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(一) 前言水轮机的额定水头(水轮发电机组发出额定功率时的最小水头)如选择不当,将直接影响水电站的建设投资与发电经济效益。因此,对水轮机的额定水头应根据水电站的水能特性进行多方案比较,选择最优的额定水头。中小型水电站多数为径流引水式,以往对这这种径流引水式水电站的水轮机额定水头有不少是选择不适当的,因而使选用的水轮机型号、转轮直径、额定转速等与水电站的运行特征不符,造成水轮 相似文献
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水电站额定水头是水轮机组发额定容量时相应的最小水头,其选择是一个技术、经济等综合性问题.最佳的额定水头必须在满足稳定的前提下,通过经济技术综合比较,分析水轮机预想出力降低对电力系统平衡的影响等综合分析确定.文章重点介绍了大中型水电站额定水头的选择方式、方法. 相似文献
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水电站额定水头的选择是一个技术、经济等综合性问题。针对几内亚苏阿皮蒂水电站额定水头的确定,若额定水头较高,当机组长时间低于额定水头运行时,会造成较大的受阻容量;若额定水头较低,机组存在运行稳定问题,且在额定容量不变时,需加大水轮机直径或相应降低机组转速,从而增加投资。结合国内相同水头段已建水电站的设计、运行资料综合分析,确定苏阿皮蒂水电站额定水头为87 m。 相似文献
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确定一个合适的水轮机额定工作水头,对于保障水轮发电机组的稳定运行和提高水电站运行的经济效益是至关重要的。以立州水电站水轮机选型设计为例,通过对不同额定水头方案水轮机的加权平均效率、投资、运行可靠性等的分析和比较,阐述了确定水轮机额定水头时应考虑的主要因素和优选方法。 相似文献
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在水电站的设计中,额定水头的选取是关系水电站稳定运行的重要因素。黄花寨水电站最高水头90.47 m,最低水头59.48 m,针对水头变幅大这一特点,对水轮机的额定水头选取进行综合的技术经济比较,对水头出现频率分析后,得出适合电站运行的额定水头。并提出了从参数选择、水头范围、吸出高度控制、避振运行、补气方式等提高机组运行稳定性的措施。 相似文献
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混流式水轮机电站运行稳定性与装机容量选择的探讨 总被引:2,自引:0,他引:2
当前电力系统希望水电站能以较高的保证率发足装机容量,也就是要求较低的额定水头;但从混流式水轮机稳定的要求出发,希望额定水头、设计水头都不能低于Hmax/1.1,怎样才能既满足电力系统的要求又能使水轮机稳定运行呢。建议采取提高额定水头,增加机组台数或加大单机容量的方式来协调解决。 相似文献
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额定水头既是水轮机的重要参数,也是电站的重要动能参数。从水轮机运行特性、动能经济指标、统计成果及机组制造可行性等方面出发,介绍了双江口水电站额定水头的选择成果,并论述了发电机不设最大容量的可行性。 相似文献
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雷公滩水电站属于低水头水电站,其水库仅具有日调节性能,因此,机组型式的选择及额定水头的确定将会直接影响到整个工程的投资规模和后期的经济效益。综合考虑该水电站处于交界水头的实际情况,通过对不同机型的投资、能量特性等方面展开分析,对不同额定水头方案下水轮机的运行稳定性、经济效益等方面的参数进行比较,最后确定雷公滩水电站采用灯泡贯流式机组,额定水头选取为14.53 m。 相似文献
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抽水蓄能电站水泵水轮机水轮机工况额定水头的确定直接关系到电站运行的稳定性和经济性,而它的选择与常规电站水轮机额定水头的确定既有相似之处、又有不同之处,本文通过对惠州抽水蓄能电站水轮机工况额定水头的选择,介绍抽水蓄能电站水轮机工况额定水头的选择应考虑的问题,为今后抽水蓄能电站水轮机工况额定水头的选择提供参考。 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