电力电子和未来的航海电气系统(上)

明天的航海电气系统将同今天的系统有极大的不同。电力电子给予船舶上包括推进、电力分配、备用电源、声纳和雷达等在内的各种系统的进展以重要的影响。刚刚出现的新材料、新器件和新的系统概念(诸如宽带半导体材料、碳化硅基的电力半导体器件、电力电子模组(PEBB),以及集成功率系统)正在使、并将持续地使未来的航海系统有别于今天的系统,如同内燃船舶有别于蒸汽船舶。但是,这些正在实现的技术和有关概念还未被大家所周知,而且还有难于理解的地方。本文就将介绍这些新概念和新技术,指出潜在的影响力,并揭示新的设计方法,以推动航海电气系统的发展。     

基于级联网络的电力系统短期负荷预测

电力系统短期负荷预测对电力系统运行设计具有十分重要的意义。因此，在分析了电力负荷运行曲线的基础上，提出了一种基于级联模糊神经网络的预测模型。该模型采用基于神经网路理论的模糊模型参数辨识方法，很适合于复杂系统的模糊预测和控制。详细地对输入量的选择和学习算法进行了分析。实例表明，此方法具有町靠、鲁棒性好和快速等特点，优于神经网络电力负荷预报方法。     

基于测度贴近度的电子剪切散斑轮胎检测

本文把测度贴近度的概念引进到电子剪切散斑检测中,提出了一种基于测度贴近度的条纹形成算法。该算法大大地消除了条纹可见度对光照强度的依赖,提高了电子剪切散斑无损检测对工业环境的适应性,并且该算法可以在条纹产生的同时对其进行滤波,减轻了后续工作。本文从数学分析和实验两个角度证实了该算法的以上特点。     

热轧板常化温度对冷轧无取向电工钢退火组织和磁性能的影响

研究了≤0．005％C-2．5％-2．8％Si的2．5mm热轧电工钢板在850—1100℃常化对0．5mm冷轧板880℃＋950℃退火后组织和磁性能的影响。结果表明，热轧板常化温度升高，冷轧板退火后的再结晶晶粒增大，铁损降低，磁感呈单调递增趋势；热轧板常化温度超过1000℃，因第2相固溶而后弥散析出，退火冷轧晶粒细化，铁损增加，因此该钢热轧板最佳常化温度为1000℃。     

改善道路质量以提高电动轮轮胎的使用寿命

通过对影响露天矿山电动轮轮胎使用寿命的因素分析,发现了改善道路质量,同时加强对电动轮轮胎运行、装配和检查等现场管理,是提高电动轮轮胎使用寿命,降低电动轮轮胎消耗,从而降低矿山采矿成本的有效途径之一。     

100吨电炉自动控制系统设计及改进

本文介绍了安钢100吨电炉两级自动控制系统的设计方案，详细阐述了一级、二级自动控制系统的配置和功能，对于系统运行中出现的问题，提出了改进方案。     

6500m~3/h空分设备分子筛纯化器电加热器改造

介绍了6 5 0 0m3 /h空分设备分子筛纯化器新配电加热器电加热管烧断的故障现象,分析了故障原因,后通过增加气体挡板解决了问题;并通过改造,既达到了分子筛纯化再生的技术要求,又实现了电加热器的一用一备     

Impact of Phase Shifters on Locational Prices

With the introduction of restructuring in the electric power industry, the price of electricity has become the focus of power market activities. Phase shifters in a power system can mitigate or reduce transmission congestion by redirecting line flows, reduce the cost of power dispatch by adjusting locational marginal prices (LMPs), and enhance market competition by reducing the chance of market power occurrences due to limited transmission flows. This paper analyzes the role of phase shifters in restructured power systems by simulating electricity market prices. The paper further provides a comparison among various alternatives such as transmission expansion for mitigating congestion. The simulation results are analyzed for a three-bus and presented for the Institute of Electrical and Electronics Engineers (IEEE) 118-bus power system.     

Effect of electric charge accumulation on low energy ion implantation in insulators

Charge accumulation at the surface of insulators during low energy ion implantation is related to two processes: ion impinging on the sample and secondary electron emission. Samples composed of a piece of Si (having the size of the ion beam) fixed on the centre of polyethylene (PE) coupons have been implanted with 2.2 keV H₂ ions to a fluence of 2 × 10¹⁶ H/cm². ERD (Elastic Recoil Detection) depth profiles of the implanted ions are shallower with an increase of the PE coupon size. The relative critical Si/PE size to repel all the incident ions is around 1.1 × 1.1 cm²/2.5 × 2.5 cm². The potential of the secondary electron suppressor has been varied from −500 V to +500 V. It changes the secondary electron distribution around the implanted area and, consequently, affects the accumulation of charges at the sample surface. When the potential is 0 V, a uniform ion implantation with little effect of charge accumulation for all sizes of PE coupons is obtained. A two-dimension model has been performed and gives a good explanation for the mechanism of the electric charge neutralisation.     

Soot and other Products Formation from the Submerged Carbon Arc in Halogenated Solvents

A series of selected halomethanes were treated with the submerged carbon arc using graphite electrodes at 10A. CCl₄ and CHCl₃ produce abundant soot which is double in comparison to the soot produced by arcing CH₂Cl₂ and is one order of magnitude higher than the amount of soot produced by arcing hydrocarbons such as n-hexane or decalin and two orders of magnitudes higher in comparison to the amounts of soot produced by arcing alcohols. It was found a anticorrelation between the amount of polyynes present in the solution of the arced solvent and the amount of soot produced by arcing. In the case of CCl₄ and CHCl₃ no polyynes were detected by liquid chromatographic analysis (HPLC-DAD), while polyynes were detected in CH₂Cl₂ and are present in higher concentration in arced hydrocarbon solutions. The soot produced from halomethanes was analyzed by FT-IR spectroscopy in comparison to the soot produced by arcing hydrocarbons and alcohols. Furthermore, the soot from halomethanes was analyzed by HPLC-DAD after extraction with acetonitrile and found to contain a mixture of halogenated polycyclic aromatic hydrocarbons (PAHs). Also CHClBr and CH₂I₂ were arced between graphite electrodes. The former compound produces free bromine and soot; bromine causes halogenation of the polyynes. In the case of the latter compound, free iodine is released from the arc and the amount of soot produced is comparable to that obtained by arcing CH₂Cl₂.