Using the power cable has been over a hundred years of history. Since 1879, American inventor TA Edison copper rod wrapped with jute penetrate the iron pipe, then filled with a mixture of bitumen and other cables made in the iron pipe, creating underground transmission; the 1889 British SZ Ferran ladder with one thousand 10101010 V oil impregnated paper insulated cables between London and Deptford laying; then in 1908 the British built 20 kV cable network, since power cables are more widely used in electric power construction. Now, with the constant improvement of our national economy, cities and roads, people's growing awareness of city beautification, government planning efforts also increases. In the cities and road reconstruction and beautification, the overhead line has become a barrier to its development, and its hidden power cables and laying good performance, has become the darling of urban renewal.

The pace of reform further and further away, more and more kinds of cables, using cable technology has become increasingly mature. China's cable 10KV grid use most is the use of three-core cables, and because it is laid underground, which requires cable insulation itself and its annexes higher. Stage, cable accessories Guangdong used are: cable head end, among the first cable connector and cable T. These accessories are divided into mastic, cold shrink and shrink-type three different sizes, in this simple analysis and discussion of these three materials and the use of accessories.

A first, three sizes of cable accessories material was analyzed:

1.1, thermal cable accessories widely used in the construction of electric power, which uses heat-shrinkable cross-linked polyethylene material, which uses nuclear materials like polyethylene radiation, the polymer becomes a linear structure of the original material mesh structure, materials into memory, and then subjected to sulfonation treatment processes. That is to expand it in a heated state, cooled down by nuclear radiation, Ruoguo again heated, the material will return to its original state.

1.2, cold shrinkage cable accessories is a new use of cable accessories this year, it uses elastic materials (commonly used silicone rubber and ethylene propylene rubber, etc.) vulcanization molding, and then mechanically stretch its inner diameter to expand, and then the prefabricated spiral plastic cylinder into the tensile expansion of the inside of the accessories, support the tensile elastic accessories, Thus constitute a variety of cable accessories of various parts. When installing on site, it is only necessary to set these pre-expanded fittings at the end of the finished cable or at the joint, and then pull the helical plastic cylinders inside the fittings out of the end of the fittings, as these fittings are made of elastic materials, after pulling out the helical plastic cylinders for support, The cable fittings automatically tighten the cable accessories that are formed on the cable insulation.

1.3, pouring cable accessories is the use of a corresponding mold to fix the need for construction of the cable parts, into the mold pouring epoxy resin and other insulating materials, until these insulating materials dry and remove the mold on the line pull. This kind of cable accessory installation process is relatively simple, but the weather and other natural and geographical environment requirements are high, can not be poured in wet weather or place, it is not appropriate to pour in the dusty site, so as not to reduce the cable accessories damp, contaminated and lower cable insulation. Because the weather in the south is relatively humid, coupled with the construction site is inevitably dusty, the installation quality of pouring cable accessories has a greater impact, so the use of such accessories in Guangdong is less. The pouring cable accessories are no longer analyzed in detail here.

Second, secondly, in the installation of the process of heat shrinkage and cold shrinkage cable accessories have their own characteristics and advantages and disadvantages:

2.1, heat shrinkage Cable accessories Installation: First will need to install accessories of the cable terminal stripping, and according to the cable accessories installation requirements for processing, and then with heat shrinkage materials made of the main insulation casing cover cable, the use of heat shrinkage principle of the casing heating, so that the main insulation casing tightly shrinkage in the cable semiconductor tube, and then package metal shielding layer, Finally, the external casing is thermally shrunk. Component heating shrinkage is the key link in the quality of hot shrink, it is best to put the cable on before heating, which is conducive to heating operation and uniform shrinkage of components. When heating, be aware of:

① Heating shrinkage temperature is Ll0℃ 120 ℃.

② Adjustable Spray lamp flame is yellow soft flame, beware of high temperature blue flame.

Disadvantages: The construction process is more complex. Installation heating requires the use of a hairdryer or open fire heating, which requires a temporary power supply or open fire heating device in the construction site. If the installation of temporary power supply, may be a lot of human and material resources, so the thermal shrinkage cable accessories installed generally using natural gas spray gun heating. The use of open fire heating requires high safety measures. In the use of natural gas for outdoor heating, there are many fire safety problems, to the construction of the project brought fire and other safety risks, it is necessary to increase a variety of fire safety measures to prevent, which increases the construction difficulties and construction costs.

2.2, cold shrinkage Cable Accessories installation: First according to the requirements of the attachment installation of the cable peel off and clean up, and then in order to the cable attachment into the corresponding cable area, from the inside out of the support of the spiral plastic cylinder, so that the cable accessories using their own material elastic tight pressure attached to the cable, Thus to the attachment installation site of the cable to play an insulating and protective effect, to achieve the installation of the attachment effect and requirements. The cold shrinkage method eliminates the hassle and unsafe factors that heat shrinkage products need to heat, makes the operation of the accessory installation relatively simple, and the cold shrinkage material is easy to use and quick to install, greatly reduces the time of construction preparation and safety measures implementation, and saves valuable time for power outage tasks and repair work to complete cable installation and access within a limited power outage time.

