Abstract: During the 13th Five-Year period(2016-2020), the Chinese government is promoting long-distance and large-capacity power transmission projects and the UHV power grids have witnessed very fast development. The UHV transmission projects Zhalute in North East China to Shandong and Shengli to Ximeng in North China are important transmission channels mentioned in“13th Five-Year Plan of Electrical Power development”. The planned future power grid will be characterized by large-scale collected power sources delivered outbound by DC transmission, large-scale accession of renewable energy and co-operation of AC and DC grids. The enhanced transmission capacity of DC will bring new challenges and problems to the security and stability of power grid. Assisted by the State Grid Simulation Center, a transient security assessment is made for large-scale power transmission of UHVDC, and an analysis is made on a series of new problems brought about by large-scale outbound power transmission. Possible countermeasures are provided to effectively solve the main security and stability problems brought about by the large-scale outbound power transmission planned in the 13th Five-Year planning.

Key words: 13th Five-Year Planning, renewable energy, large scale outbound power transmission, security and stability