TO CANYON RIM Notes Dom & intermedia the tower grounding or counterpoise more strall be Ground cable to be 500-MCM annealed copper unless otherwise cables and rods shall be installed in accordance with No conductor shall be embedded in concrete footings. Indicates buried insulated lighting, power, control or communication cables. Indicates ground rods. Indicates bolted connection END OF YARD GRADING -Ground rods spacem 16' to 20' 345 KV BUS STRUCTURE 345/230KV TRANSFORMER AREA 230KV BUS STRUCTURE FOR GROUNDING THIS AREA SEE DRAWING (5570-204) DETAIL Counterpo PLAN Figure 228.-Switchyard key grounding plan. GROUND FENCE EVERY 30 GROUND RODS SPACED 15-20′ 115. SERVICE FACILITIES. Since the switchyard is located comparatively near the powerplant, a service building was not provided in the switchyard. 116. SPECIAL PROBLEMS. The major problem in design of the switchyard was the lack of firm commitments for the power generated at Glen Canyon Powerplant at the time the completion contract had to be awarded. The specifications were issued with plans for a 230/138-kilovolt transformer with delivery to the city of Page and future delivery to Garkane Electric Association at 138 kilovolts. This was later modified to have Page supplied through Arizona Public Service Co. with delivery at 25 kilovolts. The 230/138-kilovolt transformer and the 138-kilovolt yard were deleted from initial installation and the 25-kilovolt switchyard enlarged. After the 25-kilovolt switchyard had been installed, both the Arizona Public Service and Garkane Electric Association decided to take delivery at 69 kilovolts. At this stage of construction, the most economical way to accomplish this delivery was to step up power from the 25-kilovolt bus. Later, if a requirement develops, a 230/138-kilovolt transformer with delivery at 138 kilovolts and a 138/69-kilovolt transformer may be provided to carry the additional load. |