Visible to the public Grid Code Compliant Modeling and Control of Modular Multilevel Converters during Unbalanced Faults

TitleGrid Code Compliant Modeling and Control of Modular Multilevel Converters during Unbalanced Faults
Publication TypeConference Paper
Year of Publication2019
AuthorsRichter, Michael, Mehlmann, Gert, Luther, Matthias
Conference Name2019 54th International Universities Power Engineering Conference (UPEC)
KeywordsBalancing Control, Collaboration, Converter Control Design, Decoupled Double Synchronous Reference Frame - Phase-Locked-Loop, Decoupled Double Synchronous Reference Frame-Current Control, electric current control, fast fault injection, fault current injection, Fault-Ride-Through capability, Fault-Ride-Through Capability (FRT), German Technical Connection Rules, grid code compliant modeling, Grid Codes, grid currents, grid voltage, High Voltage Direct Current (HVDC), horizontal balancing control, Human Behavior, human factors, HVDC converters, HVDC power convertors, HVDC power transmission, Metrics, Modular Multilevel Converter (MMC), modular multilevel converter control, Phase locked loops, policy-based governance, power convertors, power generation faults, power grids, power system control, pubcrawl, resilience, Resiliency, Safe Coding, Technical Connection Rules (TCR), unbalanced faults

This paper presents necessary modeling and control enhancements for Modular Multilevel Converters (MMC) to provide Fault-Ride-Through capability and fast fault current injection as required by the new German Technical Connection Rules for HVDC. HVDC converters have to be able to detect and control the grid voltage and grid currents accurately during all fault conditions. That applies to the positive as well as negative sequence components, hence a Decoupled Double Synchronous Reference Frame - Phase-Locked-Loop (DDSRF-PLL) and Current Control (DDSRF-CC) are implemented. In addition, an enhanced current limitation and an extension of the horizontal balancing control are proposed to complement the control structure for safe operation.

Citation Keyrichter_grid_2019