Air Pressure Impact on the Avalanche Size for Turn-to-Turn Insulation of Inverter-Fed Motors

Naderiallaf, H.; Ji, Y.; Giangrande, P.; Galea, M.

Abstract

This paper endeavours to illuminate the variations of various streamer inception parameters (SIPs) with respect to air pressure based on Schumann’s streamer inception criterion (SCSIC). The results based on measured PDIV values and using electric field distribution obtained via electrostatic simulations and ionization swarm parameters reveal that the Schumann constant, K , which is the natural logarithm of the threshold number of electrons determining the transition from Townsend to streamer discharge, and consequently, the critical avalanche size ( N c ) increase with air pressure reduction. Different SIPs such as critical field line length (CFLL), effective ionization coefficient of air (α eff ), PD inception field ( E inc ), firing voltage ( V firing ) across the critical field line (CFL), K and N c are analysed extensively as a function of air pressure. In light of the findings of this contribution, it is demonstrated that the derived K functions as a function of air pressure can improve drastically the accuracy of PDIV prediction in particular for low air pressures rather than a single K parameter value obtained at ground level. The study’s findings represent a guideline for electrical machine designers for improving the insulation design of electrical machines employed in the More Electric Aircraft (MEA) applications.

Citation

Naderiallaf, H., Ji, Y., Giangrande, P., & Galea, M. (2024). Air Pressure Impact on the Avalanche Size for Turn-to-Turn Insulation of Inverter-Fed Motors. IEEE Transactions on Dielectrics and Electrical Insulation, 31(1), 85-94. https://doi.org/10.1109/TDEI.2023.3324287

• Journal Article Type: Article
• Acceptance Date: Oct 9, 2023
• Online Publication Date: Oct 12, 2023
• Publication Date: 2024-02
• Deposit Date: Oct 13, 2023
• Publicly Available Date: Oct 16, 2023
• Journal: IEEE Transactions on Dielectrics and Electrical Insulation
• Print ISSN: 1070-9878
• Electronic ISSN: 1558-4135
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 31
• Issue: 1
• Pages: 85-94
• DOI: https://doi.org/10.1109/TDEI.2023.3324287
• Keywords: Insulation , Partial discharges , Discharges (electric) , Electric fields , Ionization , Atmospheric modeling , Wires, Air pressure , avalanche breakdown , electric machines , finite element analysis , insulation , partial discharges , reliability
• Public URL: https://nottingham-repository.worktribe.com/output/25956503
• Publisher URL: https://ieeexplore.ieee.org/document/10283872