| 摘要 |
PROBLEM TO BE SOLVED: To find the current operating point easily for a set point of a reverse time characteristics operation by determining the accumulated operation time of a value corresponding to the operation of a relay having reverse time characteristics and indicating it with reference to a time required for reaching the operating point of reverse time characteristics. SOLUTION: During the protective operation for an object to be protected, a value expressed in terms of fifth harmonic is determined as a value corresponding to the operation continuously or every predetermined sampling time and an accumulated operation time ΣTxn is determined for a predetermined value xn expressed in terms of fifth harmonic. On the other hand, a time required for reaching the operating point of reverse time characteristics is determined with respect to the predetermined value xn expressed in terms of fifth harmonic. Subsequently, an accumulation value =ΣTxn /F(xn) } is determined based on the accumulated operation time ΣTxn and the time F(xn) required for reaching the operating point of reverse time characteristics and the accumulation value =)Txn/F (xn) } is indicated. When the accumulation value is '1' or '100%', a protective relay, i.e., a relay containing harmonic, is operated. |
