Cooling Effect by Gas Density of SF6 Gas Insulated Transformer

Natural gas circulation of SF6 gas insulated transformers and temperature rises of coils in case of natural and forced cooling are discussed theoretically in relation to gas density or filled gas pressure. The formulations of temperature rises, theoretically derived here, have been examined by experiments on transformers. The temperature rises of the gas and coils have a tendency to decrease at higher gas density. Based on these analyses, some studies of operation loads under lower gas pressure are also described in this paper.