M. Rasoulpoor, M. Mirzaie, S. M. Mirimani,
Volume 12, Issue 1 (3-2016)
Abstract
This paper investigates the effect of metallic sheaths on losses and temperature of medium voltage power cables. Two grounding methods of sheaths, including both ends bonding and single point bonding that causes different situations on cable ampacity, are considered. Electrical losses of cables that are main sources of heat are calculated in both conductor and metallic sheath of the cables. Sheathed and unsheathed medium voltage single conductor cables in flat and trefoil formations with different distances are considered, while calculated losses are compared in different constructions. Calculations of resistive losses are performed based on finite element method (FEM) and IEC standard formulations. The results of two methods are compared and analyzed. Moreover, the effects of eddy currents and circulating currents of sheath on total resistive losses are evaluated. Finally, thermal analysis based on FEM is executed to achieve maximum temperature of cable in different constructions. Simulation results show the importance of metallic sheaths and grounding system effects in power cable ampacity analysis.
Ali Zarghani, Pedram Dehgoshaei, Hossein Torkaman, Aghil Ghaheri,
Volume 20, Issue 1 (3-2024)
Abstract
Losses in electric machines produce heat and cause an efficiency drop. As a consequence of heat production, temperature rise will occur which imposes severe problems. Due to the dependence of electrical and mechanical performance on temperature, conducting thermal analysis for a special electric machine that has a compact configuration with poor heat dissipation capability is crucial. This paper aims to carry out the thermal analysis of an axial-field flux-switching permanent magnet (AFFSPM) machine for electric vehicle application. To fulfill this purpose, three-dimensional (3D) finite element analysis is performed to accurately derive electromagnetic losses in active components. Meanwhile, copper losses are calculated by analytic correlation in maximum allowable temperature. To improve thermal performance, cooling blades are inserted on the frame of AFFSPM, and 3D computational fluid dynamics (CFD) is developed to investigate thermal analysis. The effect of different housing materials, the external heat transfer coefficient, and various operating points on the components' temperature has been reported. Finally, 3-D FEA is used to conduct heat flow path and heat generation density.