| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection relay device capable of accurately establishing sampling synchronization even if there is a difference between uplink and downlink transmission delay periods of time when the sampling synchronization is controlled by opposite transmission.SOLUTION: A protection relay device 10 comprises: measuring means 5 that measures periods of time (TM and TF) from specific timing when a first protection relay device or a second protection relay device performs sampling to timing when the first protection relay device or the second protection relay device receives data of the sampling performed by the second protection relay device or the first protection relay device at the specific timing and measures a time difference (TF-TM) therebetween; setting means 6 for setting a predetermined value (TDD) on the basis of the time difference (TF-TM); synchronization error detecting means 7 for detecting a difference between the time difference (TF-TM) and the predetermined value (TDD) as a synchronization error (&Dgr;T); and synchronization controlling means 8 for controlling the sampling timing of the first protection relay device or the second protection relay device such that the synchronization error (&Dgr;T) becomes 0. |
