A Comparative Investigation of Interturn Faults in Induction Motors Suggesting a Novel Transient Diagnostic Method Based on the Goerges Phenomenon

Early interturn short circuits are among the most challenging faults to detect in electrical machines. It is not only difficult to identify the fault, but the diagnosis and decision-making time are crucial since the severity of this fault increases very fast, leading to a catastrophic breakdown. Despite the importance of this fault's prompt detection, it has been lately shown that classical methods may be insensitive to early severity conditions leading to false-positive diagnostic conclusions. This article investigates the validity and reliability of current-based approaches to those utilizing the magnetic flux performing a comparative critical assessment. The work is carried out with a finite-element analysis and experimental testing while both the steady-state and transient operations are examined. The article demonstrates the incapability of classical approaches to reliably detect early interturn faults while flux-based methods prove to be sensitive and superior to the current-based ones at the steady state. Moreover, a transient method based on the Goerges phenomenon is proposed in the article for the first time.