It differs from oil-filled transformers according to the cooling method used. The HT windings are vacuum-cast epoxy resin-coated transformers. LV windings are transformers that can be manufactured using both the cast resin method and the pre-impregnated resin method. They are produced in a power range of 25-25,000 kVA, up to a voltage level of 36 kV, with a choice between natural air cooling (NA) and fan cooling (FC). The utilisation of a cooling fan can increase power by up to 40%.