软件定义电网:概念、结构与示例

针对目前电网中存在的问题,结合"软件定义"的理念,提出了软件定义电网的概念;分析了软件定义电网的特点,实现电网的管理、运行和控制的部分或全部分离;将软件定义电网分成应用定义层、运行控制层、物理设备层三层体系结构,并定义了应用定义层和运行控制层之间的北桥接口以及运行控制层和物理设备层之间的南桥接口,详述了各层及接口的功能;通过分析软件定义电网的两个应用实例,即软件定义电网在配电网中的应用和虚拟电厂中的应用,说明了软件定义电网的优势。     

基于SIMATICS7 PLC的现场总线控制系统

介绍了一种基于SIMATICS7PLC的PROFIBUS现场总线控制系统 ,具体描述了系统的构成以及组态实现。系统在逻辑结构上分为两层 :现场设备层和网络控制层 ,PROFIBUS用于现场设备层 ,网络控制层采用工业以太网。系统的组态及用户程序的编写由STEP7软件完成 ,过程的上位机监控利用WinCC软件实现。由于采用统一的开发组态软件 ,系统更容易组态、管理和维护。系统还可以接入标准以太网 ,实现生产过程的远程监控。     

变电站自动化系统中规约转换的分层结构

为了适应变电站自动化系统中各种规约的通用转换,减少软件的改动,采用三层结构的设计思想,层间接口定义完整后,若操作系统更新换代或软件功能升级,只需更改替换相应层的内容,而保持接口不变,不会影响到相邻层的实现.     

基于Qt的电力系统地理接线图绘制软件设计

针对PSD-BPA的地理接线图绘制软件存在的缺陷和不足,提出了一种以Qt库为基础的电力系统地理接线图绘制软件设计方法。首先,按照软件的功能需求,以及各模块间相互独立、视图数据相互分离的设计思想将软件划分为3层结构:数据服务层、绘图操作层和辅助功能层。然后,以Qt图形视图框架为基础建立了软件的主体绘图框架,并详细阐述了数据库视图框架、潮流动画功能以及接线图输出技术的实现方法。     

变电站自动化系统中规约转换的分层结构

为了适应变电站自动化系统中各种规约的通用转换,减少软件的改动,介绍了一种采用三层结构的设计思想,层间接口定义完整后,若操作系统更新换代或软件功能升级时只需更改替换相应层内的内容,而保持接口不变,不会影响到相邻层的实现.该方法具有较高的应用价值.     

基于Qt的电力系统地理接线图绘制软件设计

针对PSD-BPA的地理接线图绘制软件存在的缺陷和不足,提出了一种以Qt库为基础的电力系统地理接线图绘制软件设计方法.首先,按照软件的功能需求,以及各模块间相互独立、视图数据相互分离的设计思想将软件划分为3层结构:数据服务层、绘图操作层和辅助功能层.然后,以Qt图形视图框架为基础建立了软件的主体绘图框架,并详细阐述了数据库视图框架、潮流动画功能以及接线图输出技术的实现方法.     

数字卫星电视接收机软件的组成原理

一、数字卫星电视接收机的软件结构从设计上讲,数字卫星电视接收机的完整组成,应分成软件和硬件两大部分。通常软件由三层组成,其每一层均充分反映了数字卫星电视接收机硬件的高档次的功能并使其抽象化,还有一个通用的支持框架贯彻所有档次。每一层中还可分成若干模块,用户使用这些     

高压电机绕组电缆特性研究

介绍了新型电缆绕组高压电机并分析了绕组电缆的结构及特性,为解决绕组电缆外半导电层局部温升过高的问题,首先利用ANSYS软件仿真分析外半导电层的电场和磁场耦合场,确定了温升与接地电流的关系,然后采用PowerSim软件研究了外半导电层电阻对系统的影响。研究表明,外半导电层的电阻、接地电阻分布是决定其温升的关键因素。最后综合其它条件给出了外半导电层的合理电阻范围。     

浅谈计算机多层软件的应用

随着时间的推移而不断的增长，计算机技术的迅猛发展，以及计算机软件的广泛应用也是日新月异，随着业务拓展以及社会需求的增多，计算机在软件的设计和开发过程中越来越重要，多层软件的应用也凸显其重要地位。本文将针对计算机软件方面的问题进行了一些表述与探讨，进而具体分析多层软件的应用。     

