| 摘要 |
<P>PROBLEM TO BE SOLVED: To recognize occurrence of a fault in a power system correctly by eliminating an error in the sampling timing of electric quantity data. <P>SOLUTION: In the digital protective relay with a time of day synchronizing function for judging the occurrence of a fault in a power system by comparing an electric quantity of sampling timing specified based on a reference timing transmitted from a time of day signal generator 4 to a time of day synchronizing means 2 with a judgment value, the time of day synchronizing means 2 comprises a circuit 21 for receiving an indentification code and time of day data delivered from the time of day signal generator 4 through a communication medium L, a code identifying circuit 25 for identifying the reference timing on condition that a received indentification code coincides with a desired code, a circuit 23 for calculating the sampling timing from the identified reference timing and the time of day data, and a sampling synchronization circuit 24 for specifying the sampling timing of the digital electric quantity from the sampling timing thus calculated. <P>COPYRIGHT: (C)2004,JPO |
