XLPE power cable is a type of polyethylene cables that have cross-links. It is used extensively in domestic infrastructure. It has an extremely high resistance to a number of corrosives and is hence, used in very hostile environment. It replaced PVC and CPVC as the chosen insulating material. XLPE power cable is preferred over other alternatives because of its excellent electrical properties and low dielectric loss factor. For instance, it can tolerate higher voltages than PVC.
Applications of XLPE Power Cables
We find XLPE cables all around us — underground, overhead, in power stations, cable ducts, on the ground and offshore. The unique properties of XLPE allow us to use these cables where we have very unique or aggressive conditions and we need cables to function under such demanding situations. These include situations with
- High ambient temperatures
- High short-circuit currents
- High emergency loads
- High sun exposure
- High earth leakage currents
- Cables ducts
- Bunching or grouping of cable
The origin of XLPE cables can be traced back to 1930 when PEX materials were developed by extruded tube was irradiated with an electron beam. However, this was quite an expensive process at the time. The cross-linking method came later, in the 1960s. Consequently, the processing technology was developed and made both functional and economic for mass production, eventually becoming quite commonplace.
Why are XLPE cables preferred?
Ability to work under high heat: Cross linking in the XLPE hinders the movement of molecules, especially under high heat. This ability gives the cables high stability when the normal temperatures get very high. This is especially useful in high load when the high temperatures can cause overheating. Other cables will melt under such conditions. Even PVC, a high quality plastic, will melt if the temperatures rise too much. In contrast, XLPE cables can retain their integrity for longer.
Large current carrying capacity
XLPE cables are the preferred option when we are working with large currents. Most cables will usually start to wear down quickly when carrying large currents. But XLPE power cables ability to disperse the heat within its structure means it can carry high electricity and fluctuations without melting or any other adverse effects. Consequently, it is used when carrying large currents, emergency current loads and in short circuit conditions.
XLPE is made of very lightweight resin. Like other plastics, such as PVC, the strength of XLPE is rarely connected to its weight. This is why even in heavy duty applications, XLPE cables can remain lightweight.
XLPE cables can withstand bending at very small radius. This gives the cable a flexibility which in turn, allows us to move it around as we see fit. A flexible cable is easy to install because we do not have to worry about cracks developing with coiling during transportation or frequent coiling and uncoiling. The light weight of the cable adds to its easy installation. Transportation is easy and laying it in difficult territories like offshore or overhead becomes easier. XLPE cables are also easier to splice or cut, which again adds to our ease of installation as we can easily use what we want without damaging the cable.
XLPE cables do not require any special considerations such as a limitation height profiles. In addition, these cables are very lightweight, which makes overhead installations easier. The cables are easy to carry to a height and then rolled out on installation. Unlike oil-filled cables, there are no dangers of oil migration.
XLPE is used for insulation because it has excellent resistance to even aggressive corrosive elements. It can bear very high degrees of exposure to sun, chemicals or biodegradable factors. This is why we see XLPE power cables in overhead power cable spread, offshore installations, and sewage plants and in cable ducts. In overhead cables it has better chances of withstanding constant sun exposure. In sewage tanks or chemical plants, it can bear aggressive action of chemicals. In offshore facilities, it can withstand the very corrosive salt water.
XLPE is a very tough substance that does not crack, melt or wear easily. It will not crack with frequent use and will withstand almost every corrosive element without wear and tear. It also retains its integrity under high temperature or voltage fluctuations without melting like other cables. This gives XLPE power cables very long durability.