| 摘要 |
PURPOSE:To detect internal partial discharge with high sensitivity by connecting a core and a core clamping device as grounding structures as the contents of a transformer to a grounded tank by grounding wires and mounting an impedance element or a current transformer to the grounding wires. CONSTITUTION:Partial discharge generated in a tank 7 is produced among a winding 5 as a high-voltage charging section and grounding structures, but core clamping devices, such as a core 1 or a patch 2, a clamp 3, etc. are positioned where nearer to the winding 5 than the tank 7 as the grounding structures, and the probability of partial discharge generated among these core clamping devices and the winding 5 is higher than partial discharge generated in the tank 7. When partial discharge is generated among these grounding structures and the winding 5, all of discharge currents at high frequency based on partial discharge pass through grounding wires 8a, 8b and flow through the tank 7 because charges flow into the grounding structures and the potential of the grounding structures is floated from the tank 7 by an insulating sheet 6. A voltage drop generated by the discharge currents is produced at both ends of an impedance element 9, the voltage is measured by a lead wire 11, and internal partial discharge can be detected. |
