| 摘要 |
PURPOSE:To prevent the stoppage of the supply of electric power to load when the accident of grounding is generated due to the dielectric breakdown of a potential transformer by providing a zero-phase current transformer using a grounding cable and an electric path connected to a secondary coil as primary inputs and a switch being operated by an output from the current transformer and interrupting the transformer and a high-tension electric path. CONSTITUTION:A core 15 insulated from the ground in a potential transformer 10, a grounding cable 17, a zero-phase current transformer 5 and a switch 19 are furnished. The zero-phase current transformer 5 detects grounding currents flowing through the grounding cable 17 through the core 15 from a primary coil 11 or flowing through a low-tension electric path through a secondary coil 13 from the primary coil 11 on the dielectric breakdown of the transformer 10, and the switch 19 separates the transformer 10 and a high-tension electric path 1. Accordingly, when the accident of grounding is generated due to the dielectric breakdown of the transformer 10, the transformer 10 is detached, and the stoppage of the supply of electric power to load can be prevented. |
