Vacuum Pressurized Impregnated Dry Type Transformer (VPI) Rating 63 kVA to 5 MVA Voltage ClassUp to 33 kV Frequency 50/60 Hz No of PhaseSingle & Three Phase Cooling AN & AN/AF Vector Group As per customer requirement Winding Material Cu / Al Tapping OCTL, OCTC, OLTC Insulation Class F/H/R Applicable Standards IS 11171, IEC 60076-11, IEC / EN 61378, EN IP protection IP 23, IP 33, IP44; smaller ratings up to IP54 Default accessories: Surge arresters, space heaters, temperature sensors / Indicator,anti-vibration pads, etc.