Environmental Assis for Orono Substation Expansion

Home Browse Search

Special construction techniques to minimize impacts to environmentally sensitive areas, such as wetlands, are discussed in Section 5.0 of this document. Xcel Energy indicates in its route permit application that environmentally sensitive areas and wetland areas may require special construction techniques beyond what is described above. 4.3 Conductors Once the structures have been erected, conductors and shield wires are installed by establishing stringing setup areas within the right-of-way. Stringing operations require brief access to each structure to secure the conductors wire to the insulators or the shield wire to shield wire clamps once final sag is established. These stringing setup areas are typically located every two miles along the project right-of-way. The wires are pulled with a rope lead that connects to every structure through a dolly attached at the insulator/clamp location. Temporary guard or clearance poles are installed at crossings to provide adequate clearance over other utilities, streets, roads, highways, railroads, or other obstructions. Necessary notifications are made or permit requirements are followed, to mitigate any concerns with traffic flow or operations of other utilities. 4.4 Orono Substation Replacement of the existing 69 kV Orono Substation with an expanded 115 kV Orono Substation would take place in the southwest portion of the 16 acre parcel owned by Xcel Energy. The site of the expanded 115 substation will encompass the existing 69kV site. No additional land would need to be acquired or rights-of-way obtained for the proposed substation work. A schematic of the replacement substation is included in Appendix B, Figure B-5. Xcel Energy will grade a total area of approximately 1.6 acres, for the substation and re -aligned access road to ensure both a stable base for the substation equipment and proper drainage and runoff control (Xcel Energy, personal communication, October 31, 2011). Based on preliminary grading plans for the substation site, Xcel Energy estimates that grading would require approximately 15,700 cubic yards of cut and, depending upon the dimensions of a berm that may be constructed at the substation site, between 3,800 and 6,100 cubic yards of fill (Xcel Energy, personal communication, November 18, 2011). A stormwater pond will be installed in accordance with the Stormwater Pollution Prevention Plan (SWPP) prepared for the Project. During grading, the driveway will also be rerouted to end at the entrance to the replacement substation. Following grading a perimeter fence would be installed to contain the substation equipment. After installation of the fence, concrete foundations would be placed to support the substation equipment and gravel laid throughout the fenced area. After the surface area is prepared, substation components would be delivered on tractor -trailer trucks and installed on their foundations. The termination structure for Great River Energy's 69 kV transmission line will be removed, but switchgear from the existing 69 kV substation will be reused in the replacement substation. During construction a mobile substation will be installed to ensure that service is maintained until the 115 W source is energized. Transmission facilities at the replacement Orono Substation will consist of- * £• Anew 115-13.8 kV substation with a 28 mega volt ampere (MVA, 118-14.3 transformer; Environmental Assessment PUC Docket E002/TL-11-223 Page 17