Transient and short-circuit analysis in wind parks with 36kV cable grid and vacuum circuit breaker

Research Project, 2017 – 2019

In this project it is investigated how the high frequency transients (HF) in a cable grid influence connected equipment. Both generation and propagation as well as protection is studied. Measurements in Stor-Rotliden’s wind farm where transformer failures occurred are planned in the project. In comparison with the previous work in this field, the focus here is on the design of grounding systems (GS), especially their HF characteristics with different earthing resistances. Component models derived in a previous Vindforsk project are improved and the results are generalized so that they can be applied to components of different sizes. Analysis of different GS is performed and the importance of different factors that influence generation and propagation of transient overvoltages is determined. Later it is analyzed how the transients influence connected components, and what protection is needed.