Resin Cast Current Transformer

Resin Cast current Transformers are dry type transformers the active part of which is completely embedded in quartz loaded epoxy resin by using Vacuum moulding technique. After moulding the resin is hardened by polymerisation. The main insulation between primary and secondary and earth is obtained by this epoxy resin and hence CTs have a lot of technical advantages.ADVANTAGESUse of epoxy resin for insulation? Compact design for high mechanical and dielectric properties. The considerable reduction in dimensions reduces space and switchgear panel width. ? No fire spread and hence no permanent damage to the equipment; Even after a surface flashover reconditioning is easy by a thorough cleaning of surface. ? Epoxy is non hygroscopic and hence gives very good insulation properties even in severe humid conditions. ? Non ageing. The moulding has a non wearable glossy surface and has a very high degree of toughness. 1) Therefore the CT requires no maintanence except for the clearing of dust contamination on the surface. ? As there is no oil for insulation the CT can be mounted in any direction to suit the switchgear design. ? The current terminals are provided with sufficient area thereby avoiding any overheating of joints. ? Based on the dynamic current rating additional clamping facility is provided for the terminals. ? For higher current ratings window tupe CTs type WR can be used which will give additional saving in space required for terminal connections. ? For window type CTs equipotentialising facilities are provided with cast nuts and thereby permanent and sure connections can be made. ? For window type CTs large window openings are provided so that the busbars can be run through without any special bending and with one thickness gap between individual bars as done in the switchgear. ? Sufficiently long creepage surfaces are provided to ensure better surface tracking properties.