Proposals for an improvement in transformer diagnosis using dissolved gas analysis (DGA)

The diagnosis of oil-immersed transformers using the dissolved gas analysis (DGA) technique has been well accepted and widely used. IEC Publication 599 touches on the diagnosis of faults involving paper insulation based on the ratio of CO/sub 2//CO. It states that a fault involving paper insulation is probable when the CO/sub 2//CO ratio is 3 or lower; we would like to propose a figure of 10.