Prototype, design, implementation and validation of a harmonics measurement system for wind generators

Wind Turbine Generators (WTG) converters introduce harmonics into the grid, and the guidelines to measure properly this power quality phenomenon are addressed in the standard IEC 61400-21. This paper presents the design, implementation and validation of a harmonic measurement system prototype for wind parks. The prototype was developed in a hardware platform that comprises a real-time controller, a reconfigurable Field-Programmable Gate Array (FPGA) and analog signal acquisition modules for voltage and current. The scalability and fast processing capacity of this hardware setup was suitable to measure harmonics, interharmonics and higher-frequency harmonics according to the recommendations of IEC 61400-21. The results were validated in a laboratory experimental set, comparing the prototype data measures with an Intelligent Electronic Device (IED), both measuring voltage and current signals from a power quality calibrator, where it could be emulated electrical currents containing harmonic components in a wide range of frequencies. The prototype proved to be accurate, even for the higher-frequency harmonics.