我国首次以燃料电池为动力的飞艇试飞成功

中铝华中铜业（原大冶铜板带）公司生产的用于3G通讯的6km超长高精度射频电缆无氧铜带日前正式出厂,标志着其3G通讯电缆无氧铜带不仅在质量、产量上居全国领先位置,且在长度上也创造了行业记录。     

浅谈煤矿通讯网络中光缆替换电缆的必要性

随着通讯技术的高速发展及网络用户对带宽要求的不断提高,电缆在大部分网络中及主干路由上,已经成为通讯业务发展的瓶颈,电缆过去的优点已经逐渐地被现在的缺点所掩盖,光进铜退的时代来了。它将逐渐被具有重量轻、体积小、传输距离远、信号衰减少、抗电磁干扰以及成本较低等优点的光缆所替代。光纤的海量传输带宽和较低的成本等诸多优越性,使得电缆在施工应用中的性价比逐渐下降,所以采用光缆替换电缆是未来通讯传输发展的必然趋势。     

基于虚拟样机和粒子系统仿真技术的虚拟布线方法

将虚拟样机技术应用于机电产品电缆布线问题,提出了虚拟布线方法。该方法首先根据设计方案建立产品虚拟样机、电缆连接列表、电缆接口、电缆材料、截面参数等信息,基于上述信息以及电缆布线规范,利用虚拟样机技术对可视化和人机交互能力的支持规划出卡箍位置和电缆路径,进而计算电缆长度,在此基础上利用粒子系统仿真技术计算电缆形状,据此生成相应的电缆模型。在探讨了机电产品电缆布线问题及其求解思路的基础上,着重研究了机电产品的信息模型及虚拟布线的关键技术。通过一个实例证明了该方法的可行性。     

新型电缆材料一预制分支电缆

介绍了预制分支电缆的优点，并通过与普通电缆、封闭式母线的技术经济指标对比分析，指出了该材料的广泛用途。     

浅谈无卤低烟阻燃电缆性能与挤出工艺

无卤是通过对电缆所有被覆材料燃烧时腐蚀性气体的含量进行评定。低烟是通过电缆燃烧时测定的最小透光率来评定,与电缆用阻燃材料及电缆结构密切相关。而电缆的阻燃性能不仅与电缆结构有关,还与材料氧指数、阻燃机理有关。无卤阻燃电缆结构变化较多,不同使用场所、不同阻燃等级均不同。无卤低烟阻燃电缆是阻燃电缆的升级产品。本文对无卤低烟阻燃电缆的性能与挤出工艺进行探讨。     

B类阻燃电缆结构与生产工艺浅析

近来,由于电缆火灾的教训,高分子材料的阻燃技术也应运而生,采用高分子阻燃材料的阻燃电缆技术取得了巨大发展,二十世纪八十年代后期阻燃电缆已成为电缆发展的必然趋势。阻燃型电力电缆按其阻燃的效果不同,可分为三个等级:A级阻燃,B级阻燃,C级阻燃。     

电力电缆接头温度场分布探究分析

在实际的电力传输过程中,长距离的电缆线每100米左右就有一个接头,由于电缆接头众多,并且容易发生内部故障和外部故障,引发的电缆火灾在整个电缆事故中约占一半以上。如果电缆元件的热容量小,测点与接头间应注入高绝缘导热好的材料,电缆与环境间则使用绝热材料。当用电设备正常运行时,接头处的电阻会随着电缆内外温差的增大而增大,也就是说可以将电缆的温度作为接头故障的预警信号。     

溶液法MDPE 51-35B电缆护套料开发

介绍了溶液法工艺生产中密度聚乙烯护套料的方法 ,技术性能 ,应用性能 ,工艺参数和加工性能。表明了该护套料是一种新型适用于通讯电缆护套品种。     

铝合金电缆使用之我见

在铜资源严重缺乏的情况下，电缆行业“以铝代铜”无异于一场材料革命。在欧美等发达地区，性价比更高、电气性能优越的铝合金电缆已被成功应用了40多年，国内的一些新建工程也开始尝试使用铝合金电缆。本文对铝芯电缆、铜电缆和铝合金电缆的性能进行了分析，并具体阐述了铝合金电缆在住宅配电系统中的适应性，指出了选用铝台金电缆需要注意的问题，客观地看待铝合金电缆的使用问题。     

电缆中间接头用石墨基柔性材料防火防爆性能研究

受自身质量和外部因素影响,电缆短路事件频繁发生,对此,研究电缆中间接头用石墨基柔性材料的防火防爆性能十分必要。选择实验仪器、石墨基柔性材料、普通树脂基复合材料和添加7%红磷成碳剂的树脂基复合材料,结合柔性综合防护装置技术参数,建立材料性能测试方法。通过提取材料结构表征,研究石墨基柔性材料对电缆释放性能的影响,燃烧时间对材料防火性能的影响,以及不同负荷对材料防爆性能的影响。结果表明:石墨基柔性材料能够约束电缆的热释放和有害气体释放,在短时间内的防火测试中,材料残碳率比其他两组对照材料高了7.03%和20.86%;该材料能够将电缆载流量约束在合理范围内,保证供电的同时,延缓爆炸发生,可见该材料有更好的防火防爆性能。     

核电站电缆料的研究进展

依据核电站电缆的种类,介绍了核电站电缆料的种类、性能、生产工艺和国内外的研究现状。研究发现,制备核电站电缆绝缘料主要用交联聚乙烯(XLPE)和硅橡胶(或硅橡胶复合材料),此两种原料具有优良的耐热性、电绝缘性、耐低温性、耐化学性和良好的耐辐射性;核电站电缆料应具有低烟无卤、耐阻燃性和耐环境性能;其制备方法主要是挤出法,此方法生产工艺简单、成本低。最后展望了核电站电缆料的发展趋势。     

对GB 15579.11-1998《弧焊设备安全要求第11部分:电焊钳》标准修订的建议

根据多年来企业反映和实际检测工作中遇到的问题,文章从绝缘电阻、温升值、温升测试方法、绝缘材料耐热、耐焊接飞溅物、焊接电缆的连接6个方面对GB 15579.11-1998《弧焊设备安全要求第11部分:电焊钳》标准修订提出想法和建议。     

Thermal and electrical assessment of flexible

The electrical and thermal is described of a flexible liquid nitrogen cooled, cryoresistive cable with plastic tape insulation. The tape materials considered are low-loss polypropylene paper laminate (LLPP/P), polyethylene, melinex, and polypropylene. The effects of the variation of conductor size, circuit length, liquid nitrogen pressure and temperature, thermal resistivity of the insulation and coolant-flow arrangements, on the cable ratings are investigated. For lengths of 10 km between pumping and refrigeration stations at 138 kV the capability for all the tape materials is seen to be 1 GVA and at 500 kV in the order of 3 GVA. At 1200 kV, LLPP/paper appears to be the only material suitable.     

Self-healing of mechanical damage of polyethylene/microcapsules electrical insulation composite material

Polyethylene (PE) cable has become an important carrier of the modern power grid due to its excellent electrical insulation performance. However, small damages can inevitably occur during the preparation and operation of the materials, which can distort electric field and trigger discharge, seriously threatening power supply safety. The self-healing of insulation materials by doping microcapsules is a new research innovation. In this paper, the self-healing PE/microcapsules insulation composite material was prepared, and the self-healing behavior of mechanical damage was emphatically analyzed by scratch damage test and crack propagation simulation. The results show that the composite material with 1 wt% microcapsule has better insulation strength. Moreover, the composite material can fill the defective structures, restore local electrical properties, and reverse the deterioration process of the material. The properties of PE/microcapsules composite material are mainly related to the characteristics of the microcapsule itself and the interface introduced by the microcapsules. The properties of the repaired product can directly affect the recovery degree of the damaged area. The stress action during damage can smoothly trigger its self-healing behavior. In conclusion, the PE composite material doped with 1 wt% microcapsules can achieve a good self-healing effect on mechanical damage.

     

Electrical properties of flexible polypropylene based cable insulation materials

DC resistivity and AC breakdown strength of flexible polypropylene (trade marked name Hifax) cable insulation materials have been measured at selected temperatures. The AC breakdown data has been analysed in terms of Weibull distribution. The results show that Hifax cable insulation has a higher AC breakdown strength than EPR (ethylene propylene rubber) and XLPE (crosslinked polyethylene), both of which are widely used for DC cable insulation. It is concluded that blending Hifax with ordinary polypropylene decreases the breakdown strength. The DC resistivity of Hifax is larger than that of XLPE and oil-impregnated paper insulations. It has been found that the electrical stress coefficient of resistivity of Hifax cable insulation increases with temperature, which may have important engineering implications. An anomalous drop in resistivity has been observed for Hifax at high electrical fields, suggesting charge trapping and detrapping processes are present in these cable insulations.     

