风电功率爬坡事件预测时间窗口的选取

为了完整、高效地预测爬坡事件,提出在一个合适的时间窗口内进行风电功率预测和爬坡事件识别的方法,并重点讨论如何选取合适的预测时间窗。首先通过历史爬坡事件的识别,统计爬坡持续时间的分布规律;利用数据相关性分析研究实例样本数据的可预测性;综合2者的结果确定爬坡预测时间窗口取值的可选范围。其次,基于预测时间窗的目标要求,提出可能的分析指标,在给定取值范围内寻找满足要求的最优时间窗口作为所求预测窗。最后以美国BPA地区的风电功率数据为实例,仿真求出该数据集的预测窗口大小为4.5 h,通过多个评估指标验证了该预测时间窗对实例爬坡预测的有效性。该工作为爬坡事件的预测奠定了重要基础。     

某钨矿斜坡道中高程法标定腰线的全站仪应用

某钨矿斜坡道工程施工中,采用日常方法标定腰线因测量精度较低,满足不了矿山生产需求。试将全站仪用于矿山控制测量、地形测量及工程测量中,结合利用中线点标定腰线和伪倾角标定腰线原理,通过对斜坡道两帮标定点进行测量,然后根据斜坡道平面及剖面进行公式推导,用高程法计算出各标定点与腰线的高差,最后标定腰线点,测高测距结果精确。     

140t／h干熄焦斜道牛腿破损状况及修复方法

简要介绍了梅钢140t／h干熄焦自2008年4月首次烘炉投用后,结合2009年5月及2010年11月2次干熄焦年修中,斜道牛腿耐材的使用状况及修复方法,提出炉衬牛腿结构设计的改进方向,提高于熄焦斜道牛腿耐材的工作寿命。     

Predicting and presenting plausible future scenarios of wind power production from numerical weather prediction systems: a qualitative ex ante evaluation for decision making

This paper is concerned with evaluating techniques to forecast plausible future scenarios in wind power production for up to 48 h ahead, where the term scenario refers to a coherent chronological prediction including the timing, rapidity and size of large changes. Such predictions are of great interest in power systems with high regional wind penetration where a large rapid change in wind power may pose a threat to power system security. Numerous studies have evaluated wind power forecasting methods on ex post statistical measures of forecast accuracy such as root mean square error. Other work has assessed the forecast value by simulating automated decision making for bidding wind generation into particular electricity markets, and in some cases, the ex ante value of a perfect forecast has been assessed. The future, however, will always be uncertain, and decision making always takes place in an ex ante context. This paper discusses how numerical weather prediction (NWP) systems forecasts are produced, with a particular focus on uncertainty and how forecasters might visually present plausible future scenarios for wind power to electricity industry decision makers. It is difficult to quantify the ex ante value of visual wind power forecast information to the complex decision‐making process involved. Consequently, this paper explores qualitative assessments of ex ante value by proposing six desirable attributes for the techniques and the presentation of NWP forecasts to decision makers. It uses these attributes to assess four such methodologies, which include NWP ensemble methods and the recently introduced NWP spatial field approach. Copyright © 2011 John Wiley & Sons, Ltd.     

Model predictive control for wind power gradients

We consider the operation of a wind turbine and a connected local battery or other electrical storage device, taking into account varying wind speed, with the goal of maximizing the total energy generated while respecting limits on the time derivative (gradient) of power delivered to the grid. We use the turbine inertia as an additional energy storage device, by varying its speed over time, and coordinate the flows of energy to achieve the goal. The control variables are turbine pitch, generator torque and charge/discharge rates for the storage device, each of which can be varied over given ranges. The system dynamics are quite non‐linear, and the constraints and objectives are not convex functions of the control inputs, so the resulting optimal control problem is difficult to solve globally. In this paper, we show that by a novel change of variables, which focuses on power flows, we can transform the problem to one with linear dynamics and convex constraints. Thus, the problem can be globally solved, using robust, fast solvers tailored for embedded control applications. We implement the optimal control problem in a receding horizon manner and provide extensive closed‐loop tests with real wind data and modern wind forecasting methods. The simulation results using real wind data demonstrate the ability to reject the disturbances from fast changes in wind speed, ensuring certain power gradients, with an insignificant loss in energy production. Copyright © 2014 John Wiley & Sons, Ltd.     

Design based exploration of medical system adoption: Case of wheelchair ramps

This study focuses on the exploration of wheelchair users' expectations from portable ramps and their adoption factors, then correspondingly offers a smart mass customization design tool. Briefly, portable ramps are generally used by wheelchair users, and provide a temporary solution to increase accessibility in their daily lives. In this research, a rollable ramp was examined as this prototype was developed in a prior funded research and thesis study. Our aim in this study is to explore the critical factors of satisfaction of users' and potential users' of portable ramps. To maximize the usability of portable ramp in various outdoor/indoor spaces and physical structures, an efficient permutation of flexible/adjustable components is offered. The research includes flexibility and customization and many external factors effective for adoption of portable ramp. In this context, three research methods were applied; semi structured-face-to-face interviews, observation, and experimental study. The constructs of the survey were extracted from literature and patent reviews then refined during observation and interviews. Wheelchair users answered a web-based survey with multiple constructs. The survey uncovered that personalization, flexibility, extension capability, and cost is critical. As well, users prefer the chance to try the model before purchasing. The effort needed to carry and learn how to use the ramp seems to be one of the key factors. It is also found that the user's life style and product match has an effect on adoption. At the end of the study, a smart mass customization design tool will be developed, which potential users or sales representatives are able to easily interact with in order to customize the portable ramp.     

山区公路避险车道设置研究

随着国家中东部地区经济的发展,交通运输也得到了前所未有的改善,国家交通建设的重点开始转移到西部地区,西部地区处于我国三级阶梯的高原山区,这就决定了山区交通建设的一个突出特点是长大下坡,这对于重型车辆来说非常不利,极易造成刹车系统的温度失效,酿成惨剧.本文从制动系统的温度效应模型开始研究,通过改变各个影响因素的大小,并进行实验验证,对避险车道的设置位置进行了分析,并对避险车道的长度进行了研究,得到了避险车道的设置位置和设置长度计算公式,为山区公路避险车道的设置提供了参考.     

拉深变压边力机构的设计

针对拉深压边力的理想变化需求,根据凸轮机构运动的特点,设计了一种凸轮斜块组合式变压边力机构。通过凸轮将上滑块的运动转换为斜块的纵向运动,从而调节拉深模中弹簧的压缩量而改变压边力;通过改变凸轮的轮廓曲线、初始位置和转动角度或斜块的倾斜角,可实现预期的压边力变化。     

多点进出型城市地下道路出入口匝道设计研究

交通拥堵成为当今城市发展所面临的普遍问题,受地面资源的约束以及人们对环境品质要求的提高,世界各地越来越重视利用地下道路来解决城市交通和环境问题。在分析了城市地下道路出入口匝道与地上的差异基础上,结合国内外工程案例,研究了城市地下道路的出入口匝道总体布置、出入口设置形式、变速车道、分合流端视距保障等方面的设计技术,并应用于苏州星港街地下道路。研究结果表明,多点进出型城市地下道路出入口设计与地上道路存在差异,需要采用适合地下环境特点的线形指标以及交通安全设施,以提高行车安全,本研究也可为未来城市地下道路的出入口匝道设计和技术标准的制定提供参考。