this paper describes the plan design and technical features of 220kV Wangtie Smart substation, which includes many technical innovations, such as integrated measurement, control & protection devices, new busbar differential protection synchronization, adaptive sampling delay compensation of optical longitudinal differential protection, sampled value transmission mode based on online switching of dual network, online monitoring and smart alarm of communication network. Practice proves that, compared traditional substations, the construction cost as well as maintenance and labor costs of smart substation are reduced significantly, and smart substation is widely used.