【正文】
increasing that reserve, the service reliability is appreciably increased. As the electrical industry gradually moves away from standard wood cross arm construction and moves toward more fiberglass, polymer and epoxy construction, increased insulation methods can be applied as part of new construction or as part of an upgrade or replacement effort. In considering new or upgraded overhead line construction, the incremental increased cost of the higher insulation equipment is d in proportion to the total costs of construction (labor, capital equipment, cables, electric poles, rightofway acquisition), Its cost effectiveness varies with the application and the conditions to which it is be applied. Economic benefits include increased electrical service reliability and its inherent ability to keep manufacturing processes and critical loads in service. Other more direct benefits include less repair of overhead distribution lines, which can have a significant reduction in maintenance cost due to less replacement materials and a large reduction in overtime hours for maintenance crews.抗雷擊架空配電線路的可靠性閃電仍然是架空配電線路上的中斷1的主要原因。 etc.). For simplicity purposes in the analysis, each overhead line was categorized with a nominal voltage construction class (15 kV, 34 kV, or 69 KV). Six of the eight overhead lines (feeders 1 through 6) were built with typical REA Standard horizontal wood cross arm construction utilizing single ANSI Class 555 porcelain pin insulators (nominal 15 kV insulation). The shield angle of the overhead ground wire to the phase conductors is typically 45 degrees. One overhead line (feeder 7) was built with transmission type wood pole construction because the line extended to a research facility which was to have generated electrical power to feed back into the grid. Pole structure of this line are of durable wood cross a construction which utilize double ANSI 523 porcelain suspension insulators to support the conductors (nominal 34 kV insulation). The shield angle of the overhead ground wire to the phase conductors for feeder 7 is typically 30 degrees. In 1969, an