Browsing NTNU Open by Author "Hvidsten, Sverre"
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A stochastic model for contact surfaces at polymer interfaces subjected to an electrical field
Kantar, Emre; Hvidsten, Sverre; Mauseth, Frank; Ildstad, Erling (Journal article; Peer reviewed, 2018)Morphology of the contact area between solid insulation materials ultimately determines the short- and long-term electrical properties of the complete insulation system. The main purpose of this paper is to propose a ... -
Characterization of Insulation Materials for HVDC Subsea Connectors - Evaluation of Measurement Methods for Surface Conductivity
Jacobsen, Brynjar Aalberg (Master thesis, 2015)The focus of this work has been on characterization methods for the surface conductivity of insulation materials in HVDC subsea connectors. Having a proper characterization is important when selecting the most suited design ... -
Comparison of Offline VLF PD Measurements and Online PD Measurements on a 50-Year-Old Hydrogenerator Stator in Norway
Eberg, Espen; Aakre, Torstein Grav; Berg, Gunnar; Hvidsten, Sverre (Chapter, 2018)Stator winding insulation is the part of the hydrogenerator experiencing the highest number and the most damaging failures. Partial discharge (PD) measurement, both offline and online, are commonly used for condition ... -
Condition Assessment of Hydrogenerator Stator Bar Insulation Using Partial Discharge Measurements
Aakre, Torstein Grav; Ildstad, Erling; Hvidsten, Sverre (Chapter, 2018)This paper presents results from laboratory measurements of partial discharge (PD) activity in 50 cm long samples cut from the mainwall section of old hydrogenerator stator bars. All stator bars were manufactured in 1976 ... -
Condition Assessment of Medium Voltage Cable Accessories - PD Measurements at Variable Frequencies
Einan, Gunnar Stokke (Master thesis, 2016)Diagnostic PD testing of medium voltage cables can be performed at very low frequencies (VLF, 0.1 Hz), to reduce capacitive currents. At 0.1 Hz the field distribution in the field grading materials is likely different from ... -
Condition Assessment of Medium Voltage Cable Joints - Dielectric Spectroscopy of Field Grading Materials
Abil, Biran (Master thesis, 2017)The electrical properties of a widely used stress control tube for medium voltage heat-shrink joints are examined in this master thesis by using non-destructive laboratory methods. They were determined by use of time domain ... -
Condition Assessment of Medium Voltage Cable Joints - Dielectric Spectroscopy of field grading materials
Sanden, Mai-Linn (Master thesis, 2015)This thesis examines the electrical properties of a commonly used stress control tube for medium voltage heat-shrink joints using non-destructive methods in laboratory. The electrical properties of the tube were determined ... -
Condition Assessment of Service Aged Medium Voltage Cable Joints During Load Cycling
Bjurholt, Ingeborg (Master thesis, 2018)In order to be able to take maximum advantage of the remaining lifetime of the components in the distribution network, utilities need to know the condition of the equipment as accurately as possible. When partial discharges ... -
Condition Assessment of Wind Farm Medium Voltage Cable Joints
Halvorson, Hans Lavoll (Master thesis, 2012)Rapid aging and failure in wind-farm collector systems has become an issue for grid owners. PD measurements of the cable systems can give good diagnostics, detect aging and pinpoint faults. Different PD measuring techniques ... -
Correlation Between Electroluminescence and Partial Discharges in Silicone Rubber Used for High Voltage AC Subsea Connectors
Midttveit, Øystein (Master thesis, 2018)Processing of oil and gas has been performed on topside installations close to the wells. In the future, wells will be further away from the infrastructure and more processing will be performed on the seabed. This will ... -
Development of Test Methods for a Combined DC Power and Fiber Optic Deep Water Subsea Cable - Effect of DC Pre-stress on AC Withstand Strength
