Abstract:UHV substations accumulate large amounts of data during operation. The data size, growth speed and complexity of UHV substations are incomparable to EHV substations. Therefore, it is an urgent problem to make effective use of these abundant data resources to make business decisions. Big data technologies provide new technical methods and tools for UHV substation operation and maintenance. By integrating data collected from the station sensors to a substation cloud platform, the subsystems developed based on the cloud platform can facilitate inspection and failure prediction, and greatly optimize human configuration. This paper first analyzes the data sources and characteristics of current UHV substation, and discusses how big data technologies help UHV operation and maintenance from two aspects of inspection and fault detection. We expound a new inspection mode and introduce the working idea of using big data technology to detect and predict faults. Finally, the key technologies of building UHV substation cloud platform are introduced, and the relative trend is prospected.