138-kv isolated-phase bus and switching structure

A DEFINITE TREND has been indicated toward higher subtransmission voltages to meet increasing load demands in certain metropolitan areas. High-voltage metal-enclosed isolated-phase bus structures offer a practical and economical solution to the bus and switching needs at these higher voltages and have many advantages such as simplification of arrangement, greater flexibility, and greater safety. Following this trend, the Consolidated Edison Company of New York installed a 138-kv metal-enclosed isolated-phase bus and switching structure at their East River plant. The bus structure provides for four 138-kv incoming circuits and six 69-kv circuits. Limited space made it necessary to mount the equipment at several levels (Fig. 1).