Failure Mode for AC Drives on High Resistance Grounded Systems

Abstract

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.

Ground Leakage Current Caused by Common-Mode Voltage of PWM inverter

“…The harmonics of inverter's DM voltage in the phase-tophase voltages of the inverter are shown in Table 2 (No. [1][2][3][4][5]. It shows that the amplitude of the basic harmonic of phase-to-phase voltage uph-ph at frequency 25 Hz is greater than the amplitude of the phase voltage uph and is (15):…”

“…Two-level voltage PWM inverters are commonly used for supplying three-phase induction motors in industrial lowvoltage networks and for traction motors in the DC and AC railway traction. Lack of effective methods for reducing the negative impact of parasitic CM and DM voltages is the cause for increased risk of fault to loads powered from a common transformer [2][3]. In addition, there is risk of electric shock related to the leakage current caused by the CM voltage in inverters.…”

A method for impact assessment of faults on the performance of field-oriented control drives: A first step to reliability modeling

“…Definition of fault models, which is key for fault-tolerant design, is extensively discussed, including inverter faults [4], control faults [5], supply faults [6,7], and motor faults [8]. Aspects of fault detection and isolation have been extensively analyzed (see, e.g., [4,[9][10][11][12][13][14][15][16]).…”