电力变压器的动稳定

在变压器短路电动力的计算中,目前是以静态力代替动态力的方法来进行的。这不能适应变压器机械强度的要求。针对此问题,从电动力的基本理论出发,建立起变压器的动态数学模型,对变压器在短路电流作用下线圈产生的动态力进行了理论分析和计算,对在短路电流作用下的变压器线圈(器身)绝缘结构进行了初步研究,提出了动稳定的计算方法。     

有关SF_6电器标准问题的探讨

SF6气体作为绝缘介质广泛用于变压器、开关装置及电力电缆等高压电器中，就涉及SF6中水分及分解物的标准问题，包括标准自身以及执行标准等进行探讨。     

冷环境下织物保暖性研究

本文研究了冷环境下的织物保暖性。在实验的基础上,对织物的原料、厚度、环境温度、组织等诸因素与热阻的关系作了分析,比较了诸因素对热阻的影响状况,并得到一系列关系图。为新产品在保暖性方面的相关设计提供了依据。     

大型直流电机采用少胶粉云母箔卷包绝缘结构及效益分析

本文通过大型直流电机全部采用单面玻璃布补强少胶粉云母箔卷包的绝缘结构(简称全粉卷包结构)与我厂目前大型直流电机常用的多胶粉云母带,簿膜混合绕包绝缘结构的对比分析,说明全粉卷包结构具有良好的电气性能、经济效益和社会效益.     

Solar optical materials for innovative window design

New and innovative optical materials and coatings can greatly improve the efficiency of window energy systems. These potential materials and coatings increase energy efficiency by reducing radiative losses in the infrared, or reducing visible reflection losses or controlling overheating due to solar gain. Current progress in heat mirror coatings for glass a polymeric substrates is presented. Highly doped semiconducting oxides and metal/dielectric interference coatings are reviewed. Physical and optical properties are outlined for antireflection films and transparent aerogel insulation media. The potential for optical switching films as window elements includes discussions of electrochromic, photochromic and other physical switching processes.     

Vacuum Insulation Panels (VIPs) for building construction industry – A review of the contemporary developments and future directions

Demand for energy efficient buildings has increased drastically in recent years and this trend will continue in the future. Insulating building elements will play a key role in meeting this demand by reducing heat losses through the building fabric. Due to their higher thermal resistance, Vacuum Insulation Panels (VIPs) would be a more energy efficient alternative to conventional building insulation materials. Thus, efforts to develop VIPs with characteristics suitable for applications to new and existing buildings are underway. This paper provides a review of important contemporary developments towards producing VIPs using various materials such as glass fibre, foams, perlite and fibre/powder composites. The limitations of the materials currently used to fabricate VIPs have not been emphasised in detail in previous review papers published. Selection criteria, methods to measure important properties of VIPs and analytical and numerical models presented in the past have been detailed. Limitations of currently employed design tools along with potential future materials such as Nano/microcellular foams and SiO_x/SiN_x coatings for use in VIPs are also described.     

Modelling of a thermal insulation system based on the coldest temperature conditions by using artificial neural networks to determine performance of building for wall types in Turkey

In formation of building external envelope, as two important criteria, climatic data and wall types must be taken into consideration. In the selection of wall type, the thickness of thermal insulation layer (d_i) must be calculated. As a new approach, this study proposes determining the thermal insulation layer by using artificial neural network (ANN) technique. In this technique five different wall types in four different climatic regions in Turkey have been selected. The ANN was trained and tested by using MATLAB toolbox on a personal computer. As ANN input parameters, U_w, T_e,Met, T_e,TSE, R_wt, and q_TSE were used, while d_i was the output parameter. It was found that the maximum mean absolute percentage error (MRE, %) is less than 7.658%. R² (%) for the training data were found ranging about from 99.68 to 99.98 and R² for the testing data varied between 97.55 and 99.96. These results show that ANN model can be used as a reliable modeling method of d_i studies.     

Evaluating the Sensitivity of Attic Radiant Barrier Performance to Climate Parameters

By employing a calibrated and tested computer model, simulations of ceiling heat transfer in typical residential attics located in 12 locations across the United States were obtained to study the sensitivity of attic radiant barrier performance to local climate parameters. For each location, the net ceiling heat flux over the summer cooling season was computed for an attic with and for an attic without an installed radiant barrier. The net reduction of heat flux induced by the radiant barrier was computed and then related to climate variables. Among the local environmental parameters, the local ambient air temperature, local ambient humidity, and latitude had significant effects on the performance of radiant barriers. It was concluded that the installation of radiant barriers would be most beneficial in regions with high outdoor air temperatures and high relative humidity.     

有关变频器驱动电动机中浪涌对策的基础研究

变频驱动的电动机,为满足节能及小型化、高性能化等市场需求,必然要面对严酷的使用条件,其中,变频器产生的浪涌(surge)对电动机绝缘系统会产生不利影响。"明电"公司在掌握变频器浪涌对电机影响的同时,使用了耐局部放电性能优越的漆包线。针对该绝缘系统的适用性进行了不断的探索研究。     

Prediction parameters of dimensioning of insulators under non-uniform contaminated conditions by multiple regression analysis

Surface tracking on solid insulators is one of the most severe breakdown mechanisms. Accurate assessment of real insulation conditions can be achieved by using the statistical techniques that assist the measurement and monitoring of contamination severity, flashover voltage and leakage current.To address the uncertainties that surround the exact physical mechanisms underlying the mathematical models, it has been shown that it is possible to include in the assessment of insulator performance contamination accumulation that is predicted by using a short historical of chemical components and atmospheric conditions. The results from this work are useful to predict the contamination severity, flashover voltage as a function of contamination severity, leakage current as a function of applied voltage, arc length and contamination severity, and especially to predict the flashover current.