Contact Faults in Hybrid AC/DC Power Systems

Latest studies of German system operators recommend the integration of High Voltage Direct Current (HVDC) Systems in existing interconnected Alternating Current (AC) grid structures in order to meet an increased power transport demand over long distances. This leads to a parallel operation of both system technologies. Due to limited area and long authorization procedures for constructing new lines the parallel operation of both systems is also planned in parts on the same right of way or even the same tower, resulting in so called “hybrid AC/DC Systems”. This configuration offers improved grid efficiency as well as an additional degree of freedom for grid operation, by utilizing modern Voltage Source Converter (VSC) stations. On the other hand new challenges have to be coped such as coupling effects between both systems, altered insulation requirements and AC/DC contact faults.