| 摘要 |
PURPOSE:To prevent incorrect operation of a relay by providing a power source for inputting a predetermined analog amount at a testing terminal of an input converter to identify the selected content of taps, and writing tap value switching selecting information in a memory. CONSTITUTION:A digital protection relay 10 has an input converter 11 and a discriminator 13. Further, a power source unit 14 is provided to apply a reference voltage to a testing terminal 100 of the converter 11. A CPU 13c judges the ON state of a switch 13z at the time of tap changing, and a tap switching selection information forming process is executed. That is, when the switch 13z is closed, a voltage V1' of a current transformer 11a by the power source 14 is read to judge a tap value, and tap value switching selecting information is formed. Then, when the switch 13z is opened, the CPU 13c writes tap value switching selecting information in a memory, and shifts to execution of main process such as a relay decision, etc. |
