Patent ID: 8923361

Claim:
A protection control apparatus comprising a merging unit configured to merge system electric quantities detected in a power system, convert the system electric quantities into digital data, and output the digital data, the protection control apparatus protecting the power system, the protection control apparatus comprising: the merging unit including: a control-signal output circuit configured to generate a sampling signal in synchronization with a synchronization signal received from outside and output, as a control signal, numbers cyclically counted up every time the sampling signal is generated and the sampling signal; and a data output unit configured to convert the system electrical quantity into digital data based on the control signal output from the control-signal output circuit and output the digital data, wherein the control-signal output circuit includes: a number-of-clocks calculating circuit configured to calculate, based on its own clocks of the number-of-clocks calculating circuit, a first number of clocks in time from a minimum to a maximum of the numbers, a second number of clocks in a cycle of the synchronization signal, and a third number of clocks in time from detection of the synchronization signal until the sampling signal is generated; and a synchronization control unit configured to calculate a difference between the first number of clocks and the second number of clocks, control a cycle of the sampling signal based on the difference and the third number of clocks, and synchronize the generation timing of the sampling signal with the synchronization signal.