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分析了高压电气设备绝缘系统在多种应力联合作用下的老化规律,提出了相应的寿命模型。概述了基于绝缘老化在线检测的状态维修的必要性、实现方法和当前的研完状况。 相似文献
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分析了高压电气设备绝缘系统在多种应力联合作用下的老化规律,提出了相应的寿命模型。概述了基于绝缘老化在线检测的状态维修的必要性、实现方法和当前的研究状况。 相似文献
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绝缘在线监测系统运用当代先进的电子技术,分析电气设备运行过程中绝缘参数的变化,判断电气设备的老化程度和是否存在缺陷,实现了绝缘状态的远程、离线监测,为电力生产提供了可靠的监测手段,为设备的状态检修提供了有力的依据。二滩电厂在运用绝缘在线监测装置的过程中,获得了一些经验,达到了一定的效果。 相似文献
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电气设备局部放电信号的特征提取是电气设备绝缘在线监测及故障诊断技术领域的前沿课题。当前的研究大多集中在交流局部放电的特征提取方法上,很少有人研究直流局部放电的特征提取方法。文中采用移动时间窗技术,提出一种新的直流局部放电特征提取方法。该方法通过研究时间窗内的局部放电次数、最大视在放电量、平均视在放电量等物理量与电气设备绝缘状态之间的关系,提取它们作为表征电气设备绝缘性能的特征量,用来进行状态评估与故障诊断。实验结果表明,该方法所提取的特征量能够很好地表征电气设备的绝缘性能,为电气设备绝缘的在线监测提供了理论依据。把它应用于地铁牵引变电站馈线电缆绝缘的在线监测中,效果良好。 相似文献
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针对现有高压电能计量系统存在的问题,提出了一种整体工作在高压状态实现高压电能直接计量的高压电能表解决方案。采用低压电流互感器和高压电容分压器进行信号取样的电能计量单元分别工作在A相、C相的等电位状态,电能综合单元工作在B相电位,并通过光纤进行绝缘和信息交换,所有模块的工作电源通过电容耦合直接从高压获取,使高压电能表具有体积小、强防窃电功能、明确的准确度等级、避免铁磁谐振等特点。文中介绍了高压电能表的结构、原理,并讨论了高压电能表的传感器设计、计量电路硬件设计和工作电源设计,并对其误差和样机的测试结果进行了分析。 相似文献
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针对连云港市临洪东站电气设备众多,按传统的维修模式易出现"过维修"或"欠维修"的情况,提出应根据电气设备的实际运行状况进行"状态维修".分析了电气设备绝缘系统的老化规律,提出了相应的寿命模型,指出"状态维修"的实现必须以非破坏性试验和在线检测为前提. 相似文献
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高压电气设备绝缘在线监测技术浅论 总被引:1,自引:0,他引:1
本文着重对高压电气设备绝缘在线监测技术的意义以及国内外发展现状进行阐述。简单介绍了绝缘在线监测技术的基本原理和系统组成及功能特点等,并提出了在线监测技术今后的发展方向。 相似文献
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介绍电气设备技术管理中的信息管理和技术监督管理,说明了在信息管理和技术监督管理中应进行信息数据收集、建立信息数据库,对收集的数据信息通过技术监督管理手段进行趋势分析,随时掌握设备动态的健康状况,保障电气设备安全稳定运行。 相似文献
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运行的高压电气设备中许多是电容型的,其运行的绝缘可靠性对安全至关重要。根据多年对电容型试品末电屏绝缘预防性试验工作的总结,并结合历年省内外其它单位进行电容型试品末电屏绝缘试验的结果进行对比分析.总结和判断试品是否进水受潮的经验。 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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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 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