6.5MW可变速水轮发电机组的研究与设计

针对常规直流励磁水轮发电机组只能固定运行在额定同步转速下,不能随功率和水头的变化而改变机组转速的缺陷,设计了一种采用交流励磁技术的可变速水轮发电机组。发电机转子采用三相对称分布绕线式绕组设计,采用双馈式变流器为其提供三相交流励磁电流,综合自动化系统负责协调变流器和调速器之间的工作。对机组运行的测试结果表明:该机组可根据水头的变化自动调节机组转速,使得水轮机始终工作在最优单位转速附近,有效地提高了机组的运行效率、减轻了机组振动,减少了叶轮的气蚀和磨损,延长了水轮机的寿命。     

晶体管电路在WK-2型挖掘机上的应用

我厂生产的WK-2型挖掘机的电控装置采用了可控硅励磁的“发电机-电动机”系统(以下简称“F-D”系统),其系统方框图如图1所示。可控硅整流采用单相桥式全波反并联可逆整流电路。这种电路可缩短励磁绕组的过渡过程和挖掘周期。具有晶体管电路的单稳态触发器产生的脉     

采用可控硅励磁系统的同步发电机转子过电压保护装置调试

一、概述在现代同步发电机的可控硅整流系统中，当发电机组运行时，转子绕组处在突变磁场中。在正常对称运行时，转子旋转磁场和走子旋转磁场没有相对运动，转子绕组中只流过直流电流。当发电机组受到系统较大扰动时，由于电枢反应，会使转子绕组电流发生剧烈摆动，此时相当于励磁回路处于开路状态，因而转子绕组两端将产生很高的反向过电压，常常达到额定励磁电压的好几倍。在灭磁过程中，由于灭磁开关动作失灵，或者灭磁过程灭弧动作缓慢，也可能引起转子绕组的过电压。在其他情况下，例如励磁电源突然断开，或在没有续流二极管的情况下，…     

硅可控整流同步发电机励磁调节器

可控硅励磁调节器能自动保持发电机三相端电压的稳定,并具有一定的强励能力,可用于自激恒压,带励磁机的中小型交流同步发电机。该调节器与 TD_1型电压调节器相比,体积小(约为TD_1的1/4)、重量轻(约为 TD_1的1/3)、结构简单、调压精度高、反映速度快、通用性好、寿命长。主电路采用单相零式半控整流,元件过电     

谐波电流对同步发电机温升的影响分析

小容量发电机组为非线性负荷供电时,大量的谐波电流会流过同步电机的定子电枢绕组。在趋肤效应和邻近效应的影响下,高频谐波电流无法均匀分布在绕组导线截面上,而是沿绕线边缘传导。这增大了同步发电机的绕组电阻,引起发电机发热增加,效率降低,容量减小。分析谐波流经同步发电机定子绕组时趋肤效应和邻近效应的作用原理,用有限元分析软件Maxwell对电流在绕组截面上的分布规律进行仿真研究,并将绕组近似等效为若干个电感线圈,得到一种对谐波电流发热功率的估算方法。     

电压稳定的电动机励磁电源

一、概述目前,我国生产的大中型电动式挖掘机的直流电动机励磁回路和直流操作回路的电源,基本上都是采用了硅整流电路。有些矿山在对老设备改造中,也对一些老式挖掘机进行了改革,淘汰了笨重的励磁发电机,装上了简单可靠的硅二极管整流电路。但是在使用过程中发现,由于网路电压不稳或因挖掘机工作时工况不同所引起的电压变化,造成整流器的输出电     

大型抽水蓄能机组碳粉吸收装置故障分析

1工程概况 安徽响水涧抽水蓄能电站位于安徽省芜湖市三山区峨桥镇境内,单机容量为250MW的立轴单级混流可逆式水泵水轮机-发电电动机组,推力轴承置于下导轴承的油槽内,为日调节纯抽水蓄能电站.采用自并励静止整流励磁系统,额定励磁电流1 824.1A.发电机额定转速250r/min.     

