风力发电机组的台风适应性设计方法研究

设计工况决定了风电机组的外部载荷和运行环境。由于目前的风电设计标准没有考虑台风环境的影响,运行于台风地区的风电机组遭到破坏的风险增大,制造和运营成本增加。利用观测到的热带气旋数据分析了台风过程中的湍流强度、阵风特性和风向变化特性,提出了包括台风特性、台风工况、结构失效分析设计、台风控制策略和运维策略的系统性的风电机组台风适应性设计方法。文章基于上述方法,计算分析了风电机组在不同工况条件下的载荷;结果表明,采用本文方法设计的风电机组,应用于台风多发地区,具有更好的经济性和安全性。     

虚拟式风电机组功率特性测试仪的研发

为了实现对风电机组功率特性的测试,依据IEC标准对风电机组的功率特性测试的方法、原理进行了研究,提出了风电机组功率特性的现场测试方法,并且结合现代虚拟仪器技术设计并开发出实用的风电机组功率特性测试分析仪,该仪器是在VMIDS系统基础上成功研制出来的,在成功完成对风电机组各参数提取的同时,能分析出风电机组的各项特性.     

风力发电机组防雷设计

由于雷电现象具有非常大的随机性,因此不可能完全避免风电机组遭受雷击,只能在风电机组的设计、制造和安装过程中,采取防雷措施,使雷击造成的损失减到最小。从雷电发生的机理和雷击过程入手,对风电机组的防雷技术进行阐述分析。     

用软件对风资源进行准确评估——5％的评估误差就可能导致项目从赢利变为亏损

作为风电项目前期工作的重要一环,风电场规划区域的风能资源评估是项目是否可行最重要的判决依据之一。科学准确的风能资源评估,可以有效规避投资风险,显著提高规划风电场的年发电量,延长风电机组运行年限,降低风电场建设和维护成本。     

风电并网价值分析

风电的接入因能替代常规机组发电而具有正向价值,同时也因会改变系统中不同类型机组的运行方式而带来负向价值。为衡量风电并网价值,建立了含风电机组日前优化调度模型,模型中考虑了不同机组的特性及负荷与风电的随机性和误差,从风电渗透率、负荷与风电预测误差和负荷与风电相关性3方面分析了它们对风电价值的影响。结果表明：风电并网容量较小时,风电具备减小系统运行成本的价值;风电并网容量较大时,机组启停费用增加,致使风电不具备并网的价值。     

基于TMD的风力发电机组降载设计方法

针对山西某风电场44#风电机组在水平垂直于传动链方向的突发性、间歇性振动而导致风电机组振动超限停机。设计了质量阻尼调谐装置(TMD)对风电机组进行减振,并对TMD减振装置的原理和设计流程进行了详细的介绍。同时,设计开发了TMD减振装置,成功应用于风电现场。应用结果表明:设计的质量阻尼调谐装置在机组满发工况下减振效果能达到40%以上,能够减轻风电机组机舱振动幅度,消除风电机组机舱振动故障,减少风电机组的故障停机时间。     

兆瓦级风电机组的载荷计算与性能研究

作为一种取之不尽、用之不竭的清洁能源,风能逐渐成为近年来最受人们青睐的重要资源,由此也推进了风电产业的快速发展。风电发电的核心部分是兆瓦级风电机组,本文介绍了兆瓦级风电机组的性能研究现状,以及目前相关技术中存在的问题,并就其载荷计算给出了公式。     

海洋风电支撑结构的随机性动力优化设计

研究了海上风电三脚架支撑结构的随机性优化分析。与陆上风电相比,海上风电支撑结构成本较大,而支撑结构受到复杂载荷作用,且其海上维修、安装费用较大,在设计中必须要考虑支撑结构在海洋环境下的安全可靠性。因此采用了随机性动力优化设计的方法一方面降低了成本,另一方面充分考虑了海上风电工作过程中由于随机性因素引起的安全性问题。首先考虑了风、浪、流及地震载荷作用,对海上风电支撑结构进行了整体动力分析,确定结构随机性优化的响应约束条件。然后通过实验设计的方法简化设计变量,通过代理模型的方法构造变量与响应之间的数学模型。最后在代理模型基础上采用全局优化算法对海上风电支撑结构进行随机性优化。优化后的三脚架支撑结构在满足强度与刚度设计要求下即节省了一定的成本又提高了结构的可靠性。研究算例表明,所提出的海上风电支撑结构的随机性动力优化分析研究具有可行性。     

