Online monitoring system for measuring device

The invention discloses an on-line monitoring system for a measuring device. The on-line monitoring system comprises a voltage transformer on-line monitoring device, a merging unit, a data processing device and an on-line monitoring background, the online monitoring background is used for displaying the received first measurement data, second measurement data and third measurement data in real time; respectively setting alarm upper and lower limits and fault upper and lower limits of the first measurement data, the second measurement data and the third measurement data, and respectively carrying out alarm or fault judgment on the received first measurement data, the second measurement data and the third measurement data; and when any measurement data is judged to be faulty, fault type judgment is performed according to preset data between redundant systems, and the relevance between the state of the measurement device corresponding to the measurement data judged to be faulty and the fault type is obtained acc