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RWTH Aachen University

Using a digital twin to improve the predictive maintenance of critical electrical machines

1 Jun 2024

Digital twins of electrical machines are proving to be cost-efficient tools for the management of sensitive, or critical equipment. Monitoring conditions remotely and automating diagnosis – often tailored to the individual machine – can lead to the early detection of faults and aging effects, thus enabling preventive maintenance that extends reliable oper-ation, even under varying speeds, loads, and environmental conditions.

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Results from the digital twin show (left) accurate prediction the transient signals under no-fault conditions and (right) disparities for different fault conditions.

A digital twin to detect disparities

The Institute of Electrical Machines (IEM), at the RWTH Aachen, is developing a monitoring system that can be applied to determine the changing insulation condition of motors. The approach combines data from electrical sen-sors and sophisticated modelling, to predict faults before they impact operation.

The digital twin applies high frequency modelling technologies to calculate the expected common-mode current, based on the voltage signals measured. The simulated current (which represents fault free conditions) is then compared with a real-time measurement. The disparity between the simulated and measured transient behaviours during switching show alterations in the parasitic capacitances that indicate stator winding deterioration. 

Validated insights

Experimental data has validated the high accuracy of the simulated transient signals, and the sensitivity of the system for effective, real time detection of even small changes. The trend of the disparities between the simulated values and the measured voltage and current signals provide valuable insights into thermal and electrical aging processes, and make it possible to proactively avoid device failure.