Progress in development of a nanocomposite stator winding insulation system for improved generator performance

Hildinger, Thomas; Weidner, J.-O.

doi:10.1109/eic.2017.8004655

Cited by 19 publications

(4 citation statements)

References 3 publications

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“…The results show that the power density of the motor has been improved by 10∼15% through adopting SiO 2nanocomposite. Also, the insulation lifetime can be increased since SiO2 acts as a barrier to obstruct breakdown channels created by PD [96]. Simulation techniques can be used to effectively predict the distribution of nanofillers as well as the mechanical strength of nanocomposite resin base on stress-strain curve (S-S curve).…”

Section: Section V Polymer Nanocompositementioning

confidence: 99%

Survey of Insulation Systems in Electrical Machines

Hemmati

El-Refaie

2019

2019 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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Insulating materials and insulation systems design have been gaining more attentions as more electrical machines tend to operate in harsher environments for various applications. Harsh environments include high temperature, humidity, erosion, low air pressure, etc. This paper discusses recent advances in insulation systems for electrical machines. Insulation tests as well as test standards that have been used to evaluate insulation systems and detect insulation failures will be discussed. Insulating materials used for a wide range of industrial applications such as wind turbine generators, aerospace hybrid/electric powertrain, and hydro generators have been summarized. For the emerging high-altitude, highvoltage aerospace applications, partial discharge and its impact on insulation systems will be discussed. Finally, polymer nanocomposite materials with excellent thermal conductivity and dielectric strength are highlighted as an outlook. SECTION I. Introduction Due to the continued growth of renewable energys, the number of electrical machines used worldwide has significantly increased. Insulation system is a very critical component of electrical machines. Insulation breakdown can lead to failures, which eventually result unpredicted downtime and negative financial impacts and in some applications can be a safety hazard. For some specific industries where uninterruptible operation is required, the unpredicted downtime is unacceptable. The unpredicted downtime for an offshore oil plant would be $25,000/h [1]. The dielectric strength of electrical insulation materials has been gradually improved over the years. By introducing new materials in the past 20 years for instance, the dielectric strength of ground-wall insulation nearly doubled [2]. Electrical, mechanical, thermal, and ambient stresses can cause insulation degradation which consequently leads to insulation failure [3], [4]. Insulation failure causes short circuits in the stator winding and consequently high currents could pass through the defected stator winding [5]. A survey on 1141 induction motors with power ratings above 200 hp shows that around 30% of motor failures are due to insulation failures [6]. With advances in sensors, digital signal processing, diagnosis methods and test standards, insulation failures can be detected [7], [8]. Through online estimation of material degradation and lifetime in early stages, insulation systems of electric machines can be protected from further aging while unpredicted downtime could be avoided through scheduled maintenance. Even though insulation system is a passive component in an electrical machine which does not produce torque, insulation build/thickness (which represents the key thermal resistance in electrical machine)can have significant impact on the machine cooling and hence electrical loading and torque production. There have been several efforts to minimize insulation thickness for design compactness, low manufacturing cost and high efficiency [3]. The two main functions of insulation systems in electr...

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Section: Section V Polymer Nanocompositementioning

confidence: 99%

Survey of Insulation Systems in Electrical Machines

Hemmati

El-Refaie

2019

2019 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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“…The addition of nanoscale fillers to polymer dielectrics to create nanodielectrics results in materials with significantly improved dielectric breakdown strength, permittivity, and loss properties. For example, nanofillers can increase the effective dielectric permittivity without compromising, or in some cases even enhancing, the breakdown strength. , Nanodielectrics are thus promising materials for applications in high voltage cable transmission, storage application, and solid state electronics. , The enhancement in properties depends critically on the properties and volume of the interfacial region: a nanosized region surrounding the filler with properties different from both the particle and the matrix. It is thus imperative for materials design and control that the properties of the interfacial region be known and the impact of the nanofiller surface chemistry on those properties understood.…”

Section: Introductionmentioning

confidence: 99%

“… 1 , 2 Nanodielectrics are thus promising materials for applications in high voltage cable transmission, storage application, and solid state electronics. 3 , 4 The enhancement in properties depends critically on the properties and volume of the interfacial region: 5 a nanosized region surrounding the filler with properties different from both the particle and the matrix. It is thus imperative for materials design and control that the properties of the interfacial region be known and the impact of the nanofiller surface chemistry on those properties understood.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Properties of Polymer Nanocomposite Interphases Using Electrostatic Force Microscopy and Machine Learning

Gupta

Ruzicka

Benicewicz

et al. 2023

ACS Appl. Electron. Mater.

