In view of such problem of electronic instrument transformer as weak long-term stability and short operation time

the online monitoring system of electronic instrument transformer based on IEC61850 is briefly designed.An online monitoring and analysis platform of electronic instrument transformer based on big data is set up.The HDFS is selected for mass data storage and ROLAP and MOLAP are selected for data analysis and screening.The on line monitoring mathematical model of the electronic instrument transformer based on the connection-less hierarchical coding is given with consideration of such shortcomings of conventional star model as high connection operation cost and large data redundancy so to achieve the improvement of the conventional model.The dimension information table is compressed by coding and stored in fact table to reduce storage overhead.It is shown by the test result that the loading speed of this model is about 44% of that of the conventional model and the storage cost is about 30%-40% of that of the conventional model.This model has feasibility and provides a new idea for the analysis of large-scale data in power grid.