Power Quality In the field of power distribution and transmission, there are different influences which can lead impairments, stress and damage to electrical equipment. Transportation of reactive power through the supply network is uneconomic and the electrical equipment should have to be larger in size. Therefore, the reference reactive power is in the power purchase agreements also set out a lot of costs. Also the generation of circuit feedbacks is regulated in various standards like VDE, DIN, IEC and EN. To minimize and avoid these influences compensation systems and harmonic filters are used, leave by their use significant cost savings. To assess reactive power consumption or circuit feedback generation we arrange on-site network measurements in order to disign adequate facilities. Reactive Power Compensation: Windfarm Substation: 3 MVAr-Compensation ind. / cap. adjustable Various Harmonic Filters: