【正文】 coordinated development at all levels of power transmission and distribution under the smart grid goals, and propose the design principles about the coordinated development of the 5 power transmission and distribution planning at all levels。800kV, 177。s Smart grid The basic development goal of power grid is to form a security and economical power grid. Constructing smart grid firstly depend on strong physical power grid. China speeding up the construction the power grid with UHV grid as backbone and subordinate grids coordinated development at all levels. In the technical and institutional, equipment manufacturing and project put into practice aspects has laid down solid basis for the development of smart grid [16]. 8 China pays more attention to research and project implementation, many achievements in smart grid have been acplished in China. To be specific, China has already research and implementation in following technical aspects: Generation link: In the power generation link includes distributed generation, renewable energy generation, generator and power system coordinate operation, and energysaving oriented dispatching technology and autogeneration control. Transformation link: In the power transformation link includes UHV AC and UHV DC transmission, FACTS, digital substation technology, PMUbased W AMS, DMS, stateoriented maintenance and so on. Distribution and supply link: In the power distribution and supply link includes distribution automation system and feeder automation system, custom power, autometering, Automation measurement technology and electric automobile charge power station construction and so on. Dispatching link: In the Dispatching link, much research and application have been carried out, such as next generation dispatch technology supporting system, four main dispatch application platforms, dispatch technology of energysaving generation, online early warning and coordinated security and defense technology, integrated model management, massive information process technology, intelligent visualization, dispatch defense technology for extreme disaster. Information building link: In the information building link includes construction of system information collection, load management system, automatic meter reading system and other related systems. After promoting of marketing information work for many years, the coverage of users with electricity collected automatically improves every year, scope and effect of the system is in gradual expansion, it has played an active role in the pany39。s power is generated by dirty coal plants. The government has stated that it wants to clean up its act by boosting renewable power generation to 15 percent of the total power supply by 2020. Chinese smart grid proposals call for the integration of renewable power sources, including wind and solar. The current power grid isn39。s power system_ So, this determined the smart grid of China with the mon characters of smart grid, it with the unique characters of large sending ends, large receiving ends, large power transmission grid [69]. Smart grid development in china is bases on information technology, munication technology, puter technology with the high integration with infrastructure of generating, transmission and distribution power system [1013]. Smart grid development in china addresses many new challenge and requirements for power system planning and operation in 9 key technical aspects. To response the challenge, the paper presents main research contents and key technologies in the area of power system planning and operation, and proposed detailed implementation procedure and anticipated goals. Finally, some measures and suggestions for power system planning and operation about China smart grid development are given in the paper. II. DEFINITION AND CHARACTERISTICS OF SMART GRID A. The Definition of Smart Grid Based on physical power grid, smart grid is a new type power grid which highly integrates modern advanced information techniques, munication techniques, puter science and techniques with physical grids. It has many advantages, such as improving energy efficiency, reducing the impact to environment, enhancing the security and reliability of power supply and reducing the power loss of the electricity transmission work and so on. The objectives of smart grid are: fully satisfy customer requirements for electrical power, optimize resources allocation, ensure the security, reliability and economic of power supply, satisfy environment protection constraints, guarantee power quality and adapt to power market development. Smart grid can provide customer with reliable, 4 economical, clean and interactive power supply and valueadded services. B. The Characteristics of Smart Grid Smart grid holds the promise that the power sector can go green by not simply reducing the use of dirty power generation methods but instead bee a system that can take more aggressive measures to lower greenhouse gas emissions through efficient integration of renewable energy sources. Smart grid that focus on improving demandside management for energy and promoting renewable energy could be a transformational force that redefines the way people view energy generation, transmission and consumption, in that such grids would encourage active engagement by the broader society, not just power sector specialists. Smart grid mainly has features as secure and reliable, efficient and economical, clean and green, flexible and patible, open and interactive, integrated and so on [1415]. ( 1) Secure and Reliable: The power grid is still to maintain the power supply capacity to the users, rather than a large area power outage when big disturbances on the power grid, faults, natural disasters and extreme weat