XLPE cable

XLPE(Cross Linked Poly Ethylene) Cables have advantages over conventional paper insulated/ Oil filled cables

í          Lower dielectric losses

í          Lower weight

í          Higher permissible continuous and short circuit current withstand capacity

í          Environment friendly - no risk of oil leakage in to environment

í          Easy installation of accessories

í          Maintenance free

í          No problem with vertical  installation

í          Improved flame retardant  property with PVC sheath, due to absence of any oil etc.

Manufacturing range

í          Cable sizes                                          : 95 sq mm - 2000 sq mm

í          Voltage grade                                    : 66 kV - 220 kV (extendable up to 400 kV)

í          The basic material for XLPE is low density polyethylene(LDPE)- which is thermoplastic. For EHV, the cross linking takes place in an electrically heated tube of extrusion line , in an inert gas atmosphere.The gas pressure in tube is kept around  5-10 bar to avoid formation of voids due to peroxide decomposition.

Purpose of cross linking

î          To improve thermal  rating - continuous , overload & short circuit temperature ratings

î          To improve mechanical properties

î          To improve deformation resistance

Property                                                                     PE                           XLPE

Max  continuous operating temperature ( °C)                            70                           90

Max  short circuit temperature                ( °C)                         150                         250

Dielectric constant                                                                    2.3                          2.3

Dielectric strength(kV/mm)                                                     > 22                        > 22

Tan d                                                                                   0.0005                   0.0005