Failure mode for AC drives on high resistance grounded systems

High resistance grounding (HRG) is the preferred method of grounding in several industrial power distribution systems because of safety and reliability concerns. In this paper, a failure mode for AC drives on HRG systems is investigated. The cause of the failure is identified to be due to the interaction between the EMC circuitry of the drives. Simulation and experimental results are provided to demonstrate the failure mode. User manuals of several drive manufacturers are reviewed and recommendations for operating drives on HRG systems are provided