Protective practices in high-voltage transmission

THE BONNEVILLE POWER Administration has adopted 345 kv for transmitting large blocks of power in the Pacific Northwest. The high initial investment required to transmit power at the higher voltages dictates the necessity for closely engineered practices. Revisions in practices that have resulted in lower costs for the 230-kv grid will be adopted for the 345-kv circuits and include: (1) reduced insulation levels, (2) high-speed automatic switching, (3) reduced lightning arrester levels, (4) elimination of provision for continuous overhead ground wire, (5) use of large single-phase autotransformer banks, and (6) elimination of spare single-phase transformers.