| 摘要 |
PURPOSE:To accurately detect a fault section by setting up a communicating control line to connect a zero phase current transformer and its secondary terminal in each distribution line section even when circulating zero phase current exists in a loop. CONSTITUTION:When a ground fault occurs at a point 7, ground fault currents Iof1 and Iof2 are applied. The currents iof1 and iof2 corresponding to the primary pass ground fault current are induced at the secondary side of zero phase AC devices 4-1 and 4-2 and applied. Ground direction relays 5-1 and 5-2 operate and detect that there occurs a ground fault in the section between the zero phase current transformers 4-1 and 4-2. This permits breakers 3-1 and 3-2 to be tripped and the fault point 7 to be separated from a power supply. |
