Impedance-based analysis of harmonic instabilities in HVDC-connected Offshore Wind Power Plants

• Published in: International journal of electrical power & energy systems Vol. 106; pp. 420 - 431
• Main Authors: Cheah-Mane, Marc, Sainz, Luis, Prieto-Araujo, Eduardo, Gomis-Bellmunt, Oriol
• Format: Journal Article Publication
• Language: English
• Published: Elsevier Ltd 01.03.2019
• Subjects: Active damping; Energia eòlica; Enginyeria elèctrica; Harmonic stability; Harmonic stability Impedance-based representation Offshore wind power plant Active damping; Impedance (Electricity); Impedance-based representation; Impedància (Electricitat); Offshore wind power plant; Offshore wind power plants; Àrees temàtiques de la UPC; Active damping; Impedance-based representation; Harmonic stability; Offshore wind power plant
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2018.10.031

•A HVDC-connected OWPP is represented using a detailed impedance-based model.•Harmonic interactions are detected as resonances from the grid connection of VSCs.•Main parameters that affect harmonic instabilities are analysed in detail.•A coordinated active damping strategy was presented to mitigate instabilities. HVDC-connected Offshore Wind Power Plants (OWPPs) with a large number of power converters are prone to instabilities due to interactions with converter controllers. This paper analyzes harmonic instabilities in OWPPs connected through HVDC due to interactions with the offshore HVDC converter and the wind turbine converters. An impedance-based model is used to represent a detailed OWPP with fully-rated converter based wind turbines, including the offshore HVDC converter, wind turbine converters, submarine cables and transformers of the offshore AC grid. Harmonic stability is evaluated both from the grid connection point of the offshore HVDC converter and the WT grid side converters. As a result, the influence that parameters of converter control systems and the offshore grid configuration have on harmonic resonant frequencies and stability conditions is analyzed in depth through a sensitivity analysis. Active damping implemented as a feed-forward control is coordinated in all converters to mitigate the harmonic instabilities. Examples of harmonic instabilities and active damping application are validated with time domain simulations in PSCAD/EMTDC.