Comparison of DC Ramp and DC step tests results on hydro generator stators

This work aims at comparing results obtained from the DC Ramp test with the DC step test on the stator insulation of large hydro generators. Four cases of field measurements done on hydro generators are presented. Results are analyzed according to analytical solutions presented by the authors in recent publications for both methods. Quantities such as IR, PI, absorption current parameters and leakage currents are tabulated for each case and various aspects regarding respective advantages and complementarities pertaining to each method are discussed.