运用计算机辅助分析发电机励磁控制系统

在电力系统正常运行或事故运行中,同步发电机的励磁控制系统起着重要的作用,优良的励磁控制系统不仅可以保证发电机可靠运行,提供合格的电能,而且还可以有效地提高系统的技术指标,根据运行方面的要求,励磁控制系统应该承担如下的任务:电压控制;控制无功功率的分配;提高同步发电机并联运行的稳定性;改善电力系统运行条件;水轮发电机组要求实现强行励磁。其中改善电力系统运行条件又包括:改善异步电动机的自启动条件;为发电机异步运行创造条件;提高继电保护装置工作的正确性。衡量发电机励磁控制系统的三种主要质量指标是:1稳定性电力系统在正常运行时,发电机励磁电流的变化主要影响电网的电压水平和并联运行机组间无功功率的分配。在某些故障情况下,发电机     

岩二电站发电机励磁回路接线改进

本文针对无刷励磁发电机励磁回路交流接触器烧毁的事故经过和事故原因加以分析,并提出通过改进发电机励磁回路接线,预防事故再次发生。     

发电机转子绝缘在线监测装置在水电站中的应用

在发电机的励磁回路中,绝缘最薄弱的环节就是转子部分,发电机转子绝缘在线监测装置,可用于在线监测发电机转子绕组的接地电阻以及接地点快速自动定位,快速排除故障,对保证发电机安全可靠运行具有特殊意义。     

Medium-Deep or Very Deep Disposal of Highly Radioactive Waste？

Commonly proposed concepts, like KBS-3V, for disposal of highly radioactive waste imply construction at medium depth （400-600 m） in granitic rock, which is excellent for constructing a stable repository. VDH （very deep boreholes） represent an altemative concept with the advantage that the rock is much less permeable and that the very salt, heavy groundwater is stagnant. Both require engineered barriers in the form of canisters and waste-embedding clay but for somewhat different purposes. Canisters are the most important waste-isolating barriers for KBS-3V but are less important for VDH. The waste-embedding clay is needed for preserving the KBS-3V canisters by being tight and ductile, but plays a minor role for the VDH. The backfilled deposition tunnels in a KBS-3V repository provide very limited hindrance of radionuclides to move to the biosphere while the clay seals of VDH effectively prevent possibly released radionuclides to reach up to the biosphere. Comparison of the KBS-3V and VDH concepts indicates that the last mentioned one has several advantages but that certain issues remain to be worked on for becoming a number one candidate.     

Net-Zero Energy Building Enhancement for a Leadership in Energy and Environmental Design Platinum Educational Facility

In the United States, university buildings use 17% of total non-residential building energy per year. According to the NREL （National Renewable Energy Laboratory）, the average lifecycle of a building in a university is 42 years with an EUI （energy use intensity） of 23 kWh/m^2/y. Current building and energy codes limit the EUI to 16 kWh/m^2/y for new school buildings; this benchmark can vary depending on climate, occupancy, and other contextual factors. Although the LEED （leadership in energy and environmental design） system provides a set of guidelines to rate sustainable buildings, studies have shown that 28%-35% of the educational LEED-rated buildings use more energy than their conventional counterparts. This paper examines the issues specific to a LEED-rated design addition to an existing university building. The forum, a lecture hall expansion of to an existing building at the University of Kansas, has been proposed as environmentally friendly and energy-efficient building addition. Comfort and health aspects have been considered in the design in order to obtain LEED platinum certificate. The forum＇s energy performance strategies include a double-skin facade to reduce energy consumption and PV （photovoltaic） panels to generate onsite energy. This study considers various scenarios to meet NZEB （net-zero energy building） criteria and maximize energy savings. The feasibility of NZE criteria is evaluated for： （a） seasonal comparison; （b） facility occupancy; （c） PV panels＇ addition in relation to double skin facade. The results of NZEB approach are compared to LEED platinum requirements, based on Rol （return on investment） and PV panel＇s efficiency for this specific educational building.     

