In order to promote the systematization and the intelligent control of all key links in the whole process of professional of management and control of relay protection operation, an intelligent operation and control system based on large data is explored and constructed. On the basis of relay protection data center, four scenario applications of key links in the whole process of field operation and maintenance are constructed, including site visual operation and error prevention early warning, remote operation and maintenance, factory maintenance and mobile electronic operation. Six advanced applications for technical control of relay protection operation are realized, including working condition evaluation and trend prediction, grid fault analysis, intelligent diagnosis of action and behavior, near-real-time online monitoring, SCD intelligent control and setting calculation. The system is helpful for solving a series of problems in all key links in the operation, maintenance and overhaul of substation and problems in relay protection professional technical management, which improves the level of safety operation management and control of relay protection equipment. This work is supported by Science and Technology Project of the Headquarter of State Grid Corporation of China (No. 521104170012) and Science and Technology Project of State Grid Zhejiang Electric Power Co., Ltd. (No. 5211JX1400LB and No.5211WZ15013Q).