Modelling of multi-megawatt wind turbines for EMI and EMS investigations by a topological approach

Abstract

Todays installed multi-megawatt wind turbines (WT) form highly diverse system due to very complex control devices. Thus, special attention has to be paid to the electromagnetic compatibility (EMC) of the wind turbine. This contribution deals with different electromagnetic interference (EMI) and susceptibility (EMS) effects within the wind turbine. A well-known susceptibility problem of constructions and buildings with large vertical dimensions is the threat situation due to lightning phenomena. On the one hand, the high amplitude of the lightning current effects destructions of infrastructure directly. On the other hand, the transient electromagnetic fields caused by this lightning current could lead to disturbances as well as destructions of electronic devices inside the wind turbine. Furthermore, common-mode currents icm on the power lines between the generator and the frequency converter will cause EMI effects during the normal operation mode. These I cms lead to radiated emissions to the WT's environment as well as to transient disturbing fields inside the WT, which might interfere with the control unit (CU) and the condition monitoring system (CMS). These issues will be investigated in this contribution. Therefore, the electromagnetic topology (EMT) will be applied to the wind turbine. The EMT delivers useful information in order to increase the WT's susceptibility and ensure a high degree of availability.