Short for cross-linked polyethylene, XLPE is used for insulation for high voltage cables. This sturdy and strong material is used in a number of hostile conditions — from heating systems to pipe for chemicals, sewage and slurries. XLPE’s construction gives it its unique properties that make it one of the toughest materials.
The first time XLPE was manufactured was in 1930s. The manufacturing process was too expensive to be used for commercial purposes. Since then new methods have emerged. Technology has enabled XLPE power cable manufacturers to streamline this process and make it economical.
XLPE is manufactured through a cross-linking process. This is a delicate process where any mistake can make the end product either too brittle. XLPE is made from polyethylene under high pressure. Organic peroxide is added as additive. Heat and pressure are applied to cross-link the molecules. The process changes the thermoplastic into an elastic material.
What makes XLPE suitable for high voltage cable insulation?
XLPE is often used in power transmission and distribution lines because it is highly suitable for the task. Its construction gives it certain unique properties that make it ideal for high voltage cables. These are:
Ability to carry high voltage: The cross linking in its manufacturing process makes it resistant to heat. This makes it stable even in extreme heat, allowing it to withstand high operating temperature. This gives the XLPE cable high current rating. It can voltage ranges from 600V to 35kV.
Flexibility: XLPE has high flexibility and can be easily be wound into turns, both wide and short radius. This makes it suitable for places where we need tensile strength and cables that have to be wound up.
Low maintenance: XLPE can withstand heat and heavy wear and tear. It also requires almost no maintenance.
No sheath required: XLPE has very high electrical and water resistance. This means that it has no requirement of external sheathing for extra protection. This frees it from problems that come from sheathing, such as corrosion.
Easy installation: Despite its strength and sturdiness, XLPE is not heavy. This makes it easy to install at a height. Lack of metallic sheathing and flexibility adds to this ease.
Structure of XLPE cables
Medium and high voltage XLPE cables typically have a single core construction with a circular conductor. Stranded copper or aluminum is used for the conductor. Some cables also have a conductor screen, filling the space between the conductor and the XLPE insulation. This also reduces the electrical stress, making it possible for the cable to carry high voltage.
XLPE Vs PVC
XLPE is usually seen as a suitable replacement for PVC cables. PVC is thermoplastic where XLPE is thermosetting. Both find wide usage because of their high resistance to heat.
- Both can have single as well as multiple stranded cores. But PVS is usually more flexible
- XLPE is used for low as well as high voltage current. PVC is usually only used only for low tension current carrying applications.
- PVC is available in shielded version, but XLPE is rarely shielded. But that is usually due to its high strength and resistance. XLPE is even resistant to UV light.
- XLPE’s resistance to various environmental factors, in fact, is higher than that of PVC. It is resistant to environmental stress and cracking.
- PVC wires are cheaper than XLPE.
Selecting XLPE power cable manufacturers:
XLPE has many superior qualities. But it is critical that the manufacturer is selected carefully.
- Look for certification: Cables must carry the required ISO certification. This is indicative of the quality and safety of the cables. For the average user, this is the only way of ascertaining the quality of the cable because certification means that the cable has gone through some form of testing. You can also check for international standards like IEC, CENELEC, and ICEA.
- Check the specifications: XLPE is only the insulation. So, you are essentially looking for the right wiring. This will depend on the task at hand. Check the specifications and then select the right cable.
- Check the voltage capacity.
- Check whether you need single or multiple core cable. A multiple core cable is more flexible.
XLPE cable are usually brought for long-term use. So, invest in a good quality cable from a reliable XLPE power cable manufacturer.