10kV架空绝缘导线雷击断线分析及对策

通过分析一起架空绝缘导线雷击断线的事故原因,提出适合10kV配电线路架空绝缘导线雷击断线的防范措施。并对措施进行分析,找出最适合的方法,选定采用金属氧化物避雷器等防雷措施,可有效地防止架空绝缘导线雷击断线事故。     

配网线路差异化雷害风险评估技术

10kV配电线路由于绝缘水平比较低,雷击闪络更容易发生,易导致因此而生成的工频电弧将导线烧断。伴随电力系统配电线路绝缘化的改造,雷击断线问题更加突出。而近年来,国内外架空绝缘导线发生雷击断线和裸导线闪络跳闸的事件十分频繁,造成了多起人身伤亡事故和巨大的经济损失。配网架空线路雷击跳闸率高,极端条件下存在雷击断线问题。该文通过分析10k V配网架空线路雷击跳闸和雷击断线的机理,以及目前配网架空线路防雷现状,提出配网架空线路差异化雷害风险评估技术,并通过实际生产运用证明其行之有效。     

配电系统的防雷与接地

本文分析10kV配网防雷中的线路运行的防雷和10kV变压器的防雷。目前10kV线路的防雷主要依靠10kV氧化锌避雷器来实现，本文阐述了在重雷区10kV避雷器的安装有效距离。本文分析了10kV架空绝缘线路、电缆线路长期运行情况带来的雷电破坏情况及解决方法。针对10kV架空线路与电缆线路混合使用情况日益增加的情况，本文分析了由于架空线路和电缆线路两种不同波阻抗形成电波叠加，造成电缆线路的破坏。10kV配电变压器避雷器与中性点同一地点接地时，由于接地电阻在大雷电流作用下形成的中性点电位升高，从而引起10kV配电变压器的损坏，并提出解决方法。     

对10kV架空绝缘配电线路防雷措施的探讨

对于防止架空绝缘导线雷击断线的措施是多种多样的,各有优缺点,本文分析了绝缘导线雷击断线原因,对10kV架空绝缘配电线路防雷措施进行了探讨,提出了自己的几点想法,仅供同行参考学习。     

10kV配电线路防雷措施研究

雷击对配电线路的安全运行带来较大的威胁．目前10kV架空配电线路上已广泛使用了绝缘导线,但使用过程中出现了新的问题。针对10kV架空配电线路常发生雷击断线事故的现象,研究了雷击断线及跳闸的机理,并提出了雷击灭弧及防雷的具体措施,并结合某经济开发区所属供电公司实例说明防雷改造工程对保护配电线及提高供电可靠性的实际效果。     

农网10kV配电线路单相接地故障分析及处理

介绍了农网10kV配电线路经常发生单相接地故障的原因主要是导线断线、绝缘子击穿和导线与树木短接等几种.故障后还易造成谐振过电压现象.应采取加强巡视和定期设备试验等预防措施;并建议采用小电流接地自动选线装置、单相接地故障检测系统及防爆自动脱离型过电压保护器等新技术新设备,发生故障后,采用"排除法"快速处理及线路整体绝缘摇测法等方法,确保变配电设备安全运行.     

基于绝缘导线雷击断线机理的防雷装置研究与应用

10 kV架空裸导线路绝缘水平低,很容易遭受雷击引起绝缘子闪络断线事故。该文通过收集10kV架空线路的跳闸数据,现场勘察地形地貌特征,选择典型的地点进行直击雷防护措施研究。通过软件仿真计算,将各种防护装置模型嵌入到选择的线路中,提出最优的直击雷防护措施。采用一种不接地、而且老化后不影响线路安全运行、能合理的配合计数器的一种防雷装置来实施。     

探讨架空绝缘线路的防雷击断线措施

文章结合对架空绝缘导线雷击断线的机理的分析,阐述了防止雷击断线的技术措施,并提出了安装线路过电压保护器是防止配电线路架空绝缘导线雷击断线的有效方法。     

10kV系统接地故障原因查找与分析

随着我国逐步实施了电网工程改造,传统的"两线接地"的供电方式逐步被中性点不接地"三相三线"所替代。本文首先介绍了10kV配电线路接地故障的查找方法,然后论述了10kV系统接地故障的有效防范措施。     

配电线路防雷措施简介

雷电对电力设备有很大的危害性,配电网防雷的目的是使线路的雷害跳闸次数减少到最低限度,配电线路设备损害几率最小,本文对如何防止配电线路及其相关设备遭受雷电袭击进行了分析。其中,重点分析了10kV架空绝缘导线雷击断线的防护措施。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-