Installation steps for cable intermediate connectors

1, the pretreatment of the cable

2, conductor connection

Peel the wire do not damage the wire, the joint staggered to prevent short circuit, with hydraulic clamp pressure good.

3, internal semi-conductive layer recovery

4, Insulation layer recovery

Organic silicone + self-adhesive Waterproof Tape-"Heat shrinkable tube-" insulation tape (can enhance insulation treatment).

5, recovery of the outer semi-conductive layer

6. Recovery of metal shielding layer

7, restoration of the armored layer

8, recovery of the protective sleeve

Waterproof treatment steps for low voltage wire and cable silicone wire intermediate joint

1) After the terminal is pressed, wrap the waterproof filling glue around the terminal. Shrink the heat shrinkable tube.

2) If it is generally slightly moist environment, at both ends of the cable winding on the waterproof filler tape, shrinkage casing (the two ends of the casing must be glued) can be.

3) If the environment is relatively bad, you must use self-adhesive waterproof tape to enhance waterproof (can also use hot shrinkage waterproof tape, we generally use self-adhesive tape, heat shrinkable tape is used for cable breakage repair). The method is: A, after filling the waterproof filler glue, in the filling glue outer layer with self-adhesive waterproof tape winding a layer or stretching self-adhesive waterproof tape Winding multi-layer, but the thickness is not too thick, so as not too large to cause insulation pipe cover not to go in. B, shrink the heat shrinkable tube sleeve at the glue. C, wrap the waterproof tape at both ends of the heat shrinkable tube, then wrap a layer of self-adhesive waterproof tape, wrap the waterproof tape and self-adhesive tape at both ends of the cable insulating sheath, and then heat the casing to shrink to complete.

The intermediate joint usually refers to the cable connector, that is, the cable joint in the middle of the cable line. The intermediate joint is a cable accessory for the intermediate connection of a cross-linked cable or oil-immersed cable for various voltage grades. The main function is to make the line smooth, keep the cable sealed, and ensure the insulation level at the cable joint, so that it runs safely and reliably.

Manufacture of intermediate connectors.

1. If you can buy a good quality heat shrinkable tube locally, you can put the heat shrinkable pipe on a certain cable first. Note: the diameter of the heat shrinkable tube is at least 1.5 times times the diameter of the original cable

2. Dig the cable well (manhole) where the cable is ready to connect, facilitate construction and maintenance, check whether the cable head is damp before the connector, and cut off the damp part.

3, two cables are laid in place, and the cables at the joints are placed straight and overlapping in order to cut off the end part. (because the conductor of the fracture may not be round, can not wear into the takeover)

4. Mark (center) at the position where the connector is prepared, and cut off the excess cable at the 3-5cm before this mark. (Because each phase is twisted and together, the length after separation will be different, to be finally positioned as needed)

5, according to the need for joints, from the cable fracture began to peel off the outer sheath, armored layer. Note: Do not break the insulation when peeling the armored layer.

6, the each phase is separated, peeled off the insulating layer, the stripping length is: Take over the length of the/2+3~5mm. Note: Do not hurt the conductor when peeling insulation.

7. Clean the conductor; press and connect. The number of crimping, crimping order and spacing refer to the GB14315 of the rules.

8, wipe away the excess antioxidants.

9, the use of 3M insulation tape (23#) to restore the insulation layer, tape thickness of the original insulation thickness of twice times. Note: The tape usage method is followed by instructions and wraps back and forth.

10, cover the insulating belt with PVC tape, wrap a back and forth.

11. Restore the electrical connection of the armored layer. If there is a 3M armor belt, the armor strap can be used. It is recommended to use tin-plated copper braided wire crossover, both ends with copper filament gang. If there is a condition for solder.

12,A, if there is a heat shrinkable tube, pull the heat shrinkable pipe to the joint, heat shrinkage, the two ends of the mouth with waterproof belt around 2 laps, PVC belt around the bag 2 laps cover. B, if there is no heat shrinkable tube, the 3 m waterproof belt (2228#) wrap around the joint, covering the original sheath fracture 10cm, around the bag 2 back and forth. Cover one back and forth with an insulating strap, and finally cover a back and forth with a PVC strap.

Precautions related to intermediate connectors.

