Transformer fault detection

In electrical equipment containing insulating oil wherein fault gases may be generated, the improvement comprising means for detecting and measuring said fault gases, said means comprising a cell adapted to be located in a potential fault gas environment within said electrical equipment, said cell including an inlet manifold and an outlet manifold, a plurality of elongated hollow tubes, each of said tubes communicating respectively with said inlet and outlet manifolds, each of said tubes being permeable to gases but impermeable to liquids, hollow extension leads extending from said inlet and outlet manifolds, a portable analytical measuring device, means for removably connecting said hollow extension leads to respective inlet and outlet conduits in said measuring device, said measuring device including a gas chromatograph analyzing means, means in said portable measuring device for passing a carrier gas through said inlet conduit, through said hollow tubes, and through said extension leads and said outlet conduit for flushing into said gas chromatograph analyzing means a sample gas which is allowed to come to equilibrium in said cell, the minimum volume of sample gas in said cell at equilibrium being defined by the internal volume of said plurality of hollow tubes and said manifolds, said minimum sample gas volume being sufficiently large so that individual gases separated by said gas chromatograph analyzing means temporarily attain constant concentrations in said carrier gas, said constant concentrations being independent of said sample gas volume so that concentrations of individual fault gases in said sample gas can be measured without consideration of the actual volume of said sample gas.