电力电缆温度场与载流量计算软件设计

针对电力电缆温度场的仿真问题和载流量的计算问题,基于有限元方法和等效热阻法开发了电力电缆温度场与载流量计算软件。软件采用面向对象的Visual C#语言以及Microsoft Visual Studio平台上的Windows Presentation Foundation技术,具有高度模块化的视图层、控制层和模型层三层软件架构。该软件实现了电缆载流量的解析计算与数值计算、电缆温度场的数值分析及其数据可视化等功能,并使用电缆厂的技术数据对软件的计算准确性进行了测试。与其他商业软件相比,该软件在电缆参数计算领域更具专业性,而且节省了建立电缆有限元模型的时间。     

Control of shrinkage on the behavior of co-firing of ferrite and varistor multi-layers composite with organic content

When make multi-layer ceramics device such as EMI filter, there are a lot of process problems. Specially, crack, camber and delamination should be controlled surely by different sinter shrinkage rate of interface of two materials. The purpose of this work was to co-fire defect-free ferrite/varistor ceramic multi-layers fabricated via a calcination temperature and organic vehicle contents of ferrite. Sintering shrinkage of both calcined ferrite and varistor materials were measured using dilatometer. X-ray diffraction analysis indicated that no significant phase change occurred in the materials under investigation as a result of the sintering process. Crack and delamination of each interface were observed by scanning electron microscopy and optical microscope. We obtained the defect-free and co-fired ferrite/varistor ceramic multi-layer by controlling calcinations temperature.     

A study of delamination growth in the die-attach layer of plastic IC packages under hygrothermal loading during solder reflow

This paper describes a comprehensive numerical study of the effects of many parameters on the propagation of delaminations in the die-attach layer using a finite element linear elastic fracture mechanics approach. An 80-pin plastic quad flat package of dimensions 20 mm/spl times/14 mm/spl times/2.7 mm was considered. The parameters investigated include the coefficient of thermal expansion (CTE) of the die-attach material, the thickness of the die-attach layer, the CTE of the pad material, and the size of the initial delamination (defect). The effect of the location of the initial delamination was studied by considering delaminations at the center, edge, and quarter-point locations along the pad/die-attach interface. The effect of swelling of the encapsulant due to moisture absorption during preconditioning at 85/spl deg/C/85%RH was also considered. The combined effect of the hygrostress and thermal stress developed during solder reflow was obtained by suitably superimposing the respective stress intensity factors. The effect of the pressure of water vapor at the delamination was also investigated and found to be negligible for small delaminations. This study has shown that the propagation of delamination from an initial defect located at the edge of the pad/die-attach interface is unstable. Once delamination propagates, it will continue until the entire interface is completely delaminated.     

调度自动化系统实时信息分层分流构建

为了满足调控一体化对信息自动化的要求,依据《宁夏地区电网调控一体化信息规范》,对石嘴山供电局调度自动化系统实时信息告警模块进行了改造,实现了信息的纵向、横向分层及分流处理,应用结果表明：经过有效分流、分层处理后,系统满足了电网各类调度生产人员对自动化信息的需要。对整个电网的安全、经济运行起到了积极的作用。     

750 kV油浸式电抗器套管升高座热像分层原因分析

在某750 kV变电站红外精确测温发现I线750 kV油浸式电抗器高压套管升高座有明显红外热像分层现象,表面温度判断法、同类比较判断法判断I线电抗器套管升高座位置疑似存在缺陷.经局部放电检测排除内部缺陷或故障,热学理论和Fluent软件流体温度场仿真分析判断I线电控器升高座红外热像分层原因是由于发热量大且结构紧凑引起散...     

Nondestructive inspection of thermal barrier coating of gas turbine high temperature components

A thermal barrier coating (TBC) is applied to high‐temperature components in gas turbines, and consists of a ceramic topcoat and a metallic bondcoat. Various kinds of TBC degradation and damage occur in high‐temperature components during service, such as topcoat thinning, topcoat delamination, and formation of a thermally grown oxide (TGO) layer below the topcoat, each of which can be examined using a suitable nondestructive inspection technique. Topcoat thinning can be detected by topcoat thickness measurement using terahertz waves, which are electromagnetic waves in the frequency region between optical and radio waves. The measurement resolution is about 10 μm, which is comparable to microscopic observation of the cross section in destructive inspection. Topcoat delamination can be detected by active thermography, in which the topcoat surface is scanned by a heating laser and the surface temperature distribution is measured by a thermal infrared camera. The combination of temperature peak and residual thermal image detection is effective in eliminating false detection. The TGO layer can be detected using photoluminescence, in which the Cr³⁺ ions included as an impurity in Al₂O₃ are detected. Since delamination tends to occur at locations at which the TGO layer has grown, TGO layer detection provides an effective method to select regions where delamination has occurred or is likely to occur. An inspection flow based on these techniques is proposed, which is expected to aid the establishment of condition‐based maintenance strategies of high‐temperature components. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Moisture-Induced Delamination in Plastic Encapsulated Microelectronic Devices: A Physics of Failure Approach

