ABSTRACT The increasing penetration of renewable energy sources into power grids introduces significant harmonic components in load‐side power supplies. Under nonsinusoidal supply conditions, the applications of conventional reduced‐order models of three‐phase induction motor (IM) lead to substantial inaccuracy in transient simulations as they are unable to account for these harmonics, adequately. To resolve this issue, this study investigates systematically the applicability of the third‐ and first‐order conventional models for transient simulations considering nonsinusoidal supply conditions. Subsequently, the improved fifth‐, third‐ and first‐order equation as well as the corresponding harmonic equivalent circuits of IM are derived considering the nonsinusoidal supply. For an 11, 000 kW IM and a 5.5 kW IM, this study compares the performances of the proposed and conventional reduced‐order models in simulating the typical transients including the start‐up, suddenly loading, locked‐rotor and normal steady‐state operations. The results demonstrate that the third‐ and first‐order conventional models are suitable only for calculating speed dynamics while they produce significant errors in the predictions of electromagnetic dynamics. In contrast, the proposed third‐ and first‐order models calculate accurately the electromechanical transients of IMs with nonsinusoidal supply, and the calculated results show excellent agreement with those by the fifth‐order reference model. The proposed harmonic models of the 5.5 kW IM and the 11, 000 kW IM are validated with the test results and the finite element simulation results, respectively.
Kang et al. (Thu,) studied this question.