1. When purchasing intermediate joints, pay special attention to the quantity and quality of J-30 insulating glue and semi-conductive tape,

Try to choose the use of large contact area, through tin or galvanized process treatment of the standard intermediate joint. In the case of good process control, cold shrinkage cable accessory seal waterproof should be better than hot shrinkage cable accessories, you can give priority to the full cold shrinkage intermediate connector

2, in the outdoor production of high-pressure intermediate joints, air relative humidity should be 70[%] below, humidity can improve the ambient temperature or heating cable. 100KV or more of the intermediate joint construction should be built temporary shed, the ambient humidity is strictly controlled, the temperature should be 10~30℃, to prevent dust, debris fall into. Construction in fog or rain is strictly prohibited

3, the design should consider the cable length requirements, as far as possible to avoid the use of intermediate connectors, must use intermediate joints, should be on both sides of the cable connector and adjacent cable 2~3m long section of the application of fireproof paint or fireproof tape.

4, the cable intermediate joint must have high insulation strength and large enough mechanical strength, in order to resist all kinds of mechanical stress and short-circuit current impact electric power, the joint at the long-term environmental moisture impact, should be reliable sealing.

Seal

Sealing includes two layers of meaning: one to moisture-proof, two to try to avoid the existence of Air gap.

(1) The water content of crosslinked polyethylene insulated cable is a subject which has been paid more attention in the international and domestic countries in recent years. The water contained in the insulation will cause the water branches to form in the insulator, resulting in insulation damage. Water branches are discharge pathways consisting of many microscopic water-filled voids less than a few microns in diameter, and the combined action of electric fields and water forms water trees. Therefore, the power cable in the installation, operation process, not allowed in the conductor, insulation layer in the presence of water, air or other impurities. These impurities are prone to ionization under the action of high-strength electric field, charged particles under the action of alternating electric field, so that the cable insulation layer in the course of operation gradually aging leading to breakdown, resulting in cable failure, so sealing work-must be done well. Each phase composite pipe at both ends and inside and outside the casing should be sealed to fill the sealant, to achieve effective moisture-proof. When the hot shrinkage pipe is coated with sealed metal parts such as connecting tubes and metal sheath, the metal parts should be heated to 60-70 degrees Celsius in order to obtain a good sealing effect.

(2) In order to reduce the existence of air gap, we can do the following: ① the insulating end into a cone to ensure that the winding filler and insulating end can be well bonded; ② evenly coated with a layer of silicon fat paste on the main insulating surface to enhance the sealing function; ③ composite pipe at both ends to wrap around the sealant; ④ to backfill the filler before installing the internal and external sheath, Fill the SAG, so that the whole joint presents a neat appearance, with PVC tape winding tight; ⑤ internal and external sheath installation to wrap at both ends of the sealant.

The above several problems in the field work are complementary, each process is connected to each other, mutual influence, we have to take them as a continuous whole to see.

The basic structure of 10,000 KV crosslinked polyethylene cable is certain, the cable intermediate head is made with reference to the installation instructions, to achieve the process specification and in accordance with the construction process construction, then the quality of the cable intermediate joint can meet the requirements of long-term safe operation.

热缩管及其他绝缘体处理电缆中间接头

电缆中间接头的安装步骤

   1,电缆的预处理工作

   2,导体连接

     剥线不要损伤导线，接头错开防短路，用液压钳压好。

   3,内半导电层恢复

   4,绝缘层恢复

     有机硅胶+自粘防水胶带—》热缩管—》绝缘胶带（可加强绝缘处理）。

   5,外半导电层的恢复

   6,金属屏蔽层的恢复

   7,铠装层的恢复

   8,保护套的恢复

低压电线电缆硅胶电线中间接头的防水处理步骤

   1）端子压接好以后，在端子周围缠绕防水填充胶。收缩热缩管。

   2）如果是一般略微潮湿的环境，就在电缆两端分别缠绕上防水填充胶带，收缩护套管（护套管两端必须带胶）即可。

   3）如果环境比较恶劣，就必须使用自粘性防水胶带进行加强防水（也可以使用热缩防水胶带，我们一般都用自粘胶带，热缩胶带处于用于电缆破损修补）。方法是：A，填充完防水填充胶以后，在填充    胶外层用自粘防水胶带缠绕一层或者拉长自粘防水胶带缠绕多层，但厚度不要太厚，以免太大了导致绝缘管套不进去。B，将热缩管套在胶处收缩好。C，在热缩管两端缠绕防水胶带，然后再缠绕一层自粘防水胶带，在电缆绝缘护套的两端缠绕防水胶带和自粘胶带，然后将护套管加热收缩完毕即可。

 中间接头通常来说指的是电缆中间接头，即电缆线路中间部位的电缆接头。中间接头是用于各种电压等级的交联电缆或油浸电缆的中间连接的电缆附件。主要作用是使线路通畅，使电缆保持密封，并保证电缆接头处的绝缘等级，使其安全可靠地运行。

