Electrical Properties of Different Polymeric Materials and their Applications: The Influence of Electric Field

Haque, Sk Manirul; Rey, Jorge Alfredo Ardila; AbubakarMasúd, Abdullahi; Umar, Yunusa

doi:10.5772/67091

Cited by 23 publications

(19 citation statements)

References 49 publications

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“…To relieve this high field stress region, a layer for coating the metallization edges was considered in three cases with polyimide layer ( ε r = 3.5), a high permittivity ( ε r = 40) layer of a polymer/ceramic composite and ZnO microvaristor layer described above. A comprehensive study of the general structure of polymers, their properties and applications can be found in [49]. For polyimide layer, E max in the layer (adjacent to the protrusion) and gel will be 2.3 × 108 and 0.18 × 108 V/m, respectively [48].…”

Section: Linear Resistive Electric Field Controlmentioning

confidence: 99%

Electrical Insulation Weaknesses in Wide Bandgap Devices

Ghassemi¹

2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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The power electronics research community is balancing on the edge of a game-changing technological innovation: as traditionally silicon (Si) based power semiconductors approach their material limitations, next-generation wide bandgap (WBG) power semiconductors are poised to overtake them. Promising WBG materials are silicon carbide (SiC), gallium nitride (GaN), diamond (C), gallium oxide (Ga 2 O 3 ) and aluminum nitride (AlN). They can operate at higher voltages, temperatures, and switching frequencies with greater efficiencies compared to existing Si, in power electronics. These characteristics can reduce energy consumption, which is critical for national economic, health, and security interests. However, increased voltage blocking capability and trend toward more compact packaging technology for high-power density WBG devices can enhance the local electric field that may become large enough to raise partial discharges (PDs) within the module. High activity of PDs damages the insulating silicone gel, lead to electrical insulation failure and reduce the reliability of the module. Among WBG devices, electrical insulation weaknesses in WBG-based Insulated Gate Bipolar Transistor (IGBT) have been more investigated. The chapter deals with (a) current standards for evaluation of the insulation systems of power electronics modules, (b) simulation and modeling of the electric field stress inside modules, (c) diagnostic tests on modules, and (d) PD control methods in modules.

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Section: Linear Resistive Electric Field Controlmentioning

confidence: 99%

Electrical Insulation Weaknesses in Wide Bandgap Devices

Ghassemi¹

2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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“…In terms of selection of insulation materials, modified epoxy mica tape with continuous insulation is usually used as the basic material for large generators [27]. Its resistivity is 2 × 10 14 Ω·m and the relative dielectric constant is 4.…”

Section: Model Of the Three-dimensional At The End Of A Stator Barmentioning

confidence: 99%

“…The distribution of the electric field when the corona layer is linear is shown in Figure 4. As shown in the figure, the electric field distribution is concentrated only at the notch and has a value of In terms of selection of insulation materials, modified epoxy mica tape with continuous insulation is usually used as the basic material for large generators [27]. Its resistivity is 2 × 10 14 Ω·m and the relative dielectric constant is 4.…”

Section: Influence Of Nonlinear Corona Protection Materials On the Dismentioning

confidence: 99%

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Zhang

et al. 2018

Energies

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The electric field distribution at the end of a large hydro-generator is highly nonuniform and prone to corona discharge, which damages the main insulation and significantly reduces the service life of the hydro-generator. In order to reduce the thickness of the main insulation and the physical size of a large hydro-generator, it is necessary to understand the distribution of the electric field at the end of its stator bar. In this paper, the stator bar at the end of a large generator is simulated using the finite element method to determine the distribution of the potential, electric field, and loss at the rated voltage, as well as to elucidate the differences between the linear corona protection, two-segment nonlinear corona protection, and three-segment nonlinear corona protection structures. The influences of the arc angle, length of each corona protection layer, intrinsic resistivity of the corona protection material, and nonlinear coefficient are also analyzed. The results manifest that the angle of the stator bar should be 22.5 • , the difference in resistivity between the two adjacent corona protection coatings should not exceed two orders of magnitude, and the resistivity of the medium resistivity layer should be nearly 10 6 Ω·m or 10 7 Ω·m, for an optimal design of the corona protection structure.

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“…where, substituting x to a, being a ≪ b, it is evident that the maximum value of the electric field occurs on the surface of the internal electrode. This maximum field value is given by [22]:…”

Section: Capacitive Analytical Modeling For Power Quality Sensormentioning

confidence: 99%

Simulation and Optimization of Electrical Insulation in Power Quality Monitoring Sensors Applied in the Medium-Voltage

Santos¹,

Peres²,

Cano³

et al. 2018

Simulation and Modelling of Electrical Insulation Weaknesses in Electrical Equipment

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Thanks to the Smart Grid initiative, the focus for medium-voltage MV (13.8-34 kV) smart meters leveraged the development of sensors for distribution application. In order to be useful at power quality monitoring, the sensors needs to attend, at least, the International Electrotechnical Commission (IEC) 61000-4-30 and IEC 61000-4-7 standards with highaccuracy in terms of voltage (less than 0.1%), current (less than 1.0%) and measuring the waveform distortion data up to the 50th harmonic of 50 or 60 Hz alternating frequency. This kind of sensor is built with two capacitors connected in series. The first capacitor is a commercial electronic low-voltage device. One terminal of this capacitor is connected to the medium-voltage (MV) conductor. The second one, is connected to the other capacitor that is constructed using the own sensor packaging. This second capacitor has an electrode, that is connected with the first capacitor and the other terminal is connected to the ground. The voltage is measured between the terminals of the low voltage capacitor. The performance of this capacitor depends on the geometry and the materials used in the electrical insulation. This chapter describes the simulations and modeling of the capacitor electrodes using a finite-elements software, COMSOL Multiphysics, for modeling in order to optimize the performance of sensor in terms of electric field distribution.

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Electrical Properties of Different Polymeric Materials and their Applications: The Influence of Electric Field

Cited by 23 publications

References 49 publications

Electrical Insulation Weaknesses in Wide Bandgap Devices

Electrical Insulation Weaknesses in Wide Bandgap Devices

Optimization of the Electric Field Distribution at the End of the Stator in a Large Generator

Simulation and Optimization of Electrical Insulation in Power Quality Monitoring Sensors Applied in the Medium-Voltage

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