The influence of several environmental conditions on the partial discharge characteristics and on the lifetime of magnet wires under inverter pulse operation

Busch, Rudolf; Pohlmann, Friedhelm; Müller, Kai

doi:10.1109/iseim.2001.973755

Cited by 11 publications

(5 citation statements)

References 1 publication

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“…The electric field E SC , which decreases the field in the air gap after each discharge, takes the same direction as the external field, reinforcing it, at each voltage inversion. In this picture, the transition from positive to negative peak (peak-to-peak electric field) is the premise for a PD occurrence, as observed also in [120].…”

Section: Space Charge Formation In Insulationmentioning

confidence: 75%

Bringing an insulation to failure: the role of space charge

Montanari

2011

IEEE Trans. Dielect. Electr. Insul.

268

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Considering the title of this paper, one might think that everything has been said, shown, proven and discussed already on ageing and failure of electrical insulating materials, based on at least half century of research work and field feedbacks. However, perhaps there is still room to collect ideas and speculate on apparently proven or brand new concepts, such as the interrelation between ageing mechanisms and physically measurable quantities such as space charge, partial discharges and conduction current. The latter is, indeed, the scope of this paper, which is taken from the Whitehead Memorial Lecture given at the 2010 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP). On one hand we will revisit the concepts of space charge accumulation in insulating (polymeric) materials, considering also the latest achievements which deal with ultra-fast charge pulses (solitons), on the other hand we will discuss how space charge can contribute to ageing rate under dc, ac or impulsive voltage, directly through electric field alteration, or indirectly modifying a fundamental ageing factor such as partial discharges.The goal is, at the very end, to show how much such basic investigations can have a fundamental impact on insulation design and electrical apparatus long-term performance/ reliability. Index Terms -Space charge,degradation, charge packets,aging models, partial discharges, insulation breakdown. 2 2 4 ,where J ii is the impact ionization rate, I is the ionization energy, J DEA is the Dissociative Electron Attachment Gian Carlo Montanari (M'87-SM'90-F'00) was born on 8 November 1955. In 1979, he took the Master degree in electrical engineering at the University of Bologna. He is currently Full Professor of Electrical Technology at the Department of Electrical Engineering of the University of Bologna, and teaches courses of Technology and Reliability. He has worked since 1979 in the field of aging and endurance of solid insulating materials and systems, of diagnostics of electrical systems and innovative electrical materials (magnetics, nanomaterials, electrets, superconductors). He has been also engaged in the fields of power quality and energy market, power electronics, reliability and statistics of electrical systems. He is a member of AEI and Institute of Physics. He is a member of the AdCom of the IEEE DEIS. Since

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Section: Space Charge Formation In Insulationmentioning

confidence: 75%

Bringing an insulation to failure: the role of space charge

Montanari

2011

IEEE Trans. Dielect. Electr. Insul.

268

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“…In literature, numerous studies investigate the correlation between ambient factors (i.e., humidity, pressure, ambient temperature, etc.) and PDIV [81][82][83][84][85][86]. Considering EMs for MEA, the low-pressure conditions decrease PDIV value [12,13,83], and severe electrical aging is observed in corona-resistant wires [87,88].…”

Section: Ambient Stressmentioning

confidence: 99%

Insulation for Rotating Low-Voltage Electrical Machines: Degradation, Lifetime Modeling, and Accelerated Aging Tests

Zhou,

Giangrande,

et al. 2024

Energies

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The low-voltage electric machine (EM) is a core technology for transportation electrification, and features like high power density and compact volume are essential prerequisites. However, these requirements are usually in conflict with the reliability property of EM, especially in the safety-critical industry such as aviation. Therefore, an appropriate balance between high-performance and reliability needs to be found. Often, the over-engineering method is applied to ensure safety, although it might have a detrimental effect on the EM volume. To address this issue, the EM reliability assessment is included at the EM design stage through the physics of failure (PoF) theory. In EMs, the windings play a key role in electromechanical energy conversion, but their insulation system is subject to frequent failure and represents a reliability bottleneck. Therefore, in-depth research on the root causes of insulation breakdown is beneficial for EM reliability improvement purposes. Indeed, increasing awareness and knowledge on the mechanism of the insulation degradation process and the related lifetime modeling enables the growth of appropriate tools for achieving reliability targets since the first EM design steps. In this work, the main aspects of the insulation system, in terms of materials and manufacturing, are first reviewed. Then, the principal stresses experienced by the winding insulation system are deeply discussed with the purpose of building a profound understanding of the PoF. Finally, an overview of the most common insulation lifetime prediction models is presented, and their use for accomplishing the reliability-oriented design (RoD) and the remaining useful life (RUL) estimation are examined.

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“…Therefore, twisted pairs are chosen for the investigation. Such a configuration of specimens for studying humidity impact on PD is preferred referring to the literature [19][20][21]. In this paper, the enamelled magnet wires with the main properties listed in Table 1 are twisted following the IEC standard [22], as shown in Figure 2.…”

Section: Specimen Preparationmentioning

confidence: 99%

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

Giangrande

Zhao

et al. 2022

IET Science Measure & Tech

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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).

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The influence of several environmental conditions on the partial discharge characteristics and on the lifetime of magnet wires under inverter pulse operation

Cited by 11 publications

References 1 publication

Bringing an insulation to failure: the role of space charge

Bringing an insulation to failure: the role of space charge

Insulation for Rotating Low-Voltage Electrical Machines: Degradation, Lifetime Modeling, and Accelerated Aging Tests

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

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