Discussion on cascade-connected multiterminal UHVDC system and its application

According to the development of UHVDC and MTDC technology, the cascade-connected MT-UHVDC system is presented. This paper introduces characteristics of this kind of MTDC system, including electric structure and requirements for equipments and control system and its application in the power system. Based on this new transmission solution, and with the UHVDC planning projects in China in the future, the MT-UHVDC demonstration project is selected by system analysis and comparison, which considering the problems of load distribution and short circuit current level and system stability and engineering cost and so on.