摘要
The high-voltage direct current(HVDC)grid has been recognized as an effective solution for renewable energy integration.Currently,two main development trends for HVDC grids are being studied:a DC breaker based HVDC grid and fault-blocking converter based HVDC grid.Although the former has a perfect performance for fault clearance,its development is still highly constrained by the cost and maturity of DC breakers.The latter can extinguish DC faults by the fault-blocking converters.Without using DC breakers,there is no bottleneck in its technical feasibility.Nevertheless,in fault scenarios,such types of HVDC grids will be blocked at length for air-deionization,which is its main drawback.The aim of this paper is to minimize its power interruption time,by optimizing protection coordination strategies.To cover the most complex cases,the overhead line applications,in which the reclosure actions are required to be implemented,are considered.In this paper,the protection requirements of HVDC grids are first discussed,then the benefits of fault-blocking modular multilevel converters(MMCs)and their fault features are analyzed.Based on this,a control function is designed to reduce the air-deionization time.To minimize the influence of the DC faults,a separation methodology for restarting the system is proposed.The effectiveness of the proposed protection coordination schemes is validated by PSCAD/EMTDC simulations.
作者简介
Sheng Yan received the M.Eng.degree in electrical engineering from Southeast University,Nanjing,China,in 2001.In 2001,he jointed State Grid Electric Power Research Institute(SGEPRI),Nanjing,China,and in 2009,he worked with State Grid Corporation of China(SGCC),Beijing,China.In 2014,he became the director of the Science and Technology Research Ministry of SGCC mainly in charge of the management of the scientific and technological projects,demonstration projects construction and experimental laboratory capacity construction,etc.He is currently pursuing a Ph.D.degree in Southeast University and his research interests mainly involve large grid power automation and smart grid technology.e-mail:52862818@qq.com;Zhiyuan He received the M.Eng.degree and the Ph.D.degree in electrical engineering from China Electric Power Research Institute(CEPRI),Beijing,China,in 2003 and 2006,respectively.In 2006,he joined CEPRI,where he led the VSC-HVDC Transmission Systems Group.In the past years,he has accomplished the study on high power electronics technology for reliable operation of large interconnected power grids.He was a member of CIGRE B4 Working Group 48,and his interests include the VSC-HVDC control and testing technologies.e-mail:hezhiyuan@geiri.sgcc.com.cn;Jie Yang received the B.Eng.and Ph.D.degrees in electrical engineering from Tsinghua University,Beijing,China,in 2005 and 2011,respectively.In 2012,he joined the Global Energy Interconnection Research Institute(GEIRI),Beijing,China.His research interests include control&protection strategies of VSC and HVDC converter technologies.e-mail:yangjie_thu@163.com;Corresponding author:Ming Kong received the M.S.and Ph.D.degrees from Electric Power Research Institute(CEPRI),Beijing,China,in 2011 and 2014,respectively.Currently,he is working with Global Energy Interconnection Research Institute(GEIRI)of the State Grid Corporation of China(SGCC),Beijing,China.His main research interests include VSC-HVDC,DC grid and application.e-mail:kongming@geiri.sgcc.com.cn
