| 摘要 |
PROBLEM TO BE SOLVED: To prevent a ground-fault protective relay from malfunctioning due to a residual current occurring at the time of loop connection of power distribution lines. SOLUTION: An amplifier M for ground-fault current on power distribution line is installed between a non-grounding power distribution line system in which a voltage regulator is provided and a ground-fault protective relay that operates by a ground- fault occurring on the distribution line system, and comprises a voltage input part 2 that detects, by the voltage regulator, a residual voltage Vo appearing on the power distribution line on which a ground-fault has occurred, an electric current input part 1 that detects a residual current Io caused by the occurrence of the residual voltage Vo to flow through the power distribution line, a CPU part 5 that discerns between a ground-fault and a loop connection of power distribution lines based on the phase difference between the residual voltage Vo and a reference voltage Vab, and an electric current amplifying part 7 that amplifies the residual electric current Io to output at the time of a ground-fault based on the command delivered from the CPU part 5 while restraining the residual electric current Io being outputted at the time of loop connection of the power distribution lines.
|