风电齿轮箱的设计与工艺探讨

随着我国风电产业的迅速发展,风电装备制造业也呈现出了蓬勃的发展前景,风力机组中最重要的部件风电齿轮箱也引起了人们越来越多的关注。本文主要从齿轮箱的轴承、设计、状态监测、润滑系统以及制造工艺等方面研究了风电齿轮箱存在的问题,同时给出了相应的建议。     

基于二次参数化技术的风电机组序列化建模

针对常规建模方法在庞大复杂风电机组应用上的不足,在建立单台风电机组全参数化模型的基础上,以风电机组序列整体为研究对象,根据同序列不同功率机组之间各零部件设计参数变化规律,研究应用二次参数化技术和参数序列化方法实现了高效的风电机组模型建立与管理;并结合三维模型参数驱动技术,研发了风电机组序列建模系统,可有效减少建模和造型工作量、降低设计失误率、提高设计效率,验证了该建模方法的正确性与合理性。     

低温型风力发电机组的机舱空调系统

介绍了陆上地区使用的低温型风力发电机组机舱空调系统的原理和组成;指出了设计中要注意的要点和机舱空调系统的主要结构;装设有空调系统的风力发电机组,可使机舱内的环境满足各部件的使用要求。通过对保温结构、加热、密封及通排风等的通盘考虑和全新设计,达到降低机组的制造成本,并提高机组的性能,实现风力发电机组在极低温度环境下的使用要求。     

夹层结构纸板压缩剪切夹具的改进及其验证

针对国家标准压缩剪切夹具测试夹多种层结构材料的剪切性能时,需要多个夹具,且夹具制作成本高的不足,对其进行了改进:将与试样粘合的加载板改为组合式结构,这样可以制作多组样品粘合板,测试时只需要组装即可,大大降低了夹具制作成本,提高了试验效率,而且样品准备制作更加方便。 通过试验对改进的组合压缩剪切夹具与标准夹具进行了对比验证,结果表明组合夹具与标准夹具相比所得数据稍有差别,但压缩剪切载荷最大值差别在依10% 以内,提高了夹具的制作精度后,组合夹具完全可以代替标准夹具。     

负荷传感器试验的准静态加荷方法研究

通过对叠置加荷方式工作过程的分析，讨论了非静态加荷问题。由于传感器和仪表的静态性能与动态性能的差异、动态性能的离散性，以及测量过程中采样频率、采样间隔和数据处理等因素均会对试验的力值计量精度产生影响，因此采用非静态加荷方式进行负荷传感器负荷特性试验会产生测量误差。理论分析证明，采用非静态加荷方法提高试验工作效率、保证测量精度的关键在于加荷速度的控制和正确的采样与数据处理方法。本文提出了准静态加荷这一概念，并对准静态加荷方法的实现及其在负荷传感器试验中实施的可行性进行了理论和试验研究。结果表明，受技术条件的限制，动态加荷是不现实的，而准静态加荷确是可行的非静态加荷方法。它满足负荷传感器负荷特性试验中试验工作效率高、保证测量精度、容易实施和生产成本低的要求。     

Observation of the fracture path development in mortar beam specimens

The development of the fracture zone in beam specimens subjected to three-point and four-point bending has been observed and was related to the overall load-deflection relationship. A video technique together with the computer scanning facility were used to detect the initial macrocracks appearing before the attainment of the maximum load and also to record the fracture path formation in the postpeak portion of the load deflection curve. A comparison is made between unnotched and notched beams that are prepared for fracture testing from the standard size concrete beams. Due to its simplicity and cost effectiveness, this technique could be applied in many practical situations to detect the initial critical cracks and to reexamine the test results on the repetitive basis.     

Design of an integrated quality assurance strategy in production systems

High-quality of products is a critical issue for manufacturers to maintain their competitiveness in global markets. For this reason, more attention has been paid by operations managers and academics to the design of quality assurance strategies, acceptance sampling plans and inspection allocation problems. In the last decades, international research has studied and introduced several models and approaches to investigate these issues. The purpose of this paper is to provide a new methodology for designing and selecting correct integrated quality assurance strategies, defining cost models for acceptance policies and inspection station configurations. Generally, high-quality of items is guaranteed by avoiding defects, mainly caused by non-conforming components, resulting from instantaneous and standard infant mortality. Thus, an optimal acceptance policy is defined in order to reduce the instantaneous infant mortality defects. A closed-form equation has been introduced to determine easily and quickly the optimal percentage of checked items. Furthermore, a more convenient inspection station configuration is determined in order to minimise the expected total cost, composed of testing, inspection and penalty cost elements. The innovative concept of defect rate as an inspection time variable dependent has been introduced. The impact of different economic and survival parameters on designing inspection policies is also investigated. Finally, a real-life case study demonstrates the applicability of this methodology in real production systems and several considerations are reported about the future research, that the authors will carry out.     

