Browsing SINTEF Open by Author "Eberg, Espen"
Now showing items 1-19 of 19
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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; Peer reviewed, 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 ... -
Development of a web-based user-friendly cable ampacity calculation tool
Eberg, Espen; Espeland, Kåre; Hellesø, Svein Magne; Hvidsten, Sverre; Solheim, Kristian Thinn (Journal article; Peer reviewed, 2019) -
Effects of Frequency and Temperature on Partial Discharge Characterization of Stator Windings
Kantar, Emre; Eberg, Espen; Hvidsten, Sverre (Conference on Electrical Insulation and Dielectric Phenomena. Annual Report;2020, Chapter; Peer reviewed, 2021) -
Evaluation of simplified heat transport for power cables in pipes
Solheim, Kristian Thinn; Hellesø, Svein Magne; Eberg, Espen; Kantar, Emre (Chapter; Peer reviewed, 2023)Power cables in air- or water-filled pipes are the thermal bottleneck in many installations. Some parts of the industry reduce the complexity of their numerical models by combining conduction, convection, and surface-surface ... -
Evaluation of Thermal Network Modelling and Finite Element Analysis for Ampacity Rating Calculation of Wind Farm Export Cable
Espedal, Camilla; Hellesø, Svein Magne; Thomsen, Nina Marie; Strand, Henrik; Eberg, Espen (Chapter; Peer reviewed, 2024)Load and temperature data collected from an onshore wind farm export cable during a nine-month period was used to test and evaluate models for transient calculations of cable temperatures. The temperature data was measured ... -
Experimental study on the effect of soil moisture content on critical temperature rise for typical cable backfill materials
Rieksts, Karlis; Eberg, Espen (Peer reviewed; Journal article, 2022)The increased utilization of power grid requires operating power cables close to their thermal limit. Buried power cables in such condition experience thermal instability where thermal resistance increases as the moisture ... -
Frequency Dependence of the Electric Field Grading of End-Winding of Generator Bars
Aakre, Torstein Grav; Enoksen, Henrik; Eberg, Espen; Mermigkas, Athanasios; Hølto, Jorunn (Peer reviewed; Journal article, 2022)To reduce the electric field stresses in the end-winding in hydropower generator bars, a field dependent grading tape is applied in the transition zone from outer corona protection to bare insulation. The design is typically ... -
Full-scale case study of a road crossing thermal bottleneck in buried MV cable installation
Eberg, Espen; Espeland, Kåre; Hellesø, Svein Magne; Hvidsten, Sverre (CIRED Conference Proceedings;2017, Chapter; Peer reviewed, 2017)Infrastructures such as road crossings, are often limiting the ampacity of a cable link due to poor thermal properties. In order to fully utilize the true loading capacity of the cable, thermal modelling with correct input ... -
High Frequency Dielectric Properties and Losses in Partial Discharge Resistant Rotating Machine Insulation
Syvertsen, Hilde Marie Tollefsrud; Eberg, Espen (Chapter; Peer reviewed, 2024)The complex permittivity of glass-fiber and polyimide backed mica tape for winding insulation in rotating machines have been investigated using a dielectric spectrometer. A frequency ranging from 10 ‐2 Hz to 10 6 Hz and a ... -
How to Plug In the Fishing Fleet: Connectors in charging infrastructure for small fishing boats
Mehammer, Eirill Bachmann; Strand, Henrik; Magnusson, Niklas; Solheim, Kristian Thinn; Eberg, Espen (Peer reviewed; Journal article, 2023)Fishing fleets are targeted for electrification in many parts of the world. These vessels represent a large potential for emission reductions by transitioning from fossil to hybrid and electric propulsion. However, a massive ... -