At the same time cold shrinkage cable accessories installation is not affected by the geographical environment and natural and social environment, suitable for a wide range of cable engineering use. The disadvantage is that the cold shrinkage cable accessories on the storage conditions require a higher heat shrinkage, generally required to be used in the factory half a year, the physical and chemical properties of the accessory material relative to the heat shrinkage accessories to be lower, in the high temperature and dry environment storage easy aging and elasticity weakened.

It must be pointed out that before installing to the cable, the cold shrinkage cable attachment is in a high tension state, so it is necessary to ensure that during the storage period, the cold shrinkage parts should not have obvious permanent deformation or elastic stress relaxation, otherwise installed on the cable can not be guaranteed to have sufficient elastic compression force, so that good interface characteristics can not be guaranteed.

Third, from the operation of the Economic and security analysis:

1) Cold shrinkage cable accessories raw materials and production costs are high, so the market price of cold shrinkage cable accessories to heat shrinkage cable accessories a lot higher. In terms of service life, cold and hot shrinkage cable accessories are the same as the cable, so in terms of economy thermal shrinkage cable accessories are superior to cold shrinkage cable accessories.

2) Cold Shrinkage cable accessories have a good elasticity, its strong resilience is the attachment has enough grip force, no matter how the ambient temperature changes, accessories can be guaranteed to firmly hold the holding area. This ensures that the water and moisture are not inhaled, thus ensuring a safe internal crawl distance of the cable. The shrinkage temperature of the heat shrinkable cable accessory is 100~140℃, that is, when the heating is installed to meet the shrinkage conditions of the attachment, if the ambient temperature is reduced, due to the different expansion coefficient of the cable and heat shrinkage material and the formation of a gap between the attachment and the cable, then the water and moisture and other substances through the respiration of the cable into the gap , which destroys the insulation of the cable and endangers the safe operation of the cable.

To sum up, thermal shrinkage cable Accessories Although the installation process is complex, but because of its cheap, in Guangdong and other places with little temperature difference is still widely used, and cold shrinkage type of cable accessories because of its simple construction technology and good operation performance, in the power system is also more and more widely used, but its storage period and material performance need to be improved, Production costs need to be reduced.

For more information, please contact to

contact：15918777767

              020-82586869

  QQ:      281494549

E-mail： lily@gzhelectric.com

10kV冷缩、热缩电缆附件的安装及选用

电力电缆的使用至今已有百余年历史。自1879年美国发明家T.A.爱迪生将铜棒用黄麻包绕后穿入铁管内，然后在铁管内填充沥青等混合物制成电缆，开创了地下输电；到1889年英国人S.Z.费兰梯用10101010千伏油浸纸绝缘电缆在伦敦与德特福德之间敷设；再到1908年英国建成20千伏电缆网，自此电力电缆在电力建设中得到越来越广泛的应用。而今，随着我国经济的发展，城市及道路的不断完善，人们对城市美化的意识不断增强，政府规划力度也随之增强。在城市及道路改造及美化中，架空线路俨然成为了阻碍其发展的障碍，而电力电缆因其敷设的隐蔽性及良好的性能，成为了城市改造的宠儿。

改造的脚步越走越远，电缆的种类越来越多，电缆的使用技术也越来越成熟。我国10KV电网使用的电缆大多数是采用三芯电缆，且因其是埋地敷设，这就对电缆本身及其附件的绝缘要求较高。现阶段，广东地区所使用的电缆附件主要有：电缆终端头、电缆中间头及电缆T接头。这些附件又分为浇注式、冷缩式和热缩式三种不同规格，在此对这三种附件材质及使用进行简单的分析讨论。

一、首先，对三种规格的电缆附件的材质进行分析：

1.1、热缩电缆附件在电力施工中较为广泛使用，它采用交联聚乙烯等热缩材料，它利用核子对聚乙烯等材料进行辐射，使原来线性结构的高分子材料变为网状结构的，变成有记忆功能的材料，再经过磺化处理等工序。就是说在加热状态下使其膨胀，通过核辐射后冷却下来，若果再次加热，材料会回到原来的状态。

1.2、冷缩电缆附件是一种今年来新兴使用的电缆附件，它利用带弹性的材料(常用硅橡胶和乙丙橡胶等)硫化成型，再用机械将其内径拉伸扩大，然后将预制好的螺旋型塑料圆柱放入拉伸扩大后的配件内部，支撑起拉伸后的弹性配件，从而构成各种电缆配件的各个零部件。现场安装的时候，只需要将这些预先扩张好的配件套在处理好后的电缆末端或接头处，然后将配件里面的螺旋型的塑料圆柱从配件的里端抽出，因这些配件是带弹性的材料制成，抽出支撑用的螺旋型的塑料圆柱后，电缆配件就会自动压紧在电缆绝缘上而构成的电缆附件。

