[IEEE 1999 IEEE Africon. 5th Africon Conference in Africa - Cape Town, South Africa (28 Sept.-1 Oct. 1999)] 1999 IEEE Africon. 5th Africon Conference in Africa (Cat. No.99CH36342) - Modern methods performed in 400/200 kV substation-Iron Gates 1-for 400 MVA, 400/220/22 kV autotransformers rehabilitation in order to increase their installed life and their service reliability