R&D Engineer Ingeteam Power Technology S.A., Navarra, Spain
Presentation Description: Wind energy penetration in the transmission networks has been continuously increasing during the last decades. This situation propitiates integration problems with the electrical grid. Regarding the power converter, these problems can be classified as follows: • Working with very low SCR or quality factor grids: the resonance frequency of the harmonic filter decreases and can destabilize the current control loop. • Subsynchronous resonances: when series capacitors used in long transmission lines interact with the converter control loops, resonances at low frequencies appear. • Parallel resonances: the use of capacitor banks on a wind -farm level can have an influence on the system stability. An accurate modelling of the converter control loops becomes indispensable in order to overcome these challenges. Using SIL and HIL systems meet this requirement but are time-expensive. The modelling of the control loops as linear time-invariant (LTI) systems, instead, allows high agility to run parameter sweeps and test new algorithms. The following workflow is proposed to anticipate grid interaction problems: • Characterization of the particular grid • Analysis of the control loops behavior with that particular grid to obtain the set of parameters or new algorithms to assure the good performance using LTI modelling • Validation of the solution using SIL and/or HIL systems
Identify the necessary parameters for a precise enough grid characterization and understand, using real grid examples, how certain grid types can lead power converter control loops to be unstable.
Understand the issues that must be resolved in order to model the converter control loops as LTI systems with the required accuracy, and describe the possibilities of this kind of modelling regarding the analysis, tuning and development of control algorithms.
Expose the steps to perform a complete validation of the power converter control loops using SIL and HIL systems.