According to the requirements of high reliability for power supply, it is necessary to monitor on some specific or selected power equipment with high quality in a specific period, which then resulting in some new requirements for automation systems. Under this background, a unified data platform, based on the common device model and the network topology, for power systems is built through integrating the information of equipment and operation from EMS, DMS, GIS and the automation systems in stadiums. The topology models of both the transmission system and the distribution networks are merged, and the data sources and maintenance for all the automation systems could be unified on this platform. Some new advanced applications, e.g. power tracing in the whole network and comprehensive system security assessment, could also be developed based on it. Furthermore, high data quality for automation systems and superior information display is available for specific application requirements based on this platform, and a customizable power automation system, which could better response to the requirements of the customers with high reliability in power supply, could be developed by flexible cutting and focusing on the concerned information and functions. The research in this paper has been applied to the supervisory system for the Guangzhou power system during the 16th Asian Games, which illuminates the high theoretical and practical value of the integrated platform.