By identifying the moisture concentration at the weakest material interface as the critical parameter for the defect onset, the quantitative prediction of moisture-induced delamination between the molding compound and die surface in plastic packages was realized using a simple 1-D diffusion model. As a result, the delamination onset during multiple soak and reflow procedure, as prescribed by customers' specifications, was predicted from the IPC/JEDEC J-STD-020C moisture sensitivity level. For the case studied here, the soldering peak temperature had the most significant influence on the moisture sensitivity of the package. The remaining part of the soldering temperature profile (ramp up and down) was found to have a rather small influence.      

On Wire Failures in Microelectronic Packages

At present, over 95% of the manufactured packages are still being wire-bonded. Due to the ongoing trend of miniaturization, material changes, and cost reduction, wire-bond-related failures are becoming increasingly important. Different finite-element (FE) techniques are explored for their ability to describe the thermomechanical behavior of the wire embedded in the electronic package. The developed nonlinear and parametric FE models are able to predict the strong nonlinear behavior of wire failures and multifailure-mode interaction accurately and efficiently. It is found that both processing and reliability-testing environments as well as the occurrence of delamination strongly increase the risk of wire failures. Our results indicate that processing and reliability-testing influences are much less than those of the delamination. Combining the strengths of predictive modeling with simulation-based optimization methods, the optimal wire-loop shape is obtained.      

风机叶片材料雷击热损伤特性及损伤机制的分子动力学研究

随着风力发电的发展,风机面临愈加严峻的雷击风险。该文对2种常用叶片材料实际成分进行计算并据此建立分子体系模型,采用分子动力学研究手段对其进行雷击损伤的定量研究,揭示其热解损伤、气体膨胀损伤和机械强度损伤特征。分子动力学研究结果表明轻木具有更好的热稳定性、更高的刚度,并受气体膨胀损伤最小。对2种夹层材料的风机叶片样本进行大电流冲击实验印证了分子模拟的结果。但实验显示轻木叶片样本的分层现象更明显,主要因为材料结构孔隙大降低了粘合度。综上所述,轻木相较于PVC具有更好的热稳定性和更强的耐雷击能力,但制作夹层材料时应提高粘合度,以削弱雷电弧热效应造成的分层现象。     

Effects of Temperature Cycling and Elevated Temperature/Humidity on the Thermal Performance of Thermal Interface Materials

Thermal interface materials (TIMs) have become increasingly important in reducing the interfacial thermal resistance between contacting surfaces inside electronic devices, such as at the die–heat-sink or heat-spreader–heat-sink interfaces. While the focus regarding implementing TIMs remains on reducing the thermal resistance path, the long-term performance of the TIM is important from a life-cycle standpoint. This paper presents test and analysis results examining the effect of temperature cycling and elevated temperature/humidity on the thermal performance of filled polymer TIMs using the laser flash method. A three-layer sandwich structure was used to simulate loading conditions encountered by TIMs in actual applications and to assess the change in their thermal resistances. The evaluated thermal resistance included contact and bulk resistances and was calculated using the Lee algorithm, an iterative method that uses the properties of the single layers and the three-layer sandwich structures. Test samples included three thermal putties, a gap filler, an adhesive, a gel, and two gap pads. For most materials, little change or slight improvement in the thermal performance was observed over the course of environmental exposures. Scanning acoustic microscope images revealed delamination in one group of gap pad samples and cracking in the putty samples as a result of temperature cycling. One thermal putty material showed degradation due to temperature cycling resulting from bulk material changes near the glass transition temperature, while other samples showed little change or slight improvement in the thermal performance over the course of temperature cycling.      

北京电网分层分区与调度运行分析

根据北京电网、上海电网年度运行方式报告,结合电网规划理论与国内外电网规划运行经验,对北京、上海电网网架结构、电源布局、设备利用情况进行了分析。从电网规划、电网建设、电网调度系统建制、电网分层分区运行可行性等方面,对北京电力系统电网现有网架结构进行具体分析,总结了目前北京电网规划及分层分区运行中存在的问题,并就北京电网调度系统地调建制调整、电网规划、电网分层分区运行提出一些可行性意见。通过对北京调度系统地调建制调整两种方案的比较分析,提出了关于北京电网调度系统建制调整一种可行性方案。最后结合国内外电网发展趋势对北京电网未来规划及分层分区运行进行了展望。