商厦空调冷水机组供电负荷计算的探讨

本文通过对某型号空调冷水机组用电负荷计算分析，探讨在供电负荷设计时，如何力求做到计算负荷与实际负荷相符，避免造成不必要的浪费。     

Robust concurrent topology optimization of multiscale structure under single or multiple uncertain load cases

Concurrent topology optimization of macrostructure and material microstructure has attracted significant interest in recent years. However, most of the existing works assumed deterministic load conditions, thus the obtained design might have poor performance in practice when uncertainties exist. Therefore, it is necessary to take uncertainty into account in structural design. This article proposes an efficient method for robust concurrent topology optimization of multiscale structure under single or multiple load cases. The weighted sum of the mean and standard deviation of the structural compliance is minimized and constraints are imposed to both the volume fractions of macrostructure and microstructure. The effective properties of the microstructure are calculated via the homogenization method. An efficient sensitivity analysis method is proposed based on the superposition principle and orthogonal similarity transformation of real symmetric matrices. To further reduce the computational cost, an efficient decoupled sensitivity analysis method for microscale design variables is proposed. The bidirectional evolutionary structural optimization method is employed to obtain black and white designs for both macrostructure and microstructure. Several two-dimensional and three-dimensional numerical examples are presented to demonstrate the effectiveness of the proposed approach and the effects of load uncertainty on the optimal design of both macrostructure and microstructure.     

Nodal probabilistic production cost simulation considering transmission system unavailabilty

A nodal probabilistic production cost simulation method is described for power system long-term expansion planning considering unavailability and delivery limitation constraints of the transmission system. This new nodal production cost simulation model includes capacity constraints and unavailabilities of generators as well as transmission lines. This simulation methodology comes from the nodal composite power system equivalent load duration curve (CMELDC), based on a new effective load model at load points developed by the authors. The nodal CMELDC can be obtained from convolution integral processing of the outage capacity probability distribution function of the fictitious generator and the original LDC. It is expected that the new simulation model based on the nodal CMELDC proposed here will provide solutions to many problems based on nodal and decentralised operation and control of electric power systems under a competition environment. The nodal CMELDC based on the new model at load points can extend application areas of nodal probabilistic production cost simulation, probabilistic congestion cost assessment, analytical outage cost assessment and nodal reliability evaluation and so on at load points. The characteristics and effectiveness of this new proposed methodology are illustrated by a small system case study using a network flow and enumeration method.     

住宅建筑集中空调系统收费标准的制定与探讨(下)--用户侧收费模式浅析及能耗费用计算

对住宅建筑集中空调系统的供冷(热)收费标准及收费模式进行探讨,指出制定收费标准时应遵循的原则,简要介绍四种收费模式,对某小区用能价格变化对系统的盈亏影响进行分析,并对各种户型的用冷(热)负荷及能耗费用进行模拟计算.分析认为,采用"套餐"方式的收费模式,即能量费用由固定使用费用和计量使用费用两部分组成,即可以避免用户恶意用冷,造成能源浪费,又在一定程度上鼓励用户多用冷,保证系统高效率运行,减少运行成本.     

Optimal load rating-based inspection planning of corroded steel girders using Markov decision process

Steel girder bridges are vulnerable to corrosion. To maintain their safety above a predefined target level, the load rating can be computed from the inspection results and guide the following maintenance actions. Optimizing inspection and maintenance based on load ratings has substantial practical and economic relevance. Load rating-based strategies can be categorized based on whether the inspection interval and replacement criteria are fixed or flexible. Existing studies focus on fixed inspection intervals throughout the service life. In general, their results are not optimal for inspection planning. To reduce life-cycle cost, aged steel girders may be inspected and repaired in an adaptive manner. To this end, a method based on Markov decision process (MDP) is proposed to compare the life-cycle cost of four load rating-based policies (i.e. uniform or adaptive non-uniform inspection interval, and fixed or adaptive replacement threshold). Load rating-based inspection planning is formulated as MDP and the optimal plans are obtained using dynamic programming. The conventional approach to discretize states cannot accurately approximate the non-stationary deterioration process, while state augmentation is successful in doing this but will increase computational cost. A comparison of two approaches is made to investigate their effects on life-cycle cost. A bridge girder under corrosion attack is used as an illustrative example. The results show that the load rating-based plan with an adaptive non-uniform inspection interval and fixed replacement threshold obtained using the state augmentation technique can be near-optimal.