The connection of wind turbines (WTs) and wind farms (WFs) to the grid is subject to testing their electrical characteristics, including the assessment of several power quality related aspects. These are directly related to the correct operation of power networks. For example harmonics generated by the grid-side power converters, especially in case of variable speed wind turbines, may be of critical importance in power systems where harmonic resonance conditions exist. Therefore, according to the relevant standards, the measurement of several parameters such as the voltage flicker emission and harmonic current distortion caused at the point of common coupling (PCC) of WTs is indispensable for obtaining both the power quality certificate and the grid interconnection approval.

The Laboratory for Wind Turbine Testing (LWTT) of CRES has developed and uses dedicated measuring systems compliant with the IEC 61400-21 standards series. The measurement procedure can be equally applied to individual turbines and wind farms. This procedure may also be used as part of the certification scheme for power quality characteristics of grid connected WTs.

The LWTT of CRES is a founding member of MEASNET Power Quality Expert Group and continually follows international developments in the field of power quality of WTs.

The Laboratory for Wind Turbine Testing of CRES is accredited according to the ELOT-EN ISO/IEC 17025:2005 by ESYD (Hellenic Accreditation System) under Certificate No 647 for Testing and Calibrations. The accreditation scope of the Laboratory includes Power Quality measurements of grid connected wind turbines.