1.3、浇注式电缆附件是利用一个相应的模具固定需施工的电缆部位后，往里模具内浇注环氧树脂等绝缘材料，待这些绝缘材料干燥后拆下模具就行拉。该种电缆附件安装工序比较简单，但对天气等自然和地理环境要求较高，不能在潮湿的天气或地方浇注，也不宜在尘土飞扬的场地浇注，以免电缆附件受潮降、受污而降低电缆绝缘。由于南方天气比较潮湿，再加上施工工地难免灰尘弥漫，对浇注式电缆附件的安装质量影响较大，故在广东地区较少使用这种附件。在此不再对浇注式电缆附件作详细分析。

二、其次，在安装的工序上热缩及冷缩电缆附件各有其特点及优劣：

2.1、热缩电缆附件的安装：首先将需要安装附件的电缆终端剥开，并按电缆附件安装要求进行处理，然后用热缩材料制作的主绝缘套管套住电缆，利用热缩原理对套管进行加热，使主绝缘套管紧密地外缩在电缆半导体管，再包金属屏蔽层，最后对外护套管进行热缩。部件加热收缩是热缩头制作质量的关键环节，加热前最好将电缆立放，有利于加热操作和部件均匀收缩。加热时应注意：

①加热收缩温度为ll0℃一120℃。

②调节喷灯火焰呈黄色柔和火焰，谨防高温蓝色火焰。

缺点：施工的工序较为复杂。安装加热需要用到电吹风或明火加热，这就要求施工场所有临时电源或明火加热装置。若安装临时电源，可能将耗费大量的人力物力，故进行热缩型电缆附件安装时一般使用天然气喷枪加热。使用明火加热对安全措施的要求较高。在使用天然气进行户外加热时，产生了许多消防安全问题，给工程施工带来了火灾等安全隐患，需增加各种消防安全措施加以防范，这就增加了施工的难点和施工成本。

2.2、冷缩电缆附件的安装：首先按附件安装的要求将电缆剥开并进行清理，然后按顺序将电缆附件套入相应的电缆部位，从内向外抽出支撑用的螺旋型的塑料圆柱，使电缆附件利用自身材料的弹力紧密压附在电缆上，从而对附件安装部位的电缆起到绝缘和保护作用，达到附件安装的效果和要求。冷缩法省去了热缩产品需加热的麻烦和不安全因素，使附件安装的工序变得相对简单，且冷缩材料使用方便、安装快捷，大大减少了施工准备和安全措施实施的时间，为在有限的停电时间内完成电缆安装接入的停电任务及抢修工作节约了宝贵的时间。

同时冷缩电缆附件安装不受地理环境和自然、社会环境的影响，适合在各种电缆工程中广泛使用。缺点是冷缩电缆附件对储存条件要求比热缩的要高，一般要求在出厂半年内使用，附件材质的物理和化学性能相对热缩附件的要低，在高温干燥的环境中存放容易老化和弹性变弱。

必须指出的是，在安装到电缆上之前，冷收缩式电缆附件是处于高张力状态下，因此必须保证在贮存期内，冷收缩式部件不应有明显的永久变形或弹性应力松弛，否则安装在电缆上以后不能保证有足够的弹性压紧力，从而不能保证良好的界面特性。

三、从运行的经济性和安全性分析：

1）冷缩电缆附件原材料及生产成本高，故而冷缩电缆附件的市场价格要比热缩电缆附件的高出许多。从使用寿命来看冷、热缩电缆附件均与电缆同寿，故而在经济性方面热缩电缆附件优胜于冷缩电缆附件。

2）冷缩电缆附件具有良好的弹性，其强大的回弹性能是附件有足够的抱紧力，无论环境温度如何变化，附件都能保证牢牢地抱紧被抱部位。这样就能保证水和潮气不被吸入，从而很好的保证了电缆安全的内爬电距离。而热缩电缆附件的收缩温度在100~140℃，也即是在安装加热时才能满足附件的收缩条件，如果环境温度降低时，由于电缆和热缩材料的膨胀系数不同而产生脱层，在附件与电缆之间形成缝隙，这时水和潮气等物质通过电缆的呼吸作用进入缝隙，破坏电缆的绝缘，危害电缆的安全运行。

综上所述，热缩电缆附件虽然安装工序复杂，但因其价格便宜，在广东等地温差不大的地区仍然广泛使用；而冷缩型的电缆附件因为其简单的施工工艺及良好运行的性能，在电力系统中也被越来越广泛的使用，但其存储期限和材料性能有待提高，生产成本有待降低。

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