The Industrial Heritage and the New Architecture： Teaching, Researching, Designing the Place Identity

The new architecture may provide unusual opportunities for the abandoned areas involved by former industrial processes, both in the city centers and in the landscape. In fact, it may create new centralities and give new collective function for deprived areas. The case study of the architectural and educational project for a new museum park devoted to the technique and the science in the Apennine＇ s landscape near Parma （Italy） may give an interesting point of view about the role of the teaching and the research of the architecture in the former industrial heritage, and to avoid the abandonment and the pauperization of the territory around.     

Guidelines for Low-Cost,Energy-Efficient House in Iraq

The goal of this study is to determine specific guidelines for Iraqi architects to contribute to the design and composition of energy-efficient housing units within the limits of a normal budget, locally available materials and technologies. These units can provide comfort despite the current energy situation in Iraq. The study is based on a computer simulation for a reference building in Baghdad, which has been selected according to the urban conditions, building legislations, housing market and statistics. The final results displayed the main recommendations and the possibility to achieve up to 50% energy reduction with a pay-back period not exceeding two years in some cases. There are some measures that have big energy saving potential. Yet, some of the measures may require big investment or have some bad environmental impacts. Some other good measures are already being implemented.     

A Case Study for End of Life Reuse and Recycling Survey Methodologies： The Hollentalanger Cottage

Up to now, reuse and recycling of existing buildings have not been examined widely. This paper discusses the theories, methods and practicalities of buildings＇ end of life with a main focus on planning and managing reuse and recycling of existing buildings. Our aim is the realistic modelling of theoretical scenarios for end of life based on a case study. The methods of building survey, material classification and documentation for reuse, recycling and disposal of existing constructions are presented. Investigations and calculations were done on an existing cottage in the Alps. The ecologically most beneficial disposal phase of the old wooden hut is our main objective. Critical questions arise from the quality of the material and how it can be extracted, separated and balanced in an appropriate way. A systematic survey of the building by inspection of constructions and materials in iterative steps allows a detailed material balance with condition and property information. This information is crucial for scenarios and material flow analysis of demolished and rebuilt building in environmental system analysis. For future planning, the reuse and recycling of existing buildings should be integrated quite early in the planning process so that we can use the materials in the best way.     

Teaching Sustainability in Design without Greenwashing

Teaching design incorporating a sense of sustainability to architecture students is a challenge today, primarily because of the trend to label every design as sustainable or green even though it is no different from a more traditional one. The result is a ＂green-washed＂ education in architecture. To address this issue, this paper describes a teaching methodology of architectural design with a special focus on sustainability implemented in the Graduate School of Architecture in Clemson. This method includes an analysis of the location, the climate conditions, the materials needed and the construction process. Knowing that sustainable design is generally perceived as being expensive, there is a special focus on simplicity and affordability. Rather than relying on expensive technical solutions, students are encouraged to design for the given environment and apply passive strategies. In the approach discussed in this paper, the design process is a number of logical scientific decisions rather than an intuitive draft. The goal of this pedagogy is to raise awareness about how to handle global resources carefully and to show the importance of the later performance of the project as a key to design. The teaching strategy is described here along with the successful participation by our graduate students in a number of refereed competitions.     

On-Demand Post-Disaster Emergency Shelters

In post-disaster emergency shelter aid, various relief agencies and other actors with different backgrounds need to cooperate in a tremendously short amount of time and under very different circumstances. In this article, we describe a research project that develops and tests a new approach in which the demands for shelters in a specific situation are methodically connected with available, innovative and sustainable shelter solutions, a DSS （decision support system）. The DSS is a digital tool that translates the gathered evidence on needs, solutions and location including long-term effects of shelter provision into advice for the provision of sustainable, integral broader shelter solutions and designs. The outcome is a set of characteristics for a DSS for the provision of on-demand emergency shelters. A DSS that meets these characteristics leads to the provision of sustainable shelters that meet the needs of the users and, therefore, have higher performance in long term.     

