Temperature Impact on PDIV for Turn-to-Turn Insulation of Inverter-Fed Motors: From Ground Level to Cruising Altitude

Considering the turn-to-turn insulation as the most susceptible part to the failure of the electrical machine's insulation system in inverter-fed motors, this article aims to elucidate the effect of temperature $\mathrm {({T})}$ on the streamer inception parameters (SIPs), including the Schumann constant $\mathrm {({K})}$ , critical field line length (CFLL), air effective ionization coefficient ( $\alpha _{\text {eff}}$ ), and streamer inception field ( ${E}_{\text {inc}}$ ). Particular attention is also given to extending the partial discharge inception voltage (PDIV) modeling at cruising altitude (CA), equivalent to the air pressure of 200 mbar, as a function of ${T}$ based on the Schumann's streamer inception criterion (SCSIC), compared with the results obtained at 1000 mbar, i.e., ground level (GL). Furthermore, the ratios of SIPs and PDIV values at CA to those attained at GL are analyzed as a function of ${T}$ . The investigation findings serve as a prescription for electrical machine designers to enhance the insulating design of electrical machines used in more electric aircraft (MEA) applications.