Modeling of epoxy resin spacers for the 1 MV DC gas insulated line of ITER neutral beam injector system

Lorenzi, A. De; Grando, L.; Pesce, A.; Bettini, Paolo; Specogna, Ruben

doi:10.1109/tdei.2009.4784554

Cited by 86 publications

(38 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also the accurate evaluation of electrostatic force for the prediction of the mechanical behavior of electrostatic micro electro‐mechanical systems (MEMS) requires a number of accurate solutions for large‐scale three‐dimensional electrostatic boundary value problems (BVPs), see for example 17–19. The shape optimization of electromagnetic devices—high‐voltage insulators for gas‐insulated transmission lines 20, 21, just to give an example—or the imaging based on electrical capacitance tomography (ECT) require a considerable computational effort as well. In fact, in these applications, thousands of three‐dimensional electrostatic BVPs have to be solved, each time with a different geometry or different parameters of the materials.…”

Section: Introductionmentioning

confidence: 99%

“…The DGA has already been applied as an efficient numerical method to solve various classes of physical problems ranging from the already discussed electromagnetism to elasticity 44–47. In particular, to solve electrostatic problems, the formulation based on the electric scalar potential is widely used, see for example 18–21, 24, p. 49–53. However, it is known that a complementary electrostatic formulation based on a vector potential exists and that the simultaneous use of both formulations has the advantage of providing complementary energy bounds, which allows global quantities—such as capacitance or electrostatic force—to be obtained with high accuracy and minimum computational cost 48–52.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Complementary geometric formulations for electrostatics

Specogna

2010

Numerical Meth Engineering

View full text Add to dashboard Cite

The simultaneous use of a pair of complementary discrete formulations for electrostatic boundary value problems (BVPs) allows to accurately compute electromagnetic quantities, such as capacitance or electrostatic force with a minimum computational effort. In fact, the two formulations provide the upper and lower bounds for these quantities and their averages result quite close to the exact solution even for extremely coarse meshes. Despite the potential benefit to the many three-dimensional large-scale applications, taking advantage of this feature is not exploited in practice due to theoretical difficulties in the potential design. The aim of this paper is to fill this gap by rigorously introducing a pair of three-dimensional complementary geometric formulations to solve electrostatic BVPs on domains covered by conformal polyhedral meshes. In particular, an original formulation based on a vector potential is introduced by using cohomology theory with integer coefficients. It is shown how the so-called thick links are needed, which are representatives of the second cohomology group generators of the dielectric region. Two easy-to-implement graph-theoretic algorithms to automatically find such a basis with optimal computational complexity are described. Some benchmark problems are presented to show how the simultaneous use of both formulations yields to a sensible computational advantage. Therefore, solvers based on complementary formulations should be embedded in the next-generation of electromagnetic Computer-Aided Engineering (CAE) softwares

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Complementary geometric formulations for electrostatics

Specogna

2010

Numerical Meth Engineering

View full text Add to dashboard Cite

show abstract

“…These secondary electrons may accumulate on the insulator surface which further accelerates additional electron emissions that may lead to field distortion and ultimately result in surface flashovers. De Lorenzi et al [68,69] stated that the charge injection onto the surface may come from the current driven by the normal component of electric field, and/or from the gradient of the flowing current along the spacer surface, driven by the tangential component of the field. Dynamic unbalance between these two components may result in surface charge accumulation on insulator surface that ultimately may lead to surface flashover phenomena.…”

Section: Plasma-enhanced Treatmentmentioning

confidence: 99%

Surface fluorinated epoxy resin for high voltage DC application

Mohamad

Chen

Zhang

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

View full text Add to dashboard Cite

Charge build up under high voltage DC is a significant concern in the transmission system as its presence may distort the local electric field. By chemically treat polymeric insulation via directfluorination, and plasma enhanced fluorination process, the charge transport characteristics of the material can be modified. In doing so, excellent surface properties similar to those of fluoropolymers can be attained without compromising the bulk properties of the original polymeric insulation. The change in chemical components at the surface of polymeric insulation should lead to a corresponding change in dielectric properties at the surface and consequently may suppress the occurrences of charge build up. In this research, epoxy resin samples with various surface fluorinating conditions were formulated and treated. The samples then were characterised by SEM and EDX analysis, Raman spectroscopy, and DC surface conductivity measurements. To further explain the effects of fluorination treatment, modelling of the electric field and current density distribution had been carried out. Surface potential decay tests from corona discharge, as well as PEA measurements, show that there is a significant change in decay characteristics with the introduction of surface fluorinated layer. The decay mechanisms responsible for the observed

show abstract

“…Along with this downsizing trend, more consideration of the insulation characteristics for residual dc voltage due to, for example, switchgear operation is also required for GIS for ac systems. Furthermore, with dc power transmission technology drawing more and more attention on a global basis [1,2], it is becoming increasingly important to clarify the insulation characteristics of GIS for dc voltage [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Electric conductivity characteristics of FRP and epoxy insulators for GIS under DC voltage

Ueta

Okabe

Utsumi

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

View full text Add to dashboard Cite

Now that gas insulated switchgear (GIS) for ac systems is becoming increasingly compact as specifications are rationalized, more consideration of their insulation characteristics for residual dc voltage is required. Furthermore, with dc power transmission technology drawing more and more global attention, clarifying the insulation characteristics of GIS for dc voltage is increasingly important. The insulating portions for which the influence of dc voltage must be taken into consideration are solid insulators, such as insulating spacers. Under dc voltage, since the electric field distribution in an insulator differs from that under ac or impulse voltage and is governed by the resistance characteristics, clarifying its characteristics is crucial to study the GIS dc insulation design. As a solid insulator, focusing on fiber-reinforced plastics (FRP) used for GIS, for example, insulating rods, as well as partially treated epoxy resin; this paper experimentally investigated the bulk and surface electric conductivity under dc voltage, using the electric field, temperature, and other factors as parameters. As a result, the bulk electric conductivity of FRP in an edgewise direction exceeded that in the penetrating direction by one digit. It emerged that the electric conductivity of an insulating material with orientation like FRP varied depending on its direction. It was also found that, despite the fact the bulk and surface conductivity depended on the electric field for both FRP and epoxy resin, the variation width was relatively narrow within the range of the actual GIS operating electric field. The bulk and surface electric conductivity were also temperature-dependent, which meant the variation width was relatively wide. Furthermore, the surface electric conductivity was measured in SF 6 gas and in the air to investigate the influence of the ambient atmosphere, whereupon it emerged that the electric conductivity was higher in air due to the adherence of moisture. As mentioned above, the electric conductivity of an insulator varies due to various factors, such as the influence of the material orientation, electric field, temperature, and moisture. Consequently, the electric field distribution inside the insulator also changes, meaning these electric conductivity characteristics must be taken into consideration to study the GIS dc insulation characteristics.Index Terms -Gas insulated switchgear (GIS), dc voltage, insulator, fiber-reinforced plastic (FRP), epoxy, electric conductivity, SF 6 gas.

show abstract

Modeling of epoxy resin spacers for the 1 MV DC gas insulated line of ITER neutral beam injector system

Cited by 86 publications

References 18 publications

Complementary geometric formulations for electrostatics

Complementary geometric formulations for electrostatics

Surface fluorinated epoxy resin for high voltage DC application

Electric conductivity characteristics of FRP and epoxy insulators for GIS under DC voltage

Contact Info

Product

Resources

About