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Your search keyword '"Giangrande, Paolo"' showing total 251 results
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251 results on '"Giangrande, Paolo"'

1. Effect of Environmental and Operating Conditions on Partial Discharge Activity in Electrical Machine Insulation: A Comprehensive Review.

Author

Ji, Yatai, Giangrande, Paolo, and Zhao, Weiduo

Subjects
*ELECTRIC insulators & insulation, *PARTIAL pressure, *CONFORMANCE testing, *PHYSICS, *HUMIDITY, *PARTIAL discharges
Abstract

Electrical machines for transportation applications are subjected to harsh environmental conditions during their operations. Partial discharge (PD), which is one of the main reasons for insulation failure, is greatly affected by ambient conditions (i.e., temperature, pressure, and humidity). Countless efforts are made for a comprehensive understanding of the physics of PD under variable environmental factors. This paper aims to review recent works addressing temperature, pressure, and humidity impact on PD activity. The main content of the paper is organized into three sections dealing with each environmental factor. In every section, relevant publications are reviewed considering the type of samples tested, voltage waveform applied, mutual effects, and the most common PD modeling strategies used. The applicability of the PD measurements for PD risk assessment is also discussed. Based on the review, the current progress in understanding the environmental effects on the PD inception mechanism and PD characteristics is presented and discussed in detail, and future research trends in this field are outlined. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Air Pressure Impact on the Avalanche Size for Turn-to-Turn Insulation of Inverter-Fed Motors

Author

Naderiallaf, Hadi, Ji, Yatai, Giangrande, Paolo, and Galea, Michael

Abstract

This article endeavors 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 partial discharge inception voltage (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 ( ${N} _{\text {c}}$ ) increase with air pressure reduction. Different SIPs such as critical field line length (CFLL), effective ionization coefficient of air ( $\alpha _{\text {eff}}$ ), PD inception field ( ${E} _{\text {inc}}$ ), firing voltage ( ${V} _{\text {firing}}$ ) across the critical field line (CFL), and ${K}$ and ${N} _{\text {c}}$ are analyzed 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 to improve the insulation design of electrical machines employed in the more electric aircraft (MEA) applications.

Published
2024
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7. Design and Testing of Disconnection Actuators for Enhancing Safety and Preventing Failure Escalation.

Author

Akcay, Yusuf, Tweedy, Oliver, Giangrande, Paolo, and Galea, Michael

Subjects
SYSTEM failures, ELECTROMAGNETIC devices, ACTUATORS, TEST design, FINITE element method
Abstract

The growing demand for reliability has led to an increased interest in developing effective disconnection systems for enhancing the safety of and preventing failure escalation in engineering systems. Considering this prospect, the design optimization of two disconnection actuators composed of a coaxial magnetic coupling linked to an electromagnetic device is presented and discussed. The disconnection actuator delivers a contactless torque transmission through the coaxial magnetic coupling, whereas the torque transfer is interrupted by the electromagnetic device in case a failure is detected via a dedicated algorithm. The performed design procedure relies on 2D finite element analysis, and trade-off studies are carried out to achieve an optimized geometry of an electromagnetic device. Finally, two disconnection actuators, for high-speed and high-torque applications, are prototyped and tested, with the aim of evaluating their disconnection capability. For both disconnection actuators, the developed force and voltage–current characteristics are measured along with the disconnection time. [ABSTRACT FROM AUTHOR]

Published
2023
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13. Temperature Impact on PDIV for Turn-to-Turn Insulation of Inverter-Fed Motors: From Ground Level to Cruising Altitude

Author

Naderiallaf, Hadi, Ji, Yatai, Giangrande, Paolo, and Galea, Michael

Abstract

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.

Published
2024
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25. System Level Reliability Assessment of Short Duty Electric Drives for Aerospace

Author

Madonna, Vincenzo, Giangrande, Paolo, Harikumaran, Jayakrishnan, Buticchi, Giampaolo, and Galea, Michael

Subjects
Reliability, Insulation, Stress, Aircraft, Windings, Transportation, Multichip modules
Abstract

The reliability performance of electrical machines and power electronics converters are generally verified separately, even if the two components are meant to be part of the same electric drive. Depending on the application, however, it might be necessary that the whole drive fulfils a certain reliability target, which is pre-defined by the application itself. An appropriate design approach should involve joint efforts between machine and converter designers, so that the final product is as optimized as possible, while still satisfying reliability constraints. In this work, a system level reliability study for short duty electric drives is proposed and implemented, using an aerospace electromechanical actuator as case-study. Concepts of statistical post-processing for the lifetime prediction of power modules are discussed throughout. Additionally, accelerated lifetime tests on electrical machine windings are performed for predicting the motor insulation’s time to failure. For the short duty aerospace drive under investigation, i.e. case-study, it is finally verified that the power electronics converter represents the reliability bottleneck.

Published
2021

26. Investigation on combined effect of humidity–temperature on partial discharge through dielectric performance evaluation.

Author

Ji, Yatai, Giangrande, Paolo, Zhao, Weiduo, Madonna, Vincenzo, Zhang, He, Li, Jing, and Galea, Michael

Subjects
*HUMIDITY, *PARTIAL discharges, *DIELECTRICS, *FINITE element method, *PHOTOMULTIPLIERS
Abstract

The humidity role in the partial discharge (PD) inception mechanism is quite challenging, especially when considering the environmental temperature. Indeed, there is no general rule to explain the humidity effect on the PD phenomenon. In this paper, the PD activity in inter‐turn insulation is experimentally investigated for different relative humidity (RH) conditions at three different ambient temperatures, that is, 30°C, 60°C, and 90°C. Partial discharge inception voltage (PDIV) is directly measured through a photomultiplier tube (PMT), whereas the tip‐up tests are performed aiming at monitoring both dissipation factor (tanδ) and insulation capacitance (IC). These extra measurements (diagnostic dielectric markers) allow better assessing the insulation status. The adoption of the tip‐up test enables the insulation properties measurement. Based on the tip‐up tests' findings, the interfacial polarization process starts at 75% RH under 60°C, while the high conductivity area is already formed at 75% RH when the ambient temperature is 90°C. The water film formation deduced from the tip‐up test is then used to explain the trend of PDIV, and the validity is further proved by finite element analysis (FEA). [ABSTRACT FROM AUTHOR]

Published
2023
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