Abstract:With the development of smart grid, the existing computing and information processing capability of power system are insufficient to support the realization of smart grid. While cloud computing can integrate the internal processing and storage resources of the power grid, and improve the processing and interaction ability of the power grid. Security and reliability are major barriers for adopting cloud technologies and services for power system. This paper proposes an approach to obfuscate information of power flow, which can ensure the information security of power grid and improve the calculation efficiency of static security analysis of power system in cloud computing environment. Meanwhile no error is introduced in the dc power flow model . Further simulation analysis shows the error introduced in the ac power flow model is small. Moreover the root mean square error grows linearly with the magnitude of obfuscation.