Appendix B—Transmission Line and Substation …

1 Appendix B Transmission line and Substation ComponentsPrepared by: Idaho Power Company 1221 W Idaho Street Boise, ID 83702 November 2011 Transmission line and Substation Components Appendix B November 2011 iii TABLE OF CONTENTS PROJECT FACILITIES .. 1 Transmission Structures .. 1 Types of Transmission line Support Structures .. 1 Structure and Conductor Clearances .. 8 Structure Foundations .. 8 Conductors .. 9 Other Hardware .. 10 Insulators .. 10 Grounding Systems .. 10 Minor Additional Hardware .. 11 Communication Systems .. 12 Optical Ground Wire .. 12 Communications Stations .. 12 Access Roads .. 13 21 Substation Components .. 21 Distribution Supply Lines .. 22 SYSTEM CONSTRUCTION .. 23 Land Requirements and Disturbance .. 23 Right-of-Way Width .. 23 Right-of-Way Acquisition .. 25 Land Disturbance.

2 26 Transmission line Construction .. 32 Transmission line System Roads .. 32 Soil Borings .. 34 Staging Areas .. 34 Site Preparation .. 35 Install Structure Foundations .. 35 Erect Support Structures .. 36 String Conductors, Shield Wire, and Fiber Optic Ground Wire .. 37 Cleanup and Site Reclamation .. 39 Communication System .. 39 Communication Sites .. 39 Access Road .. 39 Substation Construction .. 39 Substation Roads .. 40 Soil Borings .. 40 Clearing and Grading .. 40 Storage and Staging Yards .. 40 Grounding .. 40 Fencing .. 40 Foundation Installation .. 41 Oil Containment .. 41 Structure and Equipment Installation .. 41 Conduit and Control Cable Installation .. 42 Construction Cleanup and Landscaping .. 42 Special Construction Techniques .. 42 48 Transmission line and Substation Components Appendix B November 2011 iv Blasting.

3 42 Helicopter Use .. 44 Water Use .. 45 Construction Elements .. 45 Construction Workforce .. 46 Construction Equipment and Traffic .. 47 Removal of Facilities and Waste Disposal .. 50 Construction Schedule .. 50 SYSTEM OPERATIONS AND MAINTENANCE .. 54 Routine System Operations and Maintenance .. 54 Routine System Inspection, Maintenance, and Repair .. 54 Transmission line Maintenance .. 55 Hardware Maintenance and Repairs .. 57 Access Road and Work Area Repair .. 60 Vegetation Management .. 60 Noxious Weed Control .. 62 Substation and Communication Site Maintenance .. 62 Emergency Response .. 63 Fire Protection .. 63 DECOMMISSIONING .. 65 2021 LIST OF TABLES 22 Table 1-1. Proposed Structure Characteristics .. 8 23 Table 1-2. Foundation Excavation Dimensions .. 9 24 Table 1-3. Proposed Communications Station Locations.

4 12 25 Table 1-4. Access Road Requirements for Transmission line System .. 14 26 Table 2-1. Summary of Land Required for Construction and Operations .. 23 27 Table 2-2. Summary of Land Disturbed during Construction and Used during Permanent 28 Operations .. 26 29 Table 2-3. Miles of New and Improved off-ROW Access Roads .. 33 30 Table 2-4. Miles of New and Improved Access Roads1 .. 34 31 Table 2-5. Construction Staging Areas and Helicopter Fly Yards .. 35 32 Table 2-6. Summary of Shallow Bedrock .. 43 33 Table 2-7. Estimated Water Usage for Construction by County .. 45 34 Table 2-8. Projected Workers and Population Change during Peak Construction .. 46 35 Table 2-9. Transmission line Construction Equipment Requirements .. 47 36 Table 2-10. Equipment Requirements for Grassland and Hemingway substations .. 48 37 Table 2-11. Average and Peak Construction Traffic (per spread).

5 49 38 Table 2-12. Solid Waste Generation from Construction Activities .. 50 3940 Transmission line and Substation Components Appendix B November 2011 v LIST OF FIGURES 1 Figure 1-1. Proposed 500-kV Single Circuit Lattice Steel Structure .. 2 2 Figure 1-2. Proposed 500-kV Single Circuit Tubular Steel Pole H-frame Structure .. 3 3 Figure 1-3. Proposed 138/69-kV Double Circuit Structure with Distribution Underbuild .. 4 4 Figure 1-4. Proposed ROW Designs .. 5 5 Figure 1-5. Alternative 500-kV Single Shaft Steel Pole Structure .. 6 6 Figure 1-6. Alternative ROW Design .. 7 7 Figure 1-7. Typical Communication Site .. 13 8 Figure 1-8. Typical Road Sections for Different Terrains .. 15 9 Figure 1-9. Type 1 Drive Through Stream Crossing Methods .. 16 10 Figure 1-10. Type 2 and Type 3 Crossing Methods .. 18 11 Figure 1-11. Type 4 Channel Spanning Structures Including Fish Passage.

