電氣專業(yè)外文翻譯---抗雷擊架空配電線路的可靠性-文庫吧資料
2025-01-12 17:44本頁面
【正文】 of dissipating lightning energy to earth. The number of re closer actions and their resultant momentary outages are also reduced. This is beneficial for critical facilities and processes which cannot tolerate even momentary outages. An additional benefit is that outages due to animal contact are also reduced because of the greater distance from phase conductor to ground on pole structures. Distribution line equipment to increase line insulation values are off the shelf items and proven technology. New lightning resistant construction typical by utilizes horizontal line posts, fiberglass standoff brackets or any other method which world increase the insulation value. The replacement of standard pin insulators with line post insulators of greater flashover value is an effective means to retrofit existing wood cross arm construction. The doubling and tripling of dead end and suspension insulators is also a means of increasing flashover values on existing angle and deadend structures. Current fiberglass, polymer, and epoxy technologies provide an affordable means to increase line insulation. While the use of increased insulation levels to reduce lightning flashovers and the resultant outages on overhead distribution lines has been thoroughly tested and demonstrated in laboratory and experimental tests [5], long term history field data has positively demonstrated that the use of lightning resistant construction can greatly reduce outages. Field use at ORNL has shown that in areas which are vulnerable to lightning, the use of increased insulation and a smaller shielding angle is an impressive and cost effective means to appreciably increase the reliability of overhead distribution lines. This reliability study clearly illustrates that the insulation requirements for highreliability distribution feeders should be determined not by the 60 Hz operating voltage but rather by withstand requirements for the lightning transients or other high voltage transients that are impressed upon the line. Electrical equipment (switchgear, insulators, transformers, cables, etc.) have a reserve (BE level or flashover value) to handle momentary over volta
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