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为了提高计算机监控系统的可靠性,根据监控系统结构和形式的不同,将其系统安全性、可靠性的冗余方式归纳为电源冗余、控制器冗余、输入/输出冗余和通信冗余,以及应用软件的安全与冗余等方式。文中对龙羊峡水电厂计算机监控系统可靠性的冗余方式作了详细介绍。 相似文献
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为了提高计算机监控系统的可靠性,根据监控系统的结构和形式不同,其系统安全性、可靠性的冗余方式大致可归纳为电源冗余、控制器冗余、输入/输出(I/O)冗余和通信冗余以及应用软件的安全与冗余等方式。本文就龙羊峡水电厂计算机监控系统可靠性的冗余方面作了详细的介绍。 相似文献
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通过对三冗余、双冗余和无冗余励磁调节器工作方式故障概率的计算,比较这3种工作方式在正常调节、部分拒调和完全拒调情况下的正确调节概率,得出三冗余励磁调节器的优缺点,提出了改进方案,可供选型设计参考. 相似文献
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为了提高计算机监控系统的可靠性,可根据监控系统不同的结构和形式,将电源冗余、控制器冗余、输入/输出(I/O)冗余和通信冗余以及应用软件的安全与冗余等方式改善并优化 相似文献
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分析了将变电站集中监控系统与能量管理系统(EMS)建成双核冗余的一体化系统的必要性和可行性,阐述了具体实施方案,以及双核冗余系统中的数据采集、图形数据展示、应用资源管理、商用库自动同步等原理。该设计能够确保EMS和变电站集中监控系统的可靠性。 相似文献
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根据大型水轮机调速器的高可靠性要求,探讨了其冗余方案。该冗余方案主要涉及测频、微机调节器、电液转换部件、位移传感器、电源系统等环节。对每个环节的冗余进行了展开分析,对完全并列的热备用冗余和互相交叉的热备用冗余的优缺点进行了比较。根据机组在电网中的不同地位和实现的可行性与必要性,选择采用合适的冗余方式。结合实际应用进一步阐述了冗余方案的配置方法。 相似文献
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以广州蓄能水电厂B厂RTU可编程序控制器(PLC)冗余配置为例,概要的介绍了PLC冗余配置的基本方式、工作原理和过程、以及多种工作状态之间的转换,简要地介绍了广蓄B厂冗余PLC的应用运行情况。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献
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简述天湖水电站投运以来各种故障的表现形式,分析其原因,提出了相应的处理方法及措施,并对合理利用国内外设备提出建议。 相似文献