中间接头的制作

   1.如果能在当地买到质量不错的热缩管,可以将热缩管先套到某一段电缆上。注意:热缩管的直径最少是原来电缆直径的1.5倍

   2,在电缆准备接头的地方挖电缆井(人孔),便于施工及维修;在接头以前检查电缆断头是否受潮;切去受潮部分。

   3,两根电缆分别敷设到位,接头处电缆摆放平直,并且重叠,以便切去端头部分。(因为断口的导体可能不圆,穿不进接管)

   4,在准备接头的位置做好标记(定中心),在此标记前3-5cm处切去多余电缆。(因为各相是绞和在一起的,分开后的长度会不一样,要根据需要再最终定位)

   5,根据接头需要,从电缆断口开始依次剥去外护套,铠装层。注意:剥铠装层的时候不要伤到绝缘。

   6,将各相分开,剥去绝缘层,开剥长度为:接管长度/2+3~5mm。注意:剥绝缘的时候不要伤到导体。

   7,清洁导体;压接。压接次数,压接顺序及间距参照GB14315的规定。

   8,擦去多余的抗氧化剂。

   9,使用3M绝缘胶带(23#)恢复绝缘层,胶带的厚度为原来绝缘厚度的2倍。注意:胶带使用方法按照说明操作,来回绕包.

   10,用PVC胶带覆盖绝缘带,绕包一个来回。

   11,恢复铠装层的电气连接。如果有3M铠甲带,可以采用铠甲带。建议采用镀锡铜编织线跨接,两端用铜扎丝帮扎。有条件的话焊锡。

   12,A,如果有热缩管的话,将热缩管拉到接头处,热缩,两端口用防水带绕包2圈,PVC带绕包2圈覆盖。 B,如果没有热缩管,将3M的防水带(2228#)绕包到接头处,覆盖原护套断口10cm,绕包2个来回。用绝缘带覆盖一个来回,最后用PVC带覆盖一个来回。

中间接头的相关注意事项  

   1.选购中间接头时，特别要注意J-30绝缘胶、半导电胶带的数量和质量，

    尽量选择使用接触面积大，经搪锡或镀锌工艺处理的标准中间接头。在工艺控制好的情况下，冷缩电缆附件密封防水性应优于热缩电缆附件，可以优先考虑全冷缩中间接头

   2,在室外制作高压中间接头时，空气相对湿度宜为70[%]以下，湿度大时可提高环境温度或加热电缆。100KV以上的中间接头施工时应搭临时工棚，环境湿度严格控制，温度宜为10~30℃，防止尘埃，杂物落入。严禁在雾中或雨中施工

   3,设计时应该考虑电缆长度要求，尽量避免使用中间接头，必须使用中间接头的，应在电缆接头两侧及相邻电缆2~3m长的区段内施加防火涂料或防火包带。

   4,电缆中间接头必须具有高绝缘强度和足够大的机械强度，以抵御各种机械应力和短路电流的冲击电动力，接头处长期收环境潮气影响，应有可靠的密封性。

密封

   密封包括两层含义：一要防潮，二要尽量避免气隙的存在。  

   (1)交联聚乙烯绝缘电缆含水是近几年来国际国内比较重视的一个课题。绝缘中含水会引发绝缘体中形成水树枝，造成绝缘破坏。水树枝是直径小于几个微米的许多微观充水空隙所组成的放电通路，电场和水的共同作用形成水树。所以电力电缆在安装、运行过程中，不允许在导体、绝缘层中存在水分、空气或其他杂质。这些杂质在高强度的电场作用下容易发生电离，带电粒子在交变电场的作用下，使得电缆绝缘层在运行过程中逐渐老化导致击穿，从而引发电缆故障,所以密封工作—定要做好。每相复合管两端及内、外护套管两端都要密封填充密封胶，达到有效防潮。热缩管件包敷密封金属部位如连接管、金属护套时，金属部位应予加热至60-70摄氏度，才能获得良好的密封效果。  

   (2)为减少气隙的存在，我们可以做以下工作：①将绝缘端部削成锥体，以保证包绕的填充胶与绝缘端能很好的粘合；②在主绝缘表面均匀涂一层硅脂膏增强密封的作用；③复合管两端要包绕密封胶；④在安装内外护套前要回填填充物，将凹陷处填平，使整个接头呈现一个整齐的外观，用 PVC胶带缠绕扎紧；⑤内外护套安装时要在两端缠绕密封胶。  

  以上几个问题现场工作中都是相辅相成的，每道工序都是互相衔接、互相影响的，我们要把它们作为一个连续的整体来看待。

  10千伏交联聚乙烯电缆的基本结构是一定的，电缆中间头制作时参照安装说明，做到工艺规范并按照施工工艺施工，那么电缆中间接头的质量就能满足长期安全运行的要求