| 摘要 |
PURPOSE:To link different systems uninterruptibly without causing loop current by turning a semiconductor switchgear ON based on AND condition of the open command signal for a section switchgear and a voltage drop signal then turning a loop switchgear ON and turning the semiconductor switchgear OFF. CONSTITUTION:When the section P between section switchgears 5 and 6 in system A is separated from the system for the purpose of work, open commands are fed to the switchgears 5, 6 while simultaneously a signal '1' is fed to the AND gate 22 in a different system interconnection apparatus 25. Upon opening of the section switchgears 5, 6 voltage at point X starts to drop. The voltage drop is detected through a voltage drop detection circuit 21 and the AND gate 22 turns a thyristor switchgear 19 ON. Since power is fed from system B to a load 13, the voltage drops only slightly and power can be fed to the section Q without interruption. Thereafter, the loop switchgear 11 is closed through a loop switchgear throw-in circuit 24. |