Meyer, Hans Kristian Hygen (Master thesis, 2015)Repeatered fiber optic submarine cables require a very high reliability. The cables operate at a voltage of 10 kV DC to supply electrical power to the repeaters that are placed every 50-70 km along the cable to amplify the ... -
Diffusjon av vann i sotfylte kappematerialer for polymere sjøkabler
Håkonseth, Gunnar (Master thesis, 2011)Vanntrevekst er den viktigste årsaken til aldring i polymerisk isolasjon i mellomspenningskabler. Sia vanntrær ikke dannes ved lav relativ fuktighet (R.H.), er det viktig å holde relativ fuktighet i isolasjonen lav så lenge ... -
Effect of Elastic Modulus on the Tangential AC Breakdown Strength of Polymer Interfaces
Kantar, Emre; Ildstad, Erling; Hvidsten, Sverre (Journal article; Peer reviewed, 2018)Solid-solid interfaces between insulating materials dictate the long-term electrical properties of the complete insulation system. This paper presents theoretical and experimental investigations aiming to address the impact ... -
Effect of Material Elasticity on the Longitudinal AC Breakdown Strength of Solid-Solid Interfaces
Kantar, Emre; Ildstad, Erling; Hvidsten, Sverre (Journal article; Peer reviewed, 2019)Solid-solid interfaces between insulating materials dictate the long-term electrical properties of the complete insulation system. This paper presents theoretical and experimental investigations aiming to address the impact ... -
Electrical Treeing and Partial Discharge Behaviour in Epoxy Nanocomposites with in situ Synthesized SiO2
Adnan, Mohammed Mostafa; Ve, Torbjørn Andersen; Hvidsten, Sverre; Ese, Marit-Helen Glomm; Glaum, Julia; Einarsrud, Mari-Ann (Peer reviewed; Journal article, 2023)The electrical treeing resistance of epoxy-SiO2 nanocomposites prepared by synthesizing functionalized SiO2 nanoparticles directly in epoxy was investigated and compared to pure epoxy (diglycidyl ether of bisphenol-A). ... -
Elektrisk trevekst i isolasjonsmaterialer for høyspente AC konnektorer - Effekt av syntetisk ester og hydrostatisk trykk
Gravaune, Rune (Master thesis, 2015)En subseakonnektor er et komplekst isolasjonssystem som brukes til å koble sammen kabler, noder osv. på havbunnen. Silikon er et polymerisk materiale som er egnet bl.a. som membran til å svipe av vann fra kontakten ved ... -
Elektrisk trevekst og partielle utladninger i silikongummi for HVAC konnektorer - Innvirking av hydrostatisk trykk og olje
Spurkeland, Ingvild (Master thesis, 2016)Konnektoren er en viktig komponent for kraftforsyning av subsea utstyr og er regnet som en av de mest kristiske komponentene. For å sveipe av vann når konnektoren kobles til kan blant annet silikon brukes. Silikonmaterialet ... -
Epoxy-Based Nanocomposites for High-Voltage Insulation: A Review
Adnan, Mohammed Mostafa; Tveten, Erlend Grytli; Glaum, Julia; Ese, Marit-Helen Glomm; Hvidsten, Sverre; Glomm, Wilhelm; Einarsrud, Mari-Ann (Journal article, 2018)Epoxy nanocomposites, with inorganic oxide nanoparticles as filler, can exhibit novel property combinations, such as enhanced mechanical strength, higher thermal conductivity, increased dielectric breakdown strength, and ... -
Examination of Longitudinal AC Breakdown Strength of Dielectric Surfaces as a function of Elastic Modulus
Kantar, Emre; Hvidsten, Sverre; Ildstad, Erling (Journal article; Peer reviewed, 2017)This paper examines the influence of the elastic modulus of the polymer insulation on the tangential AC breakdown strength (BDS) of polymer interfaces theoretically and experimentally. In the experiments, four different ... -
Future Design of Subsea High Voltage Cables for Offshore Renewables - Water tree growth from contaminants of oxidized polyethylene
Jørgensen, Stian (Master thesis, 2023)Høyspent sjøkabel er en nøkkelkomponent i offshore energiproduksjon fra vind eller sol. I kablene som kobles mellom slike installasjoner er det ikke ønskelig med en vanntettende barriere av bly. Dette er både av hensyn til ...