3　Design of System Connection of HVDC Converter Station（Primary System）

3.1　Design Basis and Principles

3.1.1　Design background shall be provided.

3.1.2　Design input，such as planning and design of power grid，planning and design of power transmission from large power plants and review and suggestions concerned，justification of system schemes in this project and review and suggestions concerned，as well as requirements for design of system connection in this project，shall be provided.

3.1.3　The design level year，long-term level year and transition level year shall be considered.

3.1.4　Other design principles shall be provided.