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Knowing the dielectric properties of the interfacial region in polymer nanocomposites is critical to predicting and controlling dielectric properties. They are, however, difficult to characterize due to their nanoscale dimensions. Electrostatic force microscopy (EFM) provides a pathway to local dielectric property measurements, but extracting local dielectric permittivity in complex interphase geometries from EFM measurements remains a challenge. This paper demonstrates a combined EFM and machine learning (ML) approach to measuring interfacial permittivity in 50 nm silica particles in a PMMA matrix. We show that ML models trained to finite-element simulations of the electric field profile between the EFM tip and nanocomposite surface can accurately determine the interface permittivity of functionalized nanoparticles. It was found that for the particles with a polyaniline brush layer, the interfacial region was detectable (extrinsic interface). For bare silica particles, the intrinsic interface was detectable only in terms of having a slightly higher or lower permittivity. This approach fully accounts for the complex interplay of filler, matrix, and interface permittivity on the force gradients measured in EFM that are missed by previous semianalytic approaches, providing a pathway to quantify and design nanoscale interface dielectric properties in nanodielectric materials.

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“…Nanocomposites are considered to have a potential to revolutionize the insulation structure design of rotating machines as well as high voltage apparatus. Hildinger et al have stated that the incorporation of SiO 2 nanofillers in epoxy-mica insulation have resulted in a highly efficient stator winding insulation, which has improved specific power output without reduction on insulation lifetime [9]. Due to their high dielectric constant, excellent stiffness, superior mechanical strength, and high corrosion resistance, glass fiber reinforced polymer nanocomposites are considered as promising insulating materials in power apparatus, along with automotive, aerospace, wind energy harvesting, and marine applications [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Electrical and Thermal Performance of Glass Fiber Reinforced Epoxy–MgO Nanocomposites

Naveen¹,

Babu²,

Sarathi³

et al. 2021

Energies

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Epoxy nanocomposites reinforced with glass fiber, have been prepared with various weight percentages (1, 3, and 5 wt.%) of MgO nanofillers to improve their electrical and thermal performance. An increase in MgO nanofiller content up to 3 wt.% tends to enhance surface discharge and corona inception voltages measured using fluorescence and UHF methods, under both AC and DC voltage profiles. Reduced initial surface potential along with increased decay rate is observed after inclusion of MgO nanoparticles. Before and after the polarity reversal phenomena, heterocharge formation is observed in the bulk of test specimens. In comparison with other test samples, the 3 wt.% sample had reflected lower electric field enhancement factor. After MgO filler was added to glass fiber reinforced polymer (GFRP) composites, the coefficient of thermal expansion (CTE) has reduced, with the 3 wt.% specimen having the lowest CTE value. TGA measurements revealed an improvement in thermal stability of the GFRP nanocomposites up on the inclusion of MgO nanofillers. Overall, the GFRP nanocomposite sample filled with 3 wt.% nano-MgO outperformed the other test samples in terms of electrical and thermal performance.

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Progress in development of a nanocomposite stator winding insulation system for improved generator performance

Cited by 19 publications

References 3 publications

Survey of Insulation Systems in Electrical Machines

Survey of Insulation Systems in Electrical Machines

Dielectric Properties of Polymer Nanocomposite Interphases Using Electrostatic Force Microscopy and Machine Learning

Investigation on Electrical and Thermal Performance of Glass Fiber Reinforced Epoxy–MgO Nanocomposites

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