System with a merging unit for variably controlling and synchronizing sampling frequency of a secondary converter

A system for variably controlling and synchronizing a sampling frequency, the system comprising:

• a secondary converter configured to collect first analog data from a first sensor and convert the first analog data to first digital data;
• and
• a merging unit configured to collect second analog data from a second sensor and convert the second analog data to second digital data while collecting an output of the secondary converter,
• wherein the secondary converter includes:
• a first analog/digital (A/D) converter configured to perform A/D conversion on a measurement sample signal for measuring a current state of a voltage transformer (VT) or a current transformer (CT) to generate the first digital data;
• a second A/D converter configured to perform the A/D conversion on a protection sample signal based on a measurement range set according to equipment protection standards for the VT or the CT to generate the first digital data;
• a multiplexer configured to selectively collect an output of the first A/D converter and an output of the second A/D converter and transmit the collected output to the merging unit;
• and
• a buffer configured to perform buffering on a latter output among the output of the first A/D converter and the output of the second A/D converter and transmit the buffered output to the multiplexer, and
• wherein the first A/D converter and the second A/D converter divide a reference clock synchronized with a reference signal to generate the sampling frequency, and perform redistribution to be synchronized with an AC synchronization signal when a reference clock frequency is not a multiple of the sampling frequency, the AC synchronization signal being an AC signal used in at least one of the first sensor or the second sensor.