絶縁性異物の付着による交流沿面絶縁耐力の低下

抄録

AC flashover voltage in air (ACFOV) decreases, when nylon string is attached on PMMA insulator surface which has a backside electrode. The decrease in ACFOV by the attachment is explained by the generation and the propagation of the negative surface leader along the string. When the contact angle between the H. V. electrode and the insulator surface is in a range from 90° to 120°, some of the negative surface leaders generated proceed along the string to the earthed counter electrode. The magnitude of the negative leader along the string is stronger than that of the leader on the insulator without a string. In the range of the contact angle from 120° to 180°, the negative surface leader which does not appear on the insulator without a string is generated along the string by the attachment. In the both ranges of the contact angle, the negative leader along the string promotes the flashover.