Hybrid Method for Numerical Implementation of Segmented Power Cable Conductors in Finite-element Based Ampacity Calculation
Strand, Henrik; Eberg, Espen; Anders, George J. (Peer reviewed; Journal article, 2022)This paper addresses challenges with modelling of segmented power cable conductors using finite element analysis (FEA) for ampacity calculation. Segmented conductors improve current distribution by minimizing skin and ... -
HydroStator : hovedfunn og resultater i KPN-prosjektet HydroStator
Berg, Gunnar; Eberg, Espen; Aakre, Torstein Grav; Ildstad, Erling; Kantar, Emre; Nysveen, Arne (SINTEF Rapport;, Research report, 2022)Modeller som beskriver temperatur- og frekvensavhengighet til elektriske delutladninger er utviklet og viser at tilstandskontroll med den mer praktiske VLF-metoden som benytter 0,1 Hz høyspenning er representativ for 50 ... -
Implementation of finite element analysis and hybrid IEC-models in online ampacity tool
Eberg, Espen; Hellesø, Svein Magne; Strand, Henrik; Engebrethsen, Marius; Østerberg, Dan; Espeland, Kåre; Jacobsen, Rune (Chapter, 2023)Current tools for ampacity calculations are based on analytical expressions, and empirical expressions for complex laying geometries that in practice cannot be solved analytically, formulated in the IEC standards. Non-standard ... -
Multi-stress Cyclic Testing of Roebel Stator Bars for Hydropower
Eberg, Espen; Kantar, Emre; Aakre, Torstein Grav (Peer reviewed; Journal article, 2022)A multi-stress test rig was built to investigate the effect of many start-stops (load cycling) on hydropower generator insulation. To emulate real-life start-stops, stator bars were subjected to accelerated temperature ... -
Optimisation of power cable ampacity in offshore wind farm applications
Høyer-Hansen, Martin; Hellesø, Svein Magne; Solheim, Kristian Thinn; Mehammer, Eirill Bachmann; Eberg, Espen; Pedersen, Per Atle (Peer reviewed; Journal article, 2022)Inter-array power cables are used to connect wind turbines to the collector and export cable. In the transition from turbine tower to sea, the cable is installed in a J-tube, which has an unfavourable thermal environment ... -
Partial Discharge Inception Voltage of Pigtail Samples with Type II Insulation and Sinusoidal vs Switched Voltage
Aakre, Torstein Grav; Eberg, Espen; Mermigkas, Athanasios; Røkke, Astrid (Chapter; Peer reviewed, 2024)Partial discharge inception voltage (PDIV) under sinusoidal voltage and switched voltage with dV/dt of 20 V/ns have been investigated for pigtail samples with type II insulation consisting of Litz wire as conductor and ... -
Simplified model for heat transport for cables in pipes
Hellesø, Svein Magne; Eberg, Espen (Peer reviewed; Journal article, 2021)This paper addresses challenges with modeling of heat transfer phenomenon for cables in duct or pipes when applying a numerical solution. Heat transport mechanisms between the cable and pipe surfaces are conduction, ... -
Transformatorgjennomføringer - Tilstandskontroll og anbefalinger
Eberg, Espen; Meyer, Hans Kristian Hygen; Foros, Jørn; Berg-Karlsen, Gunnar; Tveten, Erlend Grytli; Aakre, Torstein Grav (SINTEF Rapport;, Research report, 2022)Prosjektet "Tilstandskontroll av transformatorgjennomføringer" har hatt som mål å fremskaffe nødvendige metoder samt kunnskap for å kunne foreta en tilstandsevaluering av transformatorgjennomføringer. Hovedvekten av ... -
Use of Data-Driven Approaches for Defect Classification in Stator Winding Insulation
Kantar, Emre; Cascallo, Jaume M.; Aakre, Torstein Grav; Thomsen, Nina Marie; Eberg, Espen (Peer reviewed; Journal article, 2022)Partial discharges (PD) in the high voltage insulation systems are both a symptom and cause of terminal and impending failures. The use of data-driven methods based on PD measurements will enable predictive strategies to ...