Grid-forming wind power plants
This thesis investigates the application of GFM control strategies in wind power plants (WPPs). In particular, the focus of the work will be on developing an effective GFM control strategy for the energy storage systems (ESS) in WPPs that not only supports the operation of the WPP in various grid conditions, but also offers a certain degree of GFM properties to the overall WPP. To start with, the selection of the most suitable GFM control strategy for wind power applications is made by evaluating and comparing various control strategies available in the literature. The comparison is based on their influence on the frequency characteristics of the converter and robustness of the controller in varying grid strength. To address the transient stability problem of GFM converters during current limitation, a novel strategy based on the limitation of converter's internal voltage vector is developed, which effectively limits the converter current to a desired value and retains the GFM properties of the converter at all times. An experimental setup is used to validate the effectiveness of the proposed limitation strategy in case of various grid disturbances. By implementing the proposed GFM control strategy for the ESS in a test WPP model, it is shown using detailed time-domain simulation results that the GFM behaviour can be offered to the overall WPP. The Network Frequency Perturbation (NFP) plots are used to verify the GFM behaviour of the considered WPP. Furthermore, an overview of various energy storage technologies (ESTs) suitable for providing ancillary services from WPPs is presented. With a focus on the two most suitable ESTs, i.e., batteries and supercapacitors, recommendations are given for design and sizing of the ESS for a given application. Finally, a coordinated control strategy between the WPP and SGs is developed, which facilitates the provision of frequency support from the WPP and at the same time reduces the energy storage requirements for the converter system.
wind power plants (WPPs)
energy storage systems (ESS)
Chalmers, Elektroteknik, Elkraftteknik
This thesis investigates the potential of energy storage systems (ESS) used in WPPs to offer the GFM capabilities to the overall WPP. For this purpose, an effective control strategy for ESS is developed, which not only provides a certain degree of the GFM capability to the WPP but also aids its operation during various grid conditions. This allows a higher penetration of wind power into power system as compared with what can be achieved with today's solutions, thereby supporting the transition to a more sustainable energy system.
Elektroteknik och elektronik
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5278
Room SB-M500, Sven Hultins Gata 6, Chalmers University of Technology, Gothenburg, Sweden
Opponent: Prof. Oriol Gomis-Bellmunt, UPC, Barcelona