Today's multimedia services are far beyond just the voice and data services:they have been diversified tremendously after fueled by the advancement of network infrastructures as well as the sudden surge of multime...Today's multimedia services are far beyond just the voice and data services:they have been diversified tremendously after fueled by the advancement of network infrastructures as well as the sudden surge of multimedia data itself.Currently,researches on metadata insertion,management and transfer keep going very well in order to provide a variety of services to users.In this paper,we propose the design and implementation methods of digital contents metadata system for insertion,storage and retrieval of metadata.The performance evaluation shows that the proposed method performs better than the existing method.展开更多
As an emerging trend in power grid development,the AC/DC hybrid power grid presents the characteristics of multi-type DC links and large-scale AC/DC interconnection.However,existing research on AC/DC power flow calcul...As an emerging trend in power grid development,the AC/DC hybrid power grid presents the characteristics of multi-type DC links and large-scale AC/DC interconnection.However,existing research on AC/DC power flow calculation is mainly based on single-object models,ignoring the complex interactions and interdependencies between the AC system and various types of DC links in the hybrid power grid,such as LCCHVDC,MMC-HVDC,and LCC-MMC hybrid HVDC.Therefore,this paper proposes a power flow calculation algorithm for large-scale AC/DC systems with multi-type DC links.Firstly,a CIM/XML document conversion strategy applicable to the AC/DC system is proposed.Then,a unified modeling method is used to derive the power flow model of the AC/DC system,and a unified iterative algorithm for the large-scale AC/DC system with multi-type DC links is proposed.Finally,the algorithm’s correctness and effectiveness are verified by comparing it with actual measurements from the Southern Power Grid of China,with a voltage deviation of less than 1%.The research shows that the proposed algorithm has good convergence and high computational efficiency,which is applicable to power flow calculations in large-scale DC-embedded hybrid AC/DC grids in the future.展开更多
基金The MSIP(Ministry of Science,ICT&Future Planning),Korea,under the ITRC(Information Technology Research Center)support program(NIPA-2013-H0301-13-2006)supervised by the NIPA(National IT Industry Promotion Agency)
文摘Today's multimedia services are far beyond just the voice and data services:they have been diversified tremendously after fueled by the advancement of network infrastructures as well as the sudden surge of multimedia data itself.Currently,researches on metadata insertion,management and transfer keep going very well in order to provide a variety of services to users.In this paper,we propose the design and implementation methods of digital contents metadata system for insertion,storage and retrieval of metadata.The performance evaluation shows that the proposed method performs better than the existing method.
基金supported by the Science and Technology Project of China Southern Power Grid(ZDKJXM20200052).
文摘As an emerging trend in power grid development,the AC/DC hybrid power grid presents the characteristics of multi-type DC links and large-scale AC/DC interconnection.However,existing research on AC/DC power flow calculation is mainly based on single-object models,ignoring the complex interactions and interdependencies between the AC system and various types of DC links in the hybrid power grid,such as LCCHVDC,MMC-HVDC,and LCC-MMC hybrid HVDC.Therefore,this paper proposes a power flow calculation algorithm for large-scale AC/DC systems with multi-type DC links.Firstly,a CIM/XML document conversion strategy applicable to the AC/DC system is proposed.Then,a unified modeling method is used to derive the power flow model of the AC/DC system,and a unified iterative algorithm for the large-scale AC/DC system with multi-type DC links is proposed.Finally,the algorithm’s correctness and effectiveness are verified by comparing it with actual measurements from the Southern Power Grid of China,with a voltage deviation of less than 1%.The research shows that the proposed algorithm has good convergence and high computational efficiency,which is applicable to power flow calculations in large-scale DC-embedded hybrid AC/DC grids in the future.
