is higher in the Morro Bay Call Area due to slightly higher hub-height wind speeds, whereas total power production is higher in the Diablo Canyon Call Area due to its larger size. Turbine type had a negligible impact on average power production per-unit-area because while larger turbines produce more power, they require greater inter-turbine spacing. Combined power production from the two fully built out Call Areas could equal nearly a quarter of California's current annual electrical energy production. A commercial-scale wind farm with a realized power output of 960 MW would require a footprint of at least half of the Morro Bay Call Area or at least a quarter of the Diablo Canyon Call Area. These results provide guidance on offshore wind development over the Central California Coast, and the framework demonstrated here could be applied to other wind data sets in other regions.     

The offshore trend: Structural changes in the wind power sector

In recent years, the wind power sector has begun to move offshore, i.e. to use space and good wind speeds on the open sea for large scale electricity generation. Offshore wind power, however, is not just technologically challenging but also a capital intensive and risky business that requires particular financial and organizational resources not all potential investors might have. We therefore address the question, what impact offshore wind power may have on ownership and organizational structures in the wind power sector. We compare on- and offshore wind park ownership in Denmark, the UK and Germany. The analysis shows that offshore wind power in all three countries is dominated by large firms, many of which are from the electricity sector. In Denmark and the UK, also investors from the gas and oil industry play an important role in the offshore wind business. This development represents a major shift for countries such as Germany and Denmark, in which the wind power sector has grown and matured on the basis of investments by individuals, farmers, cooperatives and independent project developers. The structural changes by which offshore wind power is accompanied have consequences for turbine manufacturers, project developers, investors, associations and policy makers in the field.     

A framework to determine optimal offshore grid structures for wind power integration and power exchange

This paper presents a framework to find optimal offshore grid expansions using a transportation model of the power grid. The method extends the standard mixed‐integer linear programming approach to the solution of the transmission expansion planning problem to account for fluctuations in wind power generation and load; this makes the method especially suited to identify optimal transnational offshore high‐voltage direct current grid structures for the integration of large amounts of offshore wind power. The applicability of the method is demonstrated by a case study of the North Sea region. Copyright © 2011 John Wiley & Sons, Ltd.     

Wind model for low frequency power fluctuations in offshore wind farms

This paper investigates the correlation between the frequency components of the wind speed Power Spectral Density. The results extend an already existing power fluctuation model that can simulate power fluctuations of wind power on areas up to several kilometers and for time scales up to a couple of hours, taking into account the spectral correlation between different wind turbines. The modelling is supported by measurements from two large wind farms, namely Nysted and Horns Rev. Measurements from individual wind turbines and meteorological masts are used. Finally, the models are integrated into an aggregated model which is used for estimating some electrical parameters as power ramps and reserves requirements, showing a quite good agreement between simulations and measurement. The comparison with measurements generally show that the inclusion of the correlation between low frequency components is an improvement, but the effect is relatively small. The effect of including the low frequency components in the model is much more significant. Therefore, that aggregated model is useful in the power system planning and operation, e.g. regarding load following and regulation. Copyright © 2009 John Wiley & Sons, Ltd.     

Review of recent offshore wind power developments in china

Rapid wind power development in China has attracted worldwide attention. The huge market potential and fast development of wind turbine manufacturing capacity are making China a world leader in wind power development. In 2010, with the newly installed wind power capacity and the cumulative installed capacity, China was ranked first in the world. In 2009, China also constructed and commissioned its first large offshore wind farm near Shanghai. Following earlier papers reviewing the state of China's onshore wind industry, this paper presents a broader perspective and up‐to‐date survey of China's offshore wind power development, making comparisons between the developments in the rest of the world and China, to draw out similarities and differences and lessons for the China offshore wind industry. The paper highlights six important aspects for China's offshore wind development: economics, location, Grid connection, technological development, environmental adaptation and national policies. The authors make recommendations for mitigating some outstanding issues in these six aspects for the future development of China's offshore wind resource. Copyright © 2012 John Wiley & Sons, Ltd.