Fuel Poverty and Comfort in Modern Residential Apartments in Developing Countries： A Case from Jordan

Energy is one of the most important resources in the economy of developing countries. Jordan depends mainly on imported oil and gas at international prices. This creates a heavy burden upon Jordanian national economy, which is reflected in the same time on other sectors of the Jordanian society. The ever increasing fuel prices make it very necessary to look for new renewable energy resources. Jordan as a developing country with its fast growing urban development and construction projects will be studied. It is worthy to study the dynamic relationship between end user, fuel and comfort in the residential sector. Energy is a chronic problem in Jordan, due to lack of non renewable energy resources, the end consumer is influenced by this fact, in achieving his basic energy needs. This study tries to shed light on the fuel poverty line, definitions and parameters of fuel poverty. And to study what has been done in this regard on both international and local level. No studies have been identified in Jordan which, explore the problem of fuel poverty, especially after the vast and recent increase in fuel prices internationally and locally. This study will follow theoretical and field survey to understand the relationship between comfort, energy and building fabric. Method will depend mainly on field survey and statistical data, and necessary measurements, questionnaires will be adopted when necessary to explore comfort levels related to fuel consumption. Summary and recommendations will be concerned with how thermal comfort could be achieved within the ranges of fuel accessibility, building fabric, minimum pollution and cost.     

Existing Building Challenge and CONCERTO Project

If Europe is to achieve the planned transition to a low carbon economy by 2050, succeeding in improving the energy efficiency of the largely inefficient existing building stock will be pivotal. Certain energy efficiency retrofitting obligations have now emerged as part of the EU＇s Energy Performance in Buildings Directive and the Energy Efficiency Directive. Challenges for retrofitting currently include gaps in technical skills both amongst building trades and professionals, a lack of awareness of building owners and users, concerns about compromising cultural heritage as well as a lack of viable business models, comparatively high cost and resulting long pay-back periods currently hamper the progress. Lessons can be drawn here form the EU-funded initiative CONCERTO, which helped 58 communities in 23 countries to reduce their dependence on conventional energy supply by implementing energy efficiency measures and integrating renewable energy sources not at single building scale but community scale. Almost all of these entailed retrofitting activities bad to find solutions to the issues mentioned. This paper presents a selection of conclusions regarding retrofitting to be drawn from the analysis undertaken under the project CONCERTO premium, which analysed outcomes across the 58 projects on behalf of the European Commission and focuses in particular on the political relevance of outcomes.     

Images of the Future from the Past： The Metabolists and the Utopian Planning of the 1960s

During the 1960s, many changes reshaped the economy, the society and the arts. The Cold War, the Space Race, the construction of a new middle class in most western societies led by the postwar economic prosperity with unprecedented urban growth followed by severe environmental problems fostered the design of spectacular urban utopian cities and mega-architectures. In those years, Japan was the source of highly influential bold and visionary urban and architectural ideas which relied on advanced technology. These ideas were conceived on the thought that cities could be seen as gigantic but impermanent entities able to transform itself according to an organic process of adaptation of its elementary components. This paper briefly revisits and critically discusses the legacy of the iconic mega-strnctural projects of Japanese Metabolist Movement and other visionary architects and planners of the 1960s, such as Paolo Soleri, Buckminster Fuller, Archigram. It attempts to enlighten the continuity with contemporary innovative and experimental urban models and ideas for the society and the city of the future, such as the Smart Cities, Eco-Cities, Green Urbanism, whose design is led by concerns related to climate change, the necessity of energy efficiency, the improvement of urban landscape and the valorization of depleted natural resources.