Diagnostics of induction machines using the zero sequence voltage

Diagnostics of induction machines using the zero sequence voltage is presented in this paper. Both stator-winding fault and broken rotor bar detection are covered. Faults in the stator windings or damaged rotor bar cause asymmetries in the phase impedances of the machine, which give rise to zero sequence voltage components. The measured zero sequence voltage is shown to contain reliable information on the condition of the machine, with little influence from the operating point or imbalances in the phase voltages. The method will be shown to be valid both for line-connected machines and inverter-fed machines.