Early Detection of Stator Inter-Turn and Single Phasing Faults in Induction Motors Using Negative Sequence Voltage Components

This paper presents a non-invasive threshold-based method for early detection of stator inter-turn faults (SITFs) and single phasing (SP) faults in induction motors by measuring the three-phase voltages at the motor terminal. These voltage signals are processed to extract the sequence components. The Negative Voltage Factor (NVF) is defined as the ratio of the magnitudes of negative sequence voltage <inline-formula> <tex-math notation="LaTeX">$\vert $ </tex-math></inline-formula>V<inline-formula> <tex-math notation="LaTeX">${}_{\mathbf {2}} \vert $ </tex-math></inline-formula> to positive sequence voltage <inline-formula> <tex-math notation="LaTeX">$\vert $ </tex-math></inline-formula>V<inline-formula> <tex-math notation="LaTeX">${}_{\mathbf {1}} \vert $ </tex-math></inline-formula>, and is used as a fault indicator. The proposed method uses a dual-threshold strategy: a lower threshold for SITFs detection and a higher threshold for SP faults detection by comparing with the VNF values. Unlike traditional current-based approaches, this voltage-based technique proves to be more sensitive and load-independent. Simulation results using ANSYS Maxwell and experiments in the lab for a 2.2 kW induction motor demonstrate the method&#x2019;s effectiveness to detect incipient SITFs and SP faults accurately under various motor loadings and fault severities.