| 摘要 |
A digital protective relay comprises a protective relay arithmetic processing unit for judging, based on a relay judgement quantity obtained by converting a system electric quantity into a digital value, whether in an operating state or in a non-operating state, and a time synchronizing unit for inputting a time reference signal from outside and synchronizing an internal timer of the digital protective relay with an external reference time. The time synchronizing unit includes an A/D converting unit for A/D converting the time reference signal inputted from outside with a resolution of at least 2 bits, and a decoding unit for decoding a time code signal by making a judgement as to a magnitude of the time reference signal with respect to a digital value obtained by the A/D converting unit. |
