煤矿供电线路允许压降的分析及计算

"煤矿供电线路压降不超过5%",在煤炭行业中被广泛的应用,已经成为了一个不成文的行业要求。供电线路超过5%的压降在技术上究竟是否可行?本文针对具体工程就此问题,查阅了相关的规范和手册等资料,并进行了详细的压降分析计算,同时给出了不同供电电压等级下的线路压降的最小值。     

煤矿机电设备双电源供电方式安全设计探讨

要确保煤矿开采作业安全性,保证井下机电设备得到持续、可靠的电力支持,煤矿企业的电源供电方式必须设计合理,探讨了煤矿机电设备双电源供电安全设计的原则,结合实例分析了双电源供电系统中各装置的设置情况,为同类企业双电源供系统设计提供参考,为煤矿企业安全生产提供可靠保障。     

国家安全监管总局 国家煤矿安监局 要求加强煤矿机电运输安全管理工作

国家安全监管总局、国家煤矿安监局于2008年9月26日发出《关于加强煤矿机电运输安全管理工作的通知》指出,为保障煤矿安全生产,应从以下方面加强煤矿机电运输安全管理工作：1．认真落实煤矿机电运输安全管理责任;2．切实提升煤矿供电安全保障水平;3．加强电气设备安全性能管理;4．完善提升运输设施;     

提高煤矿供电系统可靠性的措施

安全性是煤矿资源开采过程中最重要的因素之一。如今煤矿产量日益增加,切实保障供电系统的安全性是保证煤矿工作人员生命安全的根本。实践证明,提高煤矿供电系统的可靠性具有重要的意义,重点分析了煤矿供电系统可靠性的意义与现阶段问题即:供电电源设计、设备更新管理、电气保护质量以及事故应急预案,最后提出解决策略:先从安全教育培训出发,在注重设备系统的可靠性以及供电的持续性,提高煤矿供电系统的供电技术、预防电力供应中断等一系列相关应急措施对煤矿供电系统进行保障。     

浅析排土场环网供电方式及效果

不同供电网配电方式对供电可靠性不同。本文主要基于某露天煤矿疏干降水供电系统的连接方式、距离、电压过低等原因引起电力设备无法启动、运行及对设备造成的损害及解决方式,通过对供电材质、线径、距离、等各种因素进行分析利弊,解决了线路过长所造成的电压降问题,保障安全高效供电的可靠性。     

试析当前中国煤矿供电安全管理

针对中国煤矿供电的安全管理问题,分析煤电供电安全形势,阐述中国煤矿供电安全的现状和存在的问题,提出改善煤矿供电安全的建议。     

安全供电和机电设备维护管理与创新实践

安全生产无小事,确保供电安全和机电运行设备的正常维护和良好运作,是煤矿企业安全生产的重要前提。本文以山东能源枣矿集团安全供电和机电设备维护管理与创新实践为课题,就安全供电和机电设备管理现状及问题表现进行阐述,对安全供电和机电设备维护管理的创新,提出探索思路,以更好保障员工安全,保证生产经营活动顺利开展。     

煤矿井下供电设备安全现状分析与策略探讨

针对煤矿井下易爆场所及生产安全威胁的严重性,概述了煤井下供电设备的安全现状,结合设备老旧、长距离输电安全隐患,监测自动化水平低下、生产不符合行业规范等问题,提出针对性的解决方案,通过方案实施为供电设备安全运行提供保障。     

煤矿供电保护系统改造优化探究

对于煤矿企业,供电系统属于最为关键的系统,其对于煤矿开采作业会产生极为关键的影响,也是保障煤矿开采作业顺利开展的基础与保障。结合屯兰矿实际情况,分析屯兰矿供电系统运行中存在的问题,并且制定了具有针对性的应对方案,通过实践应用之后得出了,优化改造后的供电保护系统能够确保供电系统更加安全与稳定运行,从而为煤矿开采作业提供可靠保障。     

煤矿井下供电继电保护相关问题的探讨

面对供电故障发生率逐年升高、供电系统越来越复杂的形势,提高继电保护效率是保证煤矿电网正常运行的必要条件。通过分析介绍供电系统中电力设备质量及人为因素引发的故障,提出了供电继电保护系统安全、稳定运行,有效预防电力事故发生相应的措施,以期为煤矿井下安全施工提供强有力的保障。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.