Performance of Insulation of DC/DC Converter Transformer for Offshore Wind Power Applications
Paper in proceedings, 2020

High voltage direct current transmission is an effective way of energy transportation from offshore wind farms to the grid. One of the most economical solutions to realize it is based on a series connection of the wind turbines. This technology requires implementation of a DC/DC converter incorporating a special transformer operating at high DC voltages with superimposed high frequency components. To design the high voltage insulation of such a transformer, the dielectric properties of the materials constituting the insulation are to be known in a wide range of variations of the electric field and temperature. In the present study, results of the measurements of field and temperature dependencies of the electric conductivities of a typical high-quality mineral transformer oil and oil-impregnated pressboard are reported. The measurements were performed at different combinations of voltage-temperature stresses reflecting the insulation’s operation condition. The obtained data are used for performance evaluation of the insulation system of a prototype of the transformer.

, medium frequency transformer

HVDC power transmission

, dc/dc converter

electric conductivity

, oil-paper insulation


Mohammad Kharezy

RISE Research Institutes of Sweden

Hassan Reza Mirzaei

University of Zanjan

Torbjörn Thiringer

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Joakim Rastamo


Marcus Svensson


Tatu Nieminen

RISE Research Institutes of Sweden

Yuriy Serdyuk

Chalmers, Electrical Engineering, Electric Power Engineering, Power grids and Components

Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP

00849162 (ISSN)


IEEE Conference on Electrical Insulation and Dielectric Phenomena
Virtual, ,

Design av kostnadseffektivt DC-baserat uppsamlingsnät för innanhavsvindkraftspark medelst seriekopplade högfrekvenstransformatorer

Swedish Energy Agency, 2017-11-01 -- 2020-10-31.

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