Novel winding for a gas-insulated transformer

There are numerous operational problems with the technology of oil-filled t ransformers including their considerable mass and associated civil engineer ing. In addition, blast walls, acoustic baffles or sufficient space are req uired to protect surrounding buildings in an urban environment. In an attem pt to answer these problems, a 20kVA, single-phase prototype gas-insulated transformer, that employs atmospheric air as its cooling and insulating med ium and uses a novel woven winding, was designed and built. This has clearl y demonstrated the feasibility of woven winding, gas-cooled transformers th at can operate at an average current density of 2.4A.mm(-2) without the aid of powered cooling systems. Success was due to the use of a novel woven wi nding comprising a copper warp and a PTFE weft. As a consequence of the imp roved gas flow through this winding and the absence of any insulating cover on the copper strands, the thermal characteristics have been enhanced to a point where this technology is comparable with that of conventional oil-pa per insulated transformers, without the accompanying weight, cost and envir onmental considerations associated with the latter.