Problems of increase in operating reliability and ecological compatibility of medium voltage XLPE cables

Currently, cables of new generation with cross-linked polyethylene being increasingly applied in domestic medium-voltage distribution systems. In Russia, cables with XLPE insulation are not so widely spread yet - the volume of XLPE cables is equal to 2% of the whole cable park. Nevertheless, manufacturers will practically completely turn to the production of XLPE cables instead of conventional ones - cables with impregnated-paper insulation - in the nearest 3-5 years. The main advantages of XLPE cables are: considerable factory length, which reduces the number of joint boxes and circumstantially increases operating reliability of cable lines; enhanced carrying capacity due to the increase in cross-section of a single-phase cable conductor up to 630-1000 mm2 and higher (by 15-20%) current load governed by an acceptable working temperature of XLPE insulation up to 90degC; high speed of assembling and maintainability of XLPE cables in using cable fittings on the basis of thermocontracting composite materials; low acceptable temperature in laying cable without preliminary heating, the possibility to install the cable with unlimited differences of path elevation, as well as more ecological assembling and operation (due to the lack of lead, oil, and bitumen); by assurance of foreign manufacturers, the failure flow by a factor of 102 lower in comparison with impregnated-paper cables.