A hybrid of line commutated converters(LCCs)and modular multi-level converters(MMCs)can provide the advantages of both the technologies.However,the commutation failure still exists if the LCC operates as an inverter i...A hybrid of line commutated converters(LCCs)and modular multi-level converters(MMCs)can provide the advantages of both the technologies.However,the commutation failure still exists if the LCC operates as an inverter in a hybrid LCC/MMC system.In this paper,the system behavior during a commutation failure is investigated.Both halfbridge and full-bridge MMCs are considered.Control strategies are examined through simulations conducted in PSCAD/EMTDC.Additionally,commutation failure protection strategies for multi-terminal hybrid LCC/MMC systems with AC and DC circuit breakers are studied.This paper can contribute to the protection design of future hybrid LCC/MMC systems against commutation failures.展开更多
Power reversal control strategies for different types of hybrid line-commutated-converter(LCC)/modular multi-level converter(MMC)based high-voltage direct-current(HVDC)systems have been proposed with the consideration...Power reversal control strategies for different types of hybrid line-commutated-converter(LCC)/modular multi-level converter(MMC)based high-voltage direct-current(HVDC)systems have been proposed with the consideration of system configurations and MMC’s topologies.The studies show that the full-bridge(FB)MMC gives better performance than half-bridge(HB)MMCs in terms of power reversal in hybrid LCC/MMC systems.The modulation method employed in this paper can achieve a smooth online polarity reversal for hybrid LCC/FB-MMC HVDC systems.Additional DC switches and/or discharging resistors may be needed to reverse the DC polarity of LCC/HB-MMC HVDC systems.Based on the proposed strate-gies,the power reversal processes of the studied systems can be accomplished within several seconds.The speed can be changed according to system operation requirements.The effectiveness of the proposed control strategies has been verified through simulations conducted in PSCAD/EMTDC.展开更多
基金supported by the Science and Technology Project of the State Grid Corporation of China,HVDC Systems/Grids for Transnational Interconnections(Project number:SGTYHT/16-JS-198).
文摘A hybrid of line commutated converters(LCCs)and modular multi-level converters(MMCs)can provide the advantages of both the technologies.However,the commutation failure still exists if the LCC operates as an inverter in a hybrid LCC/MMC system.In this paper,the system behavior during a commutation failure is investigated.Both halfbridge and full-bridge MMCs are considered.Control strategies are examined through simulations conducted in PSCAD/EMTDC.Additionally,commutation failure protection strategies for multi-terminal hybrid LCC/MMC systems with AC and DC circuit breakers are studied.This paper can contribute to the protection design of future hybrid LCC/MMC systems against commutation failures.
基金This work was supported by Science and Technology Project of the State Grid Corporation of China,“HVDC Systems/Grids for Transnational Interconnections”,project number:SGTYHT/16-JS-198.
文摘Power reversal control strategies for different types of hybrid line-commutated-converter(LCC)/modular multi-level converter(MMC)based high-voltage direct-current(HVDC)systems have been proposed with the consideration of system configurations and MMC’s topologies.The studies show that the full-bridge(FB)MMC gives better performance than half-bridge(HB)MMCs in terms of power reversal in hybrid LCC/MMC systems.The modulation method employed in this paper can achieve a smooth online polarity reversal for hybrid LCC/FB-MMC HVDC systems.Additional DC switches and/or discharging resistors may be needed to reverse the DC polarity of LCC/HB-MMC HVDC systems.Based on the proposed strate-gies,the power reversal processes of the studied systems can be accomplished within several seconds.The speed can be changed according to system operation requirements.The effectiveness of the proposed control strategies has been verified through simulations conducted in PSCAD/EMTDC.
