what are its advantages over conventional cables ?-ce certification renewable cable

What do you mean by XLPE cable and what are its advantages over conventional cables ?

XLPE cable means cross linked polyethylene insulated aluminium conductor armoured cable. In XLPE cable stranded aluminium conductor is first screened in the form of a semi conducting extrusion which provides a smooth conductor surface and prevents formation of cavities at the surface of the conductor when the cable is subjected to bending. The screened conductor is insulated with extruded XLPE compound. The insulation is further screened with layer of nonmetallic semiconducting material and over that a non magnetic metallic screen in the form of copper or aluminium tape is applied. In case of multicore cables cores are laid together with suitable filler in the interstices and wrapped with PVC tapes or extruded PVC. For mechanical protection non magnetic aluminium wire/ strip/tape armour for single core cables and steel wire armour for multicore cables are provided over the inner sheath. A layer of PVC/PE is extruded as outer sheath usually in back colour to prevent ingress of moisture. The space feature of the XLPE insulation is that long molecular chains of polyethylene are cross linked to each other by means of a process similar to vulcanisation of rubber and thus forming a three dimensional network structure with strong bond. Pure polyethylene is a thermoplastic material i.e. it becomes soft and plastic on heating and hard on cooling. Pure polyethylene is converted into thermosetting XLPE i.e. it sets permanently when heated. By cross linking process the polyethylene insulation of the cable is made thermally stable and also the melting point is greatly increased. So XLPE insulated cable has better resistivity to thermal deformation for its higher thermal tolerance property. Due to excellent thermal properties the current carrying capacity of XLPE cable is higher than that of conventional cable. XLPE insulation has higher dielectric strength compared to other conventional dielectrics used for cables resulting low dielectric loss. XLPE cable is made suitable for high voltage and extra high voltage application puto 132 kV. This cable can be used for long cable routes in high voltage transmission where the dielectric losses play a major role. This cable can easily be hadled due to lighter in weight than any other high voltage cable. As there is no case of oil migration from insulation it can be installed for inclined or vertical runs without any hesitation. XLPE insulation is highly resistant to moisture for which no special precaution is needed at the time of jointing & termination. The joining of XLPE cable needs less time than that of any other conventional cable of similar grade. These cables can safely be used on any vibrating layouts like bridges. These cable have the better resistance to salinity of water in the ground, chemicals, oils and corrosive furnes. These are free from fire risk. These cables are not prone to failure due to ageing characteristics and have longer life.

21/35kV MEDIUM VOLTAGE XLPE INSULATED MULTI-CORE STEEL TAPE ARMOURED CABLE

PVC vs. XLPE: Comparison of Two Most Popular Cable Insulations

Electric cable conductors need to be electrically isolated from other conductors and the environment to prevent short circuits. To do so, we extrude a layer of insulation around the conductor.

Here, we examine Polyvinyl Chloride (PVC) and Crosslinked Polyethylene (XLPE), which are the two most common insulation materials used in the cable industry.

Why PVC Insulation?

PVC is the most widely used insulation material in power cables.

This is because PVC insulated cable is 1) a cost-effective material for electrical and physical protection for standard low voltage building cables, and 2) has a small bending radius, and hence is very easy to install in narrow places.

Applications for PVC cables include general low voltage cabling such as lighting and general building use.

However, standard PVC has certain limitations. 1) Standard PVC has a maximum operating temperature of 70°C and 2) it is not as hardy a material when it comes to resistance to water and environmental stress cracking (ESC).

When should you choose XLPE Insulation?

XLPE has a maximum operating temperature of 90°C and this means that if we compared an XLPE insulated cable and a PVC insulated cable for the same conductor size, an XLPE insulated cable would be able to carry a higher current load. This also means that based on your current load requirements, there may be instances where you would be able to select a smaller cable size if you used an XLPE insulated instead of a PVC insulated cable.

XLPE is a hardier material compared to PVC due to the crosslinking process. XLPE provides greater tensile strength, elongation and impact resistances compared with PVC. This cross linking process also enhances the material’s resistance to oil and chemicals even at elevated temperature; this makes XLPE a popular pick as insulation for LSZH Flame Retardant or Fire Resistant cables.

Applications for XLPE insulated cables are therefore popular as main risers in buildings, LSZH flame retardant and fire resistant cables, as well as beyond low voltage applications such as medium to extra high voltage.

The table below shows a simple comparison of the properties of these materials.

Speak with our sales if you would like more information on what to choose for your requirement.

FAQ: The benefits of XLPE insulated cables

XLPE vs PVC cable insulation

XLPE is suitable for voltage ranges from low to extra high voltage, surpassing other insulation materials such as PVC, Ethylene Propylene Rubber (EPR) and silicone rubbers. Cross-linking the polyethylene also enhances the chemical and oil resistance at elevated temperatures and makes it suitable for use as a Low Smoke Zero Halogen material.   

The mechanical properties of the XLPE are superior to many other insulations, offering greater tensile strength, elongation and impact resistances. The addition of carbon black can be used to further enhance hot deformation and cut through resistance. The XLPE insulation will not melt or drip, even at the temperatures of soldering irons, and it has increased flow resistance and improved ageing characteristics.

Improved water-tree resistance is another benefit of XLPE insulation for LV cables and MV cables over PE insulations. Water treeing is a defect which is the result of imperfections in the insulation where fracture lines occur and grow in the direction of the electric field, increasing with electrical stress. It should be noted that this effect is not limited to PE materials.