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Øystein Hestad

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Øystein Hestad

Forsker

Øystein Hestad
Telefon: 971 12 257
Mobil: 971 12 257
Avdeling: Elkraftteknologi
Kontorsted: Trondheim

Publikasjoner og ansvarsområder

Publikasjoner

Publikasjon

Photoionization Model for the Transition to Fast Mode Streamers in Dielectric Liquids

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1399267

The transition to fast mode streamers is explained through a model that includes a photoionization mechanism. The model assumes that photons are created in the head of the streamer, and that the photoionization cross section is dependent on the electric field through field dependent ionization poten...

Forfattere Madshaven Inge Smalø Hans Sverre Unge Michael Hestad Øystein Leif Gurandsrud
År 2016
Type Del av bok/rapport
Publikasjon

Thermal Decomposition of Cyclohexane by Kinetic Monte Carlo Simulations and its Relevance to Streamer Formation

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1399249

Kinetic Monte Carlo was used to simulate the decomposition of cyclohexane at temperatures up to 10 000 K. Rate constants needed for the simulations were obtained from literature and combined with differences in Gibbs free energy between the reactants and products. The degree of decomposition and an ...

Forfattere Hestad Øystein Leif Gurandsrud Vuong Au-Dung Madshaven Inge Åstrand Per-Olof Harald
År 2016
Type Del av bok/rapport
Publikasjon

Conductivity and permittivity of Midel 7131 : effect of temperature, moisture content, hydrostatic pressure and electric field

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1394037

Knowledge of the conductivity and permittivity of materials used in subsea connectors is needed to predict the electric field distribution in the connectors. The synthetic ester Midel 7131, being one of several dielectric liquids used in subsea connectors, has been chosen as a relevant candidate mat...

Forfattere Aakre Torstein Grav Ve Torbjørn Hestad Øystein
År 2016
Type Tidsskriftspublikasjon
Publikasjon

The effect of temperature cycling on mechanical and electrical properties of syndiotactic polypropylene

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1375207

Polypropylenes (PP) are a candidate to replace cross-linked polyethylene (XLPE) in medium voltage cables. This is due to its recyclability and potentially lower energy consumption during production. To prove to be an alternative, the PPs must meet the same requirements as for XLPE. The maximum servi...

Forfattere Aakre Torstein Grav Hestad Øystein Hølto Jorunn Hvidsten Sverre
År 2016
Type Del av bok/rapport
Publikasjon

Self-healing composites for high voltage electrical insulation

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1258142

A self-healing electrical insulation material for high voltage apparatuses has yet not been developed. Such a material would have been very attractive for electrical components installed in conditions were service failures cause time consuming and very expensive replacements. This paper reports resu...

År 2016
Type Del av bok/rapport
Publikasjon

Effect of static mechanical strain on the DC conductivity of extruded cross-linked polyethylene cable insulation

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1258129

DC current measurements were performed on a medium voltage XLPE cable at voltages from 8.5 to 65 kV (average field from 2.5 to 19 kV/mm). To assess the effect of mechanical strain on the conductivity of the insulation, the cable was wrapped around a tube with an outer diameter of 110 mm (max strain ...

Forfattere Hestad Øystein Leif Enoksen Henrik Hvidsten Sverre
År 2016
Type Del av bok/rapport
Publikasjon

Numerical simulation of positive streamer propagation in cyclohexane

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1162812

A numerical 3D simulation of positive streamer propagation in a liquid, using cyclohexane as a reference case, in a needle-plane geometry is presented. The physical basis of this model is a version of the Townsend-Meek streamer criteria, known from gas discharges, adapted to a liquid containing an a...

Forfattere Hestad Øystein Leif Grav Torstein Lundgaard Lars Esben Ingebrigtsen Stian Unge M. Hjortstam O.
År 2014
Type Del av bok/rapport
Publikasjon

Self-healing high voltage electrical insulation materials

https://www.sintef.no/publikasjoner/publikasjon/?pubid=CRIStin+1142937

Electrical treeing can be the precursor to catastrophic failure for electrical insulation materials and hence significantly shorten their service lifetime. Considering that damage inside the composites (thermoset insulation materials containing fillers) is difficult to detect and particularly to rep...

År 2014
Type Del av bok/rapport
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