Wind parks are known as sources of harmonic distortion. The emission at the classical harmonic frequencies (low order non-triplen odd harmonics) is however low. Potential problems with connecting individual turbines and wind parks occur at non-standard frequencies, mainly due to harmonic resonances. Next to the harmonic currents driven by the emission from the turbines, studies should also consider the currents driven by the harmonic background distortion.Godkänd; 2014; 20130616 (matbol