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Farhan Hosseini
Research Assistant
University of Tehran
Public Documents
1
Onshore AC Fault Ride-Through Control in Multi-Terminal HVDC Systems
SeyedFarhan HosseiniKordkheili
and 1 more
September 05, 2024
This paper proposes an AC Fault Ride-Through (AC-FRT) control for VSC-Based HVDC systems in accordance with modern grid codes. The presented strategy also provides a backup energy controller for AC faults for cross-control MMCs where the converter total energy is normally regulated through the AC side current. The proposed AC-FRT control is capable of positive and negative sequence voltage support and properly limits current set-points to the specified safe limits accordingly with a tunable response time. Furthermore, the backup energy control allows for a distinct response for AC-FRT operation, independent of the energy controller employed during normal operation. The effectiveness of the proposed methods are validated using time-domain simulations in a Multi Terminal Direct Current (MTDC) grid. Furthermore an analysis is carried out to determine the effects of energy control in Modular Multilevel Converters (MMC) and the AC-FRT controls for different fault scenarios on the AC and MTDC grids interlinked by the converter. The aforementioned analyses will be used to attain a heuristic tuning method for the converter's AC-FRT operation. The AC-FRT control's time constant is the tuning parameter in 2 level VSCs where in the case of an MMC, the backup energy controller can also be designed in tandem with the AC-FRT time constant in order to attain a reasonable balance between AC fault current response time and MTDC grid dynamic variations.