Cables generally work under natural cooling conditions, namely, to maintain the stability of heat by natural cooling. Sometimes, the cooling is not enough, which requires further cooling, to improve the transmission capacity. Using artificial accelerated cooling for cable is called the artificial cooling of the cable (or called forced cooling). There are many methods of artificial

cooling:

According to the cooling area relative to the part of the cable can be divided into two major categories of internal cooling and external cooling. According to the different cooling mediums can be divided into oil, water cooling, air cooling, cold, and another cooling medium such as freon evaporative cooling, etc.

Such as the center of the oil-filled cable after oil, is not only the added oil, insulating oil and under the action of the pump, circulating cooling, heat away part of the cable conductor, this method is called internal oil cooling. If the cable cooling water pipeline parallel, or during a cable tunnel in the cold wind, belongs to the external cooling.

Using the center has a good cooling effect on the cooling oil duct because the cooling medium is directly on the conductor of the highest temperature for cooling. But the conductor at a high potential, import, and export structure of the cooling medium is more complex. The Center often very does not allow oil duct diameter, cooling pipe pressure drop limit of the length of the cable. General short high voltage cable system with central oil passage for cold.

Cold outside the pipe diameter is less restrictive, cable joint is simple and suitable tor long cable system. When external cooling through cable heat along with the thermal resistance of each part, but also through the cable to the thermal resistance between cooling pipe, so the high cooling efficiency is not like the cold.

---ZMS Cable