A study of breakdown strength of liquid nitrogen cooled power cables

A 66 KV liquid nitrogen cooled cryogenic cable was manufactured and tested using ac and impulse voltages.Liquid nitrogen cooled cryogenic cables will be in practical use over the 275–500 kV range. Study of the 66 kV class cable is the first step towards the development. The insulation system of this cable is polyethylene paper tape wrapped insulation impregnated with liquid nitrogen and its insulation thickness is about 7.75 mm. The influence of bending, conductor surface effect, and thickness dependence on the breakdown strength are discussed.     

An investigation of the potential of polypropylene and its blends for use in recyclable high voltage cable insulation systems

Most modern extruded high voltage cables employ cross-linked polyethylene (XLPE) as the insulation material. XLPE has excellent thermo-mechanical properties, is relatively cheap and has a low dielectric loss, which make it an ideal material for this application. Unfortunately, XLPE is not easily recycled at the end of its lifetime leading to questions concerning its long-term sustainability. A previous investigation in this series considered the potential of a range of ethylene-based systems to provide suitable recyclable alternatives to XLPE. Whilst blending could allow systems having similar thermo-mechanical and electrical properties to XLPE to be designed, it was not possible to obtain better performance than XLPE using these systems. Polypropylene offers, potentially, a route to improved insulation systems by virtue of its higher melting point and excellent dielectric properties. However, traditional isotactic polypropylenes have always had the problem of being too brittle for inclusion into practical cable designs. Recently a broad range of propylene co-polymers having improved ductility have become available, which may prove more suitable. The current study compares traditional isotactic and syndiotactic polypropylenes to a range of commercially available propylene co-polymers and focuses on their morphology, thermal, thermo-mechanical and electrical properties. These parameters were then taken together to identify the most suitable candidate materials for future cable applications. The use of blending as a means to further optimise the various material properties was also explored.     

Testing of the fire-proof functionality of cable insulation under fire conditions via insulation resistance measurements

Two different designs for low-fire-hazard cables were tested under conditions similar to those of the fire test specified in IEC 60331-21. In addition to the other standard requirements, an insulation resistance meter was connected directly to the measurement circuit to monitor the actual state of the cable insulation during the fire tests. The suitability of this measurement of the insulation resistance was demonstrated by testing cables with fire barriers made from mica glass tape and from ceramifiable silicone rubber. The results showed that insulation resistance is sensitively affected by the melting of the organic components of insulation, by the decomposition of the fire retardant, by the ignition of the core insulation and by the formation of a silica layer during a fire test. The results also helped to reveal the importance of flame conductivity in performing such tests. The initial observations are supported by thermogravimetry and differential scanning calorimetry, which are beneficial as a first step towards understanding the mechanisms of fire-proof functionality in cables. The suggested procedure can assist in the comparison of the fire-proof functionalities of different cable designs, in the analysis of their failure mechanisms and in cable design optimisation.     

纳米TiO2/液体硅橡胶直流电缆附件绝缘复合材料的介电性能

高压直流电缆附件在电力系统运行中,由于复合绝缘电导率不匹配极易导致电场畸变引发绝缘故障。针对这一问题,采用直接共混法制备了不同掺杂浓度的纳米TiO₂/液体硅橡胶（LSR）复合材料,并对其微观形貌和介电性能进行了测试研究。结果表明:纳米TiO₂粒子在LSR基体中分散较均匀,随着TiO₂掺杂含量的增加,纳米TiO₂/LSR复合材料试样的相对介电常数和介质损耗因数增大。当纳米TiO₂粒子添加量为4wt%时,纳米TiO₂/LSR复合材料的电导率与电缆主绝缘交联聚乙烯（XLPE）的电导率近似相等,且随着电场强度的增大,两者的电导率变化趋势也基本一致。电声脉冲法（PEA）测量结果表明,添加4wt% TiO₂的纳米TiO₂/LSR复合材料内积聚的空间电荷最少。纳米TiO₂粒子的掺杂,提高了TiO₂/LSR复合材料电缆附件绝缘电导率对电场强度的响应依赖特性,使其能与XLPE绝缘电导率较好地匹配,同时一定程度地抑制了空间电荷的积累,有助于直流电缆附件内复合绝缘电场的均匀分布。      

决策树技术在电缆绝缘状态评估中的应用

电缆的绝缘状态通常可以分为良好、不好、差和故障等几种,以电缆的日常检修数据、试验数据和在线监测数据为基础,对电缆的状态进行判断是一个非常有意义的课题。采用决策树分类技术来对电缆的绝缘状态进行分类,分别对各种类型数据形成子树,然后通过子树合成技术形成最终的决策树,从而对电缆的绝缘状态进行判断。通过一个实际电缆的各种数据,采用SPSS软件进行实际应用,最终的仿真结果说明决策树技术是一种非常有效的电缆绝缘状态分类技术。