Agenda - Council - 06/25/2013 - Laserfiche WebLink

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Benton County, St. Cloud, and Crossroads Substations Changes and modifications will include replacements or upgrades of relays and communication equipment internal to the control house(s), installing fiber optic lines for relaying and transfer trip, installing breakers, reconfiguring line protection, replacing shield wire with fiber optic shield wire, and related modifications. Transmission Structure 39 Jumpers connecting existing lines will be removed and new jumpers will be added to Structure 39 depending on the proposed transmission line re -designations. New single- and/or double - circuit structures will also be constructed near Structure 39 to support the new transmission line connections and re -designations. 2.3 Structures and Conductors The primary structure or tangent structure the permittee shall use for the project is a galvanized steel, weathering steel or wood single -pole structure with braced posts or davit arms. The tangent structures will be approximately 70 feet to 90 feet in height with an average span of 300 feet to 400 feet between structures (500 foot maximum). The steel structures will have up to a 5 foot to 8 foot average diameter foundation at ground surface and taper with height. Approximately 2.7 miles of the new transmission line shall follow and be underbuilt with existing distribution lines along U.S. Highway 10. The permittee shall design the project to fit within these existing easements, thereby requiring less right-of-way while still satisfying the needs of the project. For this segment of the project the permittee shall use the same tangent structures as described above with the addition of a distribution crossarm. Angle structures will be similar in design to the tangent structures described above. Given the limited right-of-way, guyed structures would likely not be necessary. Double -circuit structures may be used for approximately 0.7 miles of the route where existing Line 5509 would be extended from its intersection with Lines 0887 and 0899 to Structure 39. A double -circuit structure may also be required to connect the newly extended Line 5509 from Structure 39 to existing Line 0899 that runs to the existing Benton County Substation. The double -circuit structures will be a galvanized or weathered steel single -pole with davit arms approximately 75 to 105 feet in height with spans of 300 to 500 feet. The phases for the project will be constructed with three single steel supported aluminum conductors (ACSS) which each consist of a single conductor comprised of seven steel core strands surrounded by 26 outer aluminum strands. The separate conductors are 795,000 circular mils or approximately 1.092 to 1.139 inches in diameter. The 115 kV transmission line would be three-phase, 60 Hz (hertz), alternating current line. November 2010 Page 6