Emission phenomenon of supra-harmonics caused by switching of full-power frequency converter of wind turbines generator (PMSG) in smart grid

In the past decade, the use of wind turbines connected to distribution networks, in order to improve voltage profile, reduce losses and increase reliability and network security have been increasing. Meanwhile, the role of static converters and power electronic devices in connecting and controlling the wind turbine power is important. In order to generate the maximum power, decrease the mechanical stress and control the active and reactive power in the structure of the permanent magnet synchronous generator (PMSG) of 4th generation wind turbines, the full-power frequency converters have been used. Today, with the development of smart grids, the harmonic emission and immunity in the frequency range (2–150 KHz) have found particular importance. Switching in the static convertors of wind power plants causes the emission of the harmonics in the frequency range (2–150 KHz) in distribution networks. The frequency range (2–150 KHz) has not covered enough in power international standards. Majority of power line communication (PLC) systems have been operated in this frequency. However, no major report on the impact of these distribution networks has been provided yet, but these harmonics can cause disturbances in power line communication (PLC) system function. In this article, the emission of harmonics caused by switching of generator full-power frequency converter (PMSG) of a wind unit connected to the medium voltage (MV) network will be simulated and analyzed as real-time in Matlab software. The information of distribution network and wind power plant has been resulted from a real system. The simulation results show that despite the generation of a great spectrum of harmonics in the frequency range (2–150 KHz) by wind turbine frequency converter, due to the resonance of network elements and coupling transformer, the emission of these harmonics over the network is low. However, the harmonics in the range (2–150 KHz) were so large with the possibility to cause dysfunction in power line communications (PLC) systems.