Medium voltage EPR insulated rubber cable market application issues

1. Overview

The wire and cable industry is the basic industry of our country. Statistics for 15 years, China's wire and cable industry average annual growth of more than 15%. At present, the industrial output value of 600000000000 yuan, is the world's largest wire and cable production. But we should see that China is becoming the world's largest cable producer at the same time, not a power cable power. In the coming period, China's electric wire and cable industry will be in the best period of historical development, but at the same time, it will also face the challenge of intense competition and homogenization. 

Varieties of cable customers increasingly high demand, rising production capacity of supporting cable factory product comprehensive technical ability, special cable, EHV cable, wind cable, PV cable, ship with cable, power cable and other development is in the ascendant, especially middle voltage rubber cable is a lot of power cable factory fancy as investment highlights, have invested heavily in the development of the market, and trial production or supply market EPDM insulation of high voltage cables meet cable market and user's demand.

At the beginning of the twenty-first Century, China's cable material market has been specialized in the production of rubber cable material manufacturers. It has promoted the development of rubber cable and has laid a good foundation for the development of rubber cable. The author of the company for the medium voltage EPDM insulation rubber cable material production and application for many years to explore and develop, and achieved some results. 

But the cable factory extruded cables application process, did not pay attention to some details and caused the cable to appear quality problem, I had this to say about the views and reasons analysis, expect to be able to cause the attention of the majority of the production of cable factory, in the future development of the work gradually solve and improve.

2. The application of rubber cable in the need to pay attention to the problem

Encountered many problems in the production process, is the 35KV of the medium voltage cable material in the application process, for example:

2.1 To produce qualified medium voltage rubber cable, the first EPDM insulation material is the key, the use of EPDM medium voltage insulation material has the following technical requirements:

First, must choose suitable ethylene propylene rubber, vulcanization system, packing, and complexing agent, reasonable formulation technology, and correct mixed refining processing methods of production of products, guarantee the medium voltage insulation material quality, in all aspects of production to avoid impurities to enter.

2.2 Good product appearance, preferably cylindrical particle shape; no adhesion or irregular appearance of debris.

3. Have good processing properties; appropriate Mooney viscosity and scorch time.

White. Medium voltage insulating material must be the best way of packing, good sealing performance, and control products in the packaging, storage, transport and remove packets using the process to prevent impurity pollution, easy to use.

The EPDM, 26/35KV medium voltage insulation material performance must meet the following criteria (according to GB/T12706.3)

The maximum rate of change of weight is Mg/cm255

Material using 2.2 MV EPDM insulation should configure the appropriate hardware and correct processing

Firstly, the hardware configuration of the rubber extruder

Requirements with a rubber even sulfur lines or XLPE even sulfur lines, extruder, the compression ratio of 1.1:1 ~ 1.5:1, the length to diameter ratio of 15:1 to 20:1. Long 25:1 can also, for 10kV and above high voltage cable insulation by shielding, insulation, outer shielding layer, to reduce the partial discharge (PD) as much as possible should be produced by three layer coextrusion method, the steady thrust, so equipment requirements are relatively high, best imported three-layer coextrusion extruder, if the use of XLPE continuous curing production line, attention should be paid to the extrusion machine of screw configurations suitable.

The flow of granular materials form is most advantageous for impurity control. Therefore, medium pressure and particle are made of granular, so the hopper and a feeding device are necessary, the hardware must be matched, and packaging and transportation feeding are crucial.

Secondly, the extrusion temperature control

Material of EPDM rubber high ethylene content filled a small proportion, so pressure ethylene propylene rubber extrusion temperature was slightly higher than that of ordinary ethylene propylene rubber medium pressure ethylene propylene rubber insulation should normally be controlled in the range of 60 DEG C. Sometimes it can be as high as 120. Too low temperature will lead to the insulation material surface is not smooth and delicate, the temperature being too high will cause the glue to burn. Therefore, the temperature control system of the extruder requires accurate temperature control.

Third, the cross-linking temperature control

Medium pressure ethylene propylene rubber insulation material using peroxide curing system, available high-pressure steam at even the sulfur vulcanization can also be dipped in a salt bath vulcanization. Recommended curing temperature is 160-200. The concrete temperature is determined by the performance test results of the cable's extrusion speed and the degree of the insulation of the insulating material.

The insulation material in the process of using medium pressure, impurity control

First, a clean production site and production equipment are essential, if the production line at the same time, the production of XLPE insulation specifications or other rubber insulation, then the production medium voltage cable must be clear squeeze machine parts, because of the different material mixed with medium pressure ethylene propylene insulating material to produce consequences equivalent to impurities into.

Secondly, in the medium pressure ethylene propylene insulating material transport, storage, collar with the process should maintain packaging intact and avoid contamination of product packaging, in the use of materials removed bags, pouring or ceiling material conveying avoid impurity is a key step, try to avoid with unclean tools or hand feeding.

To sum up, the domestic ethylene propylene rubber insulation material can produce qualified rubber insulated cables. But in the process of production and testing, some problems that affect the quality of the cable can be encountered, and the problem can be solved by improving the management level of production. Cooperate in the professional production plant and rubber cable factory in the domestic rubber cable material, improve the quality level and promote the development of rubber cable.