6 19 12 Figure 1-12. Typical 500-kV Substation .. 22 13 Figure 2-1. Disturbance Area for Tower Structures .. 29 14 Figure 2-2. Typical Disturbance Area .. 30 15 Figure 2-3. Example Access Roads and Tower Locations .. 31 16 Figure 2-4. Transmission line Construction Sequence .. 32 17 Figure 2-5. Conductor Installation .. 37 18 Figure 2-6. Project Construction Schedule .. 52 19 Figure 3-1. Live- line Maintenance Space Requirements, Single-Circuit 500-kV Lattice 20 Tower .. 59 21 Figure 3-2. Right-of-Way Vegetation Management .. 61 2223 Transmission line and Substation Components Appendix B November 2011 1 This Appendix contains detailed information provided by Idaho Power Company (IPC) regarding 1the components of the transmission system including the transmission structures, the 2communications system, and the substations . It provides details regarding construction of the 3system (Section ), goes on to provide information regarding the operations and maintenance 4of the system (Section ), and finally details the proposed abandonment and restoration 5techniques (Section ).

7 PROJECT FACILITIES 7 This section describes the various components of the transmission system for the Boardman to 8 Hemingway Transmission line Project (Boardman to Hemingway or Project), including the 9structures themselves, the conductors used, other hardware needed, the communication 10system, the access roads, and finally the substations . Both the proposed and alternative 11structures are described herein Transmission Structures Types of Transmission line Support Structures 14 The majority of the proposed transmission line circuits will be supported by steel single-circuit 15steel lattice towers. Figure 1-1 illustrates the typical tangent lattice tower structure configuration. 16In some instances, single-circuit tubular steel H-frame structures will be used where required to 17mitigate sensitive environmental resources or where land use requires shorter structure heights.

8 18 Figure 1-2 illustrates a tangent tubular steel H-frame structure. Figure 1-3 provides an 19illustration of a typical 138/68-kilovolt (kV) structure with underbuild distribution that 20would be used for approximately structures are primarily used in straight line segments and are the most common type 22of structure. Running angles are used when a transmission line changes direction up to a 23specified threshold line angle. Dead-end structures are needed for extremely long spans, when 24the line angle exceeds the threshold of a running angle tower, in highly varied terrain which can 25create uplift conditions, or when there is a need for a failure containment structure. Angle and 26dead-end structures are heavier and require larger foundations. 27 Figure 1-4 illustrates the right-of-way (ROW) design configurations for proposed structures. 28291 Of the miles, miles would be a 138-kV single-circuit which because of its limited extent, is not further discussed in thisdocument.

9 Transmission line and Substation Components Appendix B November 2011 2 1 Figure 1-1. Proposed 500-kV Single Circuit Lattice Steel Structure 23 Transmission line and Substation Components Appendix B November 2011 3 1 Figure 1-2. Proposed 500-kV Single Circuit Tubular Steel Pole H-frame Structure23 Transmission line and Substation Components Appendix B November 2011 4 12 Figure 1-3. Proposed 138/69-kV Double Circuit Structure with Distribution 3 Underbuild4 Transmission line and Substation Components Appendix B November 2011 5 1 Figure 1-4. Proposed ROW Designs 23 Transmission line and Substation Components Appendix B November 2011 6 Figure 1-5 presents the configuration of the alternative 500-kV monopole structure which could 1be used in active agricultural areas where location is critical to farming operations. Figure 1-6 2illustrates the alternative ROW design configuration.

10 34 Figure 1-5. Alternative 500-kV Single Shaft Steel Pole Structure 5 Transmission line and Substation Components Appendix B November 2011 7 1 Figure 1-6. Alternative ROW Design Proposed 500-kV Single Circuit Galvanized Lattice Steel Structures 4 Lattice steel towers will be fabricated with galvanized steel members treated to produce a dulled 5galvanized finish. The average distance between 500-kV towers will be 1,200 to 1,300 feet. 6 Structure heights will vary depending on terrain and the requirement to maintain minimum 7conductor clearances from ground. The 500-kV single-circuit towers will vary in height from 110 8to 195 feet. Proposed 500-kV Single Circuit Tubular Steel H-Frame Structures 10 The 500-kV H-frame structures will be fabricated with self-weathering tubular steel treated to 11produce a rust-like finish. The average distance between 500-kV H-frames will be 1,200 to 121,300 feet.