Dielectric properties modeling and measurement of single tooth coil insulation system under accelerated degradation test

摘要

Degradation of electrical machines for traction purposes is important to understand for right-sizing traction system lifetime versus vehicle lifetime. Based on the proposed test specimen and predictive monitoring method, this paper is a continuation of [1] to present the dielectric properties changes, including the AC capacitance and DC leakage current or insulation resistance, during degradation test. This paper also proposes an analytical model to estimate the dielectric properties of a single tooth coil. The analytical model is verified against measurement. Comparing to the FEA model proposed in [1], the analytical model provides the convenience to perform sensitivity studies with geometrical property differences or physical property changes due to aging. Besides, the analytical model builds the link between the measured global properties and the average local dimensionless values, which are the volume resistivity and dielectric constant, which can be adapted by other simulations.