Related Post

What is called “Barrier joint” of cable ?Interview Question of Underground Cable What are varnished cambric insulated cables ?What do you mean by XLPE cable and what are its advantages over conventional cables ?What do you mean by MIND cable and where is it used ?What do you mean by the term “Sheath losses” ?What is the procedure of reducing the sheath losses in sheaths of the three single core cables in a 3-phase system ?What do you mean by the term “Dielectric losses” ?What do you mean by thermal resistance of a single core cable ?What are the load conditions of an underground cable ?what special cares are to be taken for storage of cable drum ?What are the methods of cable laying ?What is soil thermal resistivity ?What is proximity effect ?What are the procedures to be adopted for determining the types of cable faults ?What precaution should be taken while taken a cable through trenches in the following locations (a) Road crossing, (b) Railway crossing & (c) Crossing of water mains ?What is called “Heat shrinkable joint” of cable?What can be the causes of damage to PVC cables and paper insulated cables?

Index

SymbolsTransformerRelayPower-SystemBasic-electricalACSR-ConductorCircuit-BreakerInterview-questions-of-Basic-ElectricityInterview-questions-of-transformerInsulatorCurrent-TransformerMCQMCQ-powersystemThermal-power-stationInterview-questions-of-Power-SystemPower-ElectronicsInterview-questions-of-Underground-CableInterview-questions-of-IlluminationIlluminationMCQ-of-ElectronicsMCQ-of-Basic-ElectricalMCQ-of-Transformers MCQ-of-D.C-motor MCQ-of-D.C-generatorsMCQ-Control-SystemMCQ-Measurementsmcq-of-Generation-power-systemMCQ-of-Induction-MotorMCQ-of-Transmission-DistributionMCQ-of-Electrical-MachinesMCQ-of-Alternator-and-Synchronous-MotorsMCQ-Electric-Power

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


≪ Previous Next ≫

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.


≪ Previous Next ≫


Related topics :


Recent Post

Multiple Choice Question (MCQ) of Transmission and Distribution page-3:
21. ACSR conductor implies
A) Anodized Core Smooth Run
B) Anode current sinusoidally run
C) Aluminium conductor steel reinforced
D) All conductors surface treated and realigned.

Read more...

Multiple Choice Question (MCQ) of Transmission and Distribution page-2:
11. In overhead transmission lines the effect of capacitance can be neglected when the length of line is less than
A) 80 km
B) 100 km
C) 160 km
D) 200 km.

Read more...

Multiple Choice Question (MCQ) of Transmission and Distribution page-1:
1. Which of the following is not the transmission voltage in India ?
A) 400 kV
B) 264 kV
C) 132 kV
D) 66 kV.

Read more...