| 摘要 |
<p>PURPOSE:To perform reliable tests by opening during breakdown strength tests and closing during operation a contact capable of switching provided between the ground and a strengthening zinc oxide element installed on the grounding side of an zinc oxide type lightening arresters with one end of a center shaft of a tank for filling a gas on the power application side and the other end on the grounding side. CONSTITUTION:A zinc oxide type wall lightening arrester 101A has a plurality of zinc oxide elements 82 and strengthening oxide zinc elements 82' connected in series along the center axis of a tank 40-2 filled with a gas during operation with the bottom end connected to the grounding side and the top end connected to the power application side. A freely switching grounding switchgear 130 is provided at the connecting point between the zinc oxide element 130 and the strengthening zinc oxide element 82', and a contact at fixed portion 131 is connected to the power application side and a contact at movable side 134 is insulated and pulled out into air from the tank 40-2 and then connected to a grounding conductor 22. At the time of breakdown strength tests before starting operation, the grounding switchgear 130 is opened and a test voltage is applied and the grounding switchgear 130 is closed during operation. By doing this, highly reliable breakdown strength tests can be easily performed.</p> |
