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SWTA自动励磁装置增设欠磁保护望亭发电厂龚金和增设欠磁保护的原因SWTA自动励磁装置中的低励限制器,其作用是防止测量系统误发低励信号。而该装置原设计没有考虑防止限制器误限制的措施,当Ⅰ段和Ⅱ段瞬时电流限制器、强励限制器、伏/赫限制器误发限制信号时仍... 相似文献
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本文研究了低励限制的作用和存在的问题。文中阐明了具有良好性能的调节器(包括PSS)的快速励磁系统,不采用低励限制器可以吸收更多的无功。数字仿真是研究励磁系统性能和选择低励限制的有效工具。 相似文献
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1 低励限制器的工作原理低励限制器的方框图如图1所示。机端图1 低励限制器的方框图电压U_F,静子电流I_F经动作分量形成器和制动分量形成器后,分别输出动作分量V_(dz)=|k_1U_F+k_2I_Fe~(j(90+(?)))|及制动分量U_zd 相似文献
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电网实际运行中多次发生因发电机低励限制功能设置不当导致机组运行异常甚至掉机的严重后果.分析了低励限制的应用目标,比较了不同类型低励限制器的功能特点.将低励限制的性能要求划分为静态和动态两方面,提出了相应的设置原则:静态,性能遵循在有功出力全范围合理定义,满足定子端部热稳定,满足系统静稳定、根据机端电压变化调整、与失磁保... 相似文献
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分析了过励限制器的功能特点和设计要求,提出了向家坝水电站800MW发电机过励限制器模型。通过RTDS仿真试验和动态数据分析,总结了过励限制器与过励保护、强励限制和发电机过负荷保护配合的技术特点,对大容量发电机组过励限制器应用提供了借鉴和参考。 相似文献
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电网实际运行中多次发生因发电机低励限制功能设置不当导致机组运行异常甚至掉机的严重后果.分析了低励限制的应用目标,比较了不同类型低励限制器的功能特点.将低励限制的性能要求划分为静态和动态两方面,提出了相应的设置原则:静态,性能遵循在有功出力全范围合理定义,满足定子端部热稳定,满足系统静稳定、根据机端电压变化调整、与失磁保护协调配合原则设置限制线;动态性能遵循保证控制系统稳定性、优选控制结构、防止严重影响PSS作用、避免暂态期间不必要动作原则优化控制器结构和参数. 相似文献
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发电机励磁调节器低励限制协调控制分析 总被引:1,自引:0,他引:1
从原理上分析了低励限制器(under excitation limiter, UEL)参数整定不当导致系统阻尼弱化的原因,指出了 UEL提供的电磁转矩在Δω方向的分量滞后Δω180°,以及 UEL的作用频段与 PSS 配合不当是产生机组阻尼弱化现象的主要原因,并在 PSS/E 和 Matlab 仿真软件中建立了单机-无穷大系统的励磁控制系统自定义模型,通过仿真验证了理论分析结论.仿真结果进一步表明 UEL 提供负阻尼转矩时,低励稳定曲线斜率越低,UEL 的作用频段越低,系统时域动态响应特性越好. 相似文献
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工程档案的价值与作用如何体现,一直是档案界争论的课题。长期以来,重视工程实体建设,轻视工程档案及档案管理工作的重要性,对于档案工作的人力、物力投入不够,工程档案电子化进程较慢,工程档案管理工作未全面纳入企业生产经营活动的议事日程。本文就此进行浅述,意在提高对工程档案的认识和归档自觉性。 相似文献
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This paper reviews the economic literature that, for policy evaluaton purposes, assigns a value to risking human lives. It argues the ethical justification for evaluating risk by observing how much people are willing to pay personally to avoid risks. Most willingness-to-pay figures are based on observations of how much compensation workers must be paid to work at a risky job. The conceptual and practical problems and biases in these figures are explained. The main studies of financial value of life calculation are reviewed in light of this discussion. The review concludes that a conservative estimate for the value of risking a life is $8 million (1984 dollars), a figure far greater than is typically used in policy analysis. Policy-makers are often required to weigh the benefits of instating safety precautions in a project or policy alternative against its costs. Making these tradeoffs requires an evaluation of the alternative relative risk, i.e., a translation of potential risks into dollars and cents. In this article, I will summarize and critically review from an economist's point of view the literature on the dollar value of risking life?the ``value of life (VOL)'?concentrating on the literature written by fellow economists. Evaluation of nonfatal injury and illness is just as critical a part of risk evaluation; however, space constraints prevent me from including it in this discussion. VOL figures are not meant to be equivalent to what you would pay in ransom money to a kidnapper in order to save your life. 相似文献
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科学发展观把以人为本作为其本质与核心,将以人为本渗透于全面、协调、可持续发展之中,深刻揭示了社会主义现代化建设的价值目标、价值主体、价值导向,有利于我们完整、准确地对社会主义现代化的价值内涵进行把握. 相似文献
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思想政治教育能够满足受教育者成长和发展的需要,具有个体价值.但是,其个体价值只有在实现中才能成为真正的价值.思想政治教育个体价值的实现并不是轻而易举的,而是一个复杂的过程.因此,我们需要采取科学而有效的途径,切实实现思想政治教育的个体价值. 相似文献
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在燃煤价格高企及电煤价格倒挂等因素影响下,为降低发电成本,燃煤火力发电厂普遍采取扩大燃用煤种范围的燃煤掺烧策略。降低燃煤品质可以实现综合标煤单价下降,提升发电项目的盈利能力。研究了燃煤品质的2个主要参数——发热量和硫分对发电成本的影响,构建了基于发热量和硫分的发电成本模型,可为发电企业燃煤掺烧成本测算提供有益参考。 相似文献
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《Education, IEEE Transactions on》1964,7(4):161-165
Because of the exponential growth of science and technology, the engineering student cannot hope to take more than a small sub-set of the many engineering courses available to him. The question often arises about the degree to which engineering students should find room in their cramped study schedule for work in the humanities, the social sciences, and other nonengineering topics. The engineer is faced with making value decisions in the realistic practice of his profession. In this paper, it is shown that making value decisions is inherent in the design process itself. It is also shown that the engineer's position in modem society is often at the right hand of major decision makers. Since many engineers are in a position where they cannot avoid sharing responsibility for decisions affecting social, political, and economic change, serious training in these areas appears desirable. 相似文献