Harmonic analysis for grid integration of a large scale offshore wind power plant: A case study for northwest turkey

Harmonics are common problems that constituting a remarkable thread for transmission systems' stability. They have side effects not only on power system operation but also on health of system equipments. Taking precautions to combat these problems is strongly dependent to system operator's ability to simulate harmonics before their effects become visible on the system. Generally simulations made on softwares are prefered for these kind of studies. However commonly used models used for steady state simulations are not reliable on drawing a network's harmonic characteristics. Therefore special models built by considering harmonic impedances must be developed. In this study, first harmonic domain representation of existing Turkish Tranmission Network model is developed. At this process firstly main effective equipments to the grid impedance is deduced as transmission lines and transformers. Then with the help of literature, methods to define these two eqipments' frequency dependencies are revealed. Finally for a case study made on the subject of a possible large scale Offshore Wind Power Plant integration to Türkiye, a harmonic version of the grid at Trakya region is produced. The produced model is used for before connection analysis of the Offshore Wind Power Plant. As a result of the study it is concluded that harmonic domain models produce very different outputs in terms of resonance locations and impedance magnitudes than existing lumped models. Since reliability of model is the key to define the exact locations of resonances, this study proved that using harmonic models for before connection analysis is critical to achive more realistic outputs.