Novel stress grading systems for converter-fed motors

Wheeler, J.C.G.; Gully, A.M.; Baker, A.E.; Perrot, F.

doi:10.1109/mei.2007.288457

Cited by 16 publications

(5 citation statements)

References 1 publication

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“…In addition, the simplification from a 2D to a 1D modeling can be indeed useful, especially when non-axial-symmetric geometries need to be modeled in three dimensions. For example, form-wound coils can be modeled in 3D, when considering 2D elements in the stressgrading subdomains [49]. One problem that occurs with this simplification is that geometrical details like overlapping in multilayer systems are sometimes difficult to implement.…”

Section: Finite-element Dimension Reduction On the Stress-grading Coamentioning

confidence: 99%

Modeling and Simulation of Rotating Machine Windings Fed by High-Power Frequency Converters for Insulation Design

Cortés¹,

Gómez²,

KhalilHussain³

2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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Modern power systems include a considerable amount of power electronic converters related to the introduction of renewable energy sources, high-voltage direct current (HVDC) systems, adjustable speed drives, and so on. These components introduce repetitive pulses generated by the commutation of semiconductor switches, resulting in overvoltages with very steep fronts and high dielectric stresses. This phenomenon is one of the main causes of accelerated insulation aging of motors in power electronic-based systems. This chapter presents state-of-the-art computational tools for the analysis of motor windings excited by fast-front pulses related to the use of frequency converters based on pulsewidth modulation (PWM). These tools can be applied for the accurate prediction of overvoltages and dielectric stresses required to propose insulation design improvements. In the case of the stress-grading system used in medium-voltage (MV) motors, transient finite-element method (FEM) is used to study the effect of fast pulses. It is shown how, by controlling the material properties and the design of the stress-grading systems, solutions to reduce the adverse effects of fast pulses from PWM-type inverters can be proposed.

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Section: Finite-element Dimension Reduction On the Stress-grading Coamentioning

confidence: 99%

Modeling and Simulation of Rotating Machine Windings Fed by High-Power Frequency Converters for Insulation Design

Cortés¹,

Gómez²,

KhalilHussain³

2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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show abstract

“…In the field of practical commercial application, non-linear materials filled by traditional particles such as CB and SiC in the early stage have been applied in motor wire rods and cable accessories for a long time [12,13]. Scholars have verified the performance of electric field grading of traditional non-linear materials from long-term characteristics of ageing and temperature [14][15][16]. With the process of spraying and granulating ZnO microvaristors more maturely in recent years, ZnO composites characterised by stable non-linear properties have gradually become the alternatives to early products [17].…”

Section: Introductionmentioning

confidence: 99%

Self‐adaptive electrostatic discharge performance of ZnO microvaristors doped silicone rubber composites

Sun

Yuan

et al. 2023

High Voltage

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With the increase in applied voltage and the decrease in volume, integrated electronic modules have become electrostatic sensitive. ZnO microvaristors doped silicone rubber (SiR) composite, with electric field‐dependent conductivity, shows promising prospects for solving the electrostatic problem. In this study, 20 vol% to 50 vol% ZnO/SiR composite films, filled with 10–30 μm ZnO microvaristors, were prepared and put into the test of electrostatic discharge. Compared with the insulating and conducting materials, ZnO/SiR composites achieve the lowest initial voltage and a short time constant of electrostatic discharge. With the increase of ZnO microvaristors volume fraction, from 20% to 50%, the initial voltage and the time constant of electrostatic discharge drop from 1.78 to 0.72 kV and 3.1 ms to 0.4 μs. When the ZnO volume fraction is higher than 30%, there is no residual voltage after 0.1 s. To explore the reason behind different electrostatic discharge performances of the ZnO/SiR composites, the conductivities of the composites were measured. It is found that the break‐over voltage of the composite drops with the increase in the ZnO microvaristors volume fraction. When a high voltage impulse is applied on the ZnO/SiR film, the composite will turn to the conducting state and release the electrostatic charge adaptively so that the initial voltage can be controlled. This work supplies a novel electrostatic discharge idea for electric and electronic devices.

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“…The epoxy resin is designed to have non-linear conductivity property by filling an appropriate amount of semiconducting fillers, such as silicon carbide (SiC), into polymer matrix [3]. This type of composite is usually referred to as non-linear resistive field grading composite or stress grading composite and is very helpful to suppress the space charge accumulation and to homogenise the electric field distribution in equipment or components, such as motor end [4], GIS spacer [5] and bushing [6].…”

Section: Introductionmentioning

confidence: 99%

Enhanced switching electric field and breakdown strength of epoxy composites with core‐shell silicon carbide nanoparticles

et al. 2022

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Silicon carbide (SiC) is widely used to improve the non‐linear conductivity of non‐linear resistive field grading composite. In this paper, the SiC nanoparticles are modified into core‐shell nanoparticles with silica (SiO2) coating on the surface and are characterised by transmission electron microscopy and X‐ray diffraction, respectively. The 7 wt% SiC@SiO2/epoxy nanocomposite is then prepared, and the pure epoxy and 7 wt% SiC/epoxy nanocomposite are prepared as a contrast. The relative permittivity, thermally stimulated current, conductivity and breakdown strength are studied, respectively. The presence of SiO2 shell around SiC nanoparticles has a great effect on the relative permittivity and trap distribution. The epoxy nanocomposites show non‐linear conductivity characteristics, compared with pure epoxy. The 7 wt% SiC@SiO2/epoxy nanocomposite has higher switching electric field and breakdown strength than the 7 wt% SiC/epoxy nanocomposite, which is helpful for the application of non‐linear resistive field grading composite in higher‐voltage equipment or components.

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Novel stress grading systems for converter-fed motors

Cited by 16 publications

References 1 publication

Modeling and Simulation of Rotating Machine Windings Fed by High-Power Frequency Converters for Insulation Design

Modeling and Simulation of Rotating Machine Windings Fed by High-Power Frequency Converters for Insulation Design

Self‐adaptive electrostatic discharge performance of ZnO microvaristors doped silicone rubber composites

Enhanced switching electric field and breakdown strength of epoxy composites with core‐shell silicon carbide nanoparticles

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