| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection controller which can achieve sampling synchronism not dependent on the transmission line.SOLUTION: A protection controller 10 includes a synchronous oscillator 12 which determines a timing for sampling the quantity of electricity of a system obtained from a power system, sampling phase measurement means 13 for measuring the phase from the quantity of electricity of a system, and synchronous oscillator correction means 14 for correcting the sampling timing of the synchronous oscillator 12. The synchronous oscillator correction means 14 compares a phase measured by the sampling phase measurement means 13 with a phase measured by other device and calculates a phase difference at a value of most approximate phase, and corrects the sampling timing determined by the synchronous oscillator 12 by that difference. |
