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HomeMy WebLinkAboutRICHARDS LAKE TO WAVERLY TRANSMISSION LINE - SPAR - 12-08 - SUBMITTAL DOCUMENTS - ROUND 1 - APPLICATION (6)Tri-State Richard Lake to Waverly 115-kV Transmission Line Project Site Plan Advisory Review Application Characteristic -Value Span between structures: typical maximum 800 feet Number of structures per mile: with typical range 7-17 Height of structures: typical 65 feet aboveground Height of structures: typical range 60 feet to 88 feet aboveground Minimum ground clearance beneath conductor 24 feet Minimum ground clearance beneath conductor over roads 28 feet Circuit configuration vertical Conductor type and size (circular mils in inches) 477 ACSR 'Hawk' 2617 Shieldwire type and size (inches) 48 fiber optical ground wire, 0.571' 3.2 Modifications to Richard Lake Substation Planned additions to the Richard Lake Substation include a 52-foot-tall A -frame structure where the conductors for the new transmission line attach to the substation and a set of line disconnect switches. These switches help isolate the transmission line from the substation for maintenance purposes. Additional equipment to be installed includes two circuit breakers on concrete slab foundations, four switches and associated stands, three current capacitor voltage transformers (CCVT), and three metering units. A new deadend (angle) structure will be located immediately north of the substation fenceline, and a new deadend structure will be located at the northeast corner of the substation. Thirty-one copies of the plan view (site plan) drawing (labeled RI-101) showing the proposed modifications to the Richard Lake Substation have been submitted with this application. The specific locations of each deadend structure could vary depending on final engineering and design considerations. Eight copies of the architectural elevations of new structures within the substation fenceline (labeled RI-102) have been submitted with this application. 10 May 2008 Tri-State Richard Lake to Waverly 115-kV Transmission Line Project Site Plan Advisory Review Application 3.0 Project Description Within the city of Fort Collins, Tri-State is proposing to construct 0.4 miles of single -circuit, three-phase 115-kV overhead transmission line and to modify the existing Richard Lake Substation to accommodate the new transmission line. This section describes the characteristics of the transmission line and structures, the required modifications to the Richard Lake Substation, the construction workforce, and the project schedule. 3.1 Transmission Line Characteristics The three-phase conductors will be 477-kcmil aluminum conductor steel reinforced (ACSR) with an approximate diameter of 0.858 inches. The typical configuration would be to support the conductors with a single wood structure (pole) with the conductors stacked vertically with a lightning shieldwire placed at the top of the structure. The shieldwire would have an approximate diameter of 0.571 inches and would contain optical fibers to be used solely for Tri-State's communication system. The transmission line will be designed to the more rigid requirements of either the 2007 National Electric Safety Code or RUS Bulletin 1724E-200, Design Manual for High Voltage Transmission lines. The National Electric Safety Code (NESC) is the industry standard for design, clearance, maintenance, and operation of high voltage lines, while the RUS Bulletin provides additional requirements to ensure the quality of the transmission line for lending purposes. Tri-State intends to borrow money from the U.S. Department of Agriculture's Rural Utility Service (RUS) to fund the construction of this transmission line. RUS provides loans to assist rural electric cooperatives with capital improvement projects. The width of the transmission line right-of-way is determined by considering the voltage, structure spacing, and the required clearances to buildings (existing or future) that may be erected adjacent to the transmission line. The 75-foot width ensures that the transmission line will always be in compliance with the NESC and not be a hazard to the public. Because the transmission line angle structures will be self-supporting steel poles on concrete foundations, there will be no need for guy wires and anchors and no additional right-of-way required where the transmission line changes direction. Characteristics of the transmission line are shown in Table 1. Map sheets G20-001 and G20-002 show typical deadend structures and typical tangent structures, respectively. Table 1: Transmission Line Characteristics Characteristic Value Voltage 115-kV Total length Approximately 7.7 miles Length in city of Fort Collins Approximately 0.4 miles Right-of-way width (varies with specific location and street right-of-way) Typically 75 feet wide Span between structures: typical range 400-500 feet May 2008 9