提高10kV配电网供电可靠性的对策

<正>1 10 k V配电网的特点(1)10 k V配电网一般都具有网架结构较薄弱、供电线路长、T接点多、分布范围广等特点。特别是农网线路,线路结构基本上是单电源树干式,而且线路分段断路器安装少,一旦线路某处发生故障,就很可能引起整条线路停电。(2)农村配电网整体运维管理水平较低,用电季节性强,用电谷期设备利用率低。(3)县供电企业在配电网自动化技术应用方面水平较低,故障处理技术水平低,机动能力不强。10 k V配电网的这些特点在很大程度上影响其供     

10kV电缆故障分析及防范措施

正在电力系统中,电力电缆故障是常见的问题之一,而10 k V配电网与城市居民的日常生活也是息息相关,它的施工质量与运行安全直接对国内的供电安全、电力企业建设、电力企业稳定以及经济与社会双重效益带来直接的影响。对于10 k V电缆,应该做好故障的排查,一旦发现故障,应该及时做好检修,将故障与隐患排除,下面就两起10 k V电缆故障进行分析并提出事故反措。1 110 k V后海变电站10 k V城邦线F15电缆故障     

10kV配电网的电能计量及线损管理研究

本文首先阐述10k V配电网的电能计量装置,然后具体解析10k V配电网线损管理优化措施,旨在为提升10k V配电网运行质量提供一定参考。     

10kV金属封闭铠装式开关柜内部发热分析

正近几年随着我国配电网建设突飞猛进,在配电网中,变电站、配电室多采用室内金属封闭铠装式开关柜(如KYN28-12型),变电站或配电室的10 k V高压开关柜的故障往往会危及10 k V母线,危及人身、电网和设备安全。经对大量现场数据分析,10 k V开关柜内部故障并不是突发性的,往往伴随着设备发热。金属封闭铠装式开关柜整体是由柜体和中置式可     

减少配电变压器接线柱更换时间

1选题理由随着生活水平的提高,人们对电的依赖性也越来越强,同时对供电的可靠性要求也越来越高。减少电网故障抢修时间也成为提高供电可靠性的一种手段。10 k V配电网设备点多面广,分布遍及城乡各地,设备多,管理困难,发生故障几率较高。配电设备中配电变压器是最重要的组成部分,其接线柱因各种原因发热烧坏现象屡见不鲜,如     

电压互感器高压熔断器频繁熔断的原因

正近几年来,德庆电网各变电站频繁发生10 k V电压互感器高压保险管烧断故障,给设备运行维护带来了极大的困扰,一般情况下发生这类故障的设备原因主要有以下几种。1电压互感器高压熔断器频繁熔断的问题分析当10 k V的出线受到直击雷或感应雷、变电站的地网接地电阻偏高时,雷电流不能及时有效地引入大地,这时就会发生10 k V电压互感器高压保险管烧断的现象,于是组织试验人员对德庆电网的12座变电站进行了测试,测     

10kV配电网单相接地故障及处理措施

由于我国电力事业的改革与发展,使得10k V的配电网出现了明显的变化,尤其是在供电方面,降低了故障出现的几率。在实际的运行过程中可能会出现许多故障问题,其中一种是单相接地故障。文章主要研究在10k V配电网的运行过程中出现的单相接地故障以及处理的措施,希望对以后的研究起到一定的帮助。     

10kV系统中性点接地补偿装置及其主要设备的选择

我国 10 k V系统大多数都采用中性点不接地系统。随着 10 k V系统规模的扩大和电缆应用的普及 ,单相接地电容电流逐渐增大。根据实际运行经验 ,单相接地是电网的主要故障形式。 10 k V系统单相接地电容电流大于 10 A时 ,电弧便有可能不会自行熄灭 ,并极易发展为相间短路故障 ,当单相接地为间歇性弧光接地时 ,会引起幅值很高的弧光过电压 ,很容易击穿系统内绝缘较薄弱的设备 ,引发严重的事故。新部颁标准 ( DL /T6 2 0 1997)规定 :10 k V系统 (含架空线路 )单相接地故障电流大于 10 A而又需要在接地故障条件下运行时应采用消弧线圈接地方…     

10kV配网故障的形成因素与防范措施

<正>近年来,农村配网经过大规模的建设改造,网架结构较之以往有了明显的改观,但因10 k V架空线路具有结线方式复杂、运行环境特殊、维管难度较大等特点,加之长期处于露天运行,尤其在雷、雨、雪和大风等恶劣天气时,线路故障率居高不下,严重影响到当地经济发展和人民群众的生活生产秩序。10 k V配网故障原因分析配网设备自身因素。一般情况是因线路长、分支多、旧线路未改造,     

准确判断故障 减少停电时间

在现有电力生产技术条件下 ,如何减少故障停电时间 ,如何快速查找故障点 ,缩小故障范围 ,一直是我们供电企业研究探讨的课题。我们尝试从总结分析农村 1 0 k V电网故障时的电压、功率变化情况入手 ,准确地进行了农村电网的接地等故障性质判断 ,减少了故障停电时间 ,收到了较好的效果。1　农村电网现状及电网电流特性( 1 )　农村电网现状 :1 1 0 k V电网是农村供电的主要电网 ,一个 35k V变电所都要有多路 1 0 k V线路向外供电 ,线路长、供电面积大 ,一条线路最长达百公里 ,并采用中性点不接地方式。2 1 0 k V电网分散在交通不便的山区地带…     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。