A substation instrument control system is disclosed. The substation instrument control system includes a plurality of transformers that generate a plurality of waveform signals representing electric properties of a substation instrument main body. A merging unit is communicatively coupled to the plurality of transformers and includes a signal processing unit and a control unit. The signal processing unit receives the plurality of waveform signals from the plurality of transformers and converts the plurality of waveform signals to a digital signal. The control unit controls operation of the signal processing unit using a setting data. An intelligent electronic device is communicatively coupled to the merging unit and receives the digital signal from the merging unit.
