Induction machine diagnostics using zero sequence component

Induction machine diagnostics using zero sequence components is presented in this paper. Electrical faults cause asymmetries in the phase impedances, producing a zero sequence voltage in wye-connected machines and a zero sequence current in delta-connected machines. The proposed measurement method identifies these well defined components in the zero sequence voltage/current and uses them to provide reliable information on the condition of the machine, with low sensitivity to the load level of the machine or variations in the phase voltage. The method can be used for the diagnosis of stator winding faults and broken rotor bars, and is valid both for line-connected and inverter-fed machines.