underground feasibility study - xcel energy...underground cable system. a critical factor of the...

POWER ENGINEERS, INC.

STL 085-2544 (SR-02) PAWNEE-DANIELS PARK REV 2 (02/14/2014) RP 131199

February 14, 2014

XCEL ENERGY

Pawnee to Daniels Park

345 kV Project Underground Feasibility Study

PROJECT NUMBER: 131199

PROJECT CONTACT: LES HINZMAN RYAN PARKER EMAIL: [email protected] [email protected] PHONE: 1-208-788-0577 1-314-851-4091


STL 085-2544 (SR-02) PAWNEE-DANIELS PARK REV 2 (02/14/2014) RP 131199

Underground Report

PREPARED FOR: XCEL ENERGY PREPARED BY: RYAN PARKER

(314) 851-4091 [email protected]

LES HINZMAN (208) 788-0577

[email protected]

REVISION HISTORY

DATE REVISED BY REVISION

10/08/13 1st Draft Issued for Review

11/06/13 Ryan Parker Issued as Final

2/14/14 Ryan Parker Issued as Final


STL 085-2544 (SR-02) PAWNEE-DANIELS PARK REV 2 (02/14/2014) RP 131199 PAGE i

TABLE OF CONTENTS

0.0 EXECUTIVE SUMMARY ...................................................................................................... 1

1.0 PROJECT DESCRIPTION ..................................................................................................... 2

1.1 XLPE CABLE SYSTEM DESIGN ............................................................................................... 2 1.1.1 System Description and Trench Design ......................................................................... 2

1.2 AMPACITY STUDIES ................................................................................................................ 4 1.2.1 Ampacity Calculations ................................................................................................... 4

1.3 ELECTROMAGNETIC FIELDS ................................................................................................... 5

2.0 UNDERGROUND CABLE SYSTEMS .................................................................................. 7

2.1 RELIABILITY OF 345 KV CABLE SYSTEMS ............................................................................. 7 2.2 EXTRUDED DIELECTRIC CABLE SYSTEMS .............................................................................. 7

2.2.1 Cable ............................................................................................................................... 7 2.2.2 Cable Accessories ........................................................................................................... 9 2.3.3 Civil Installation ............................................................................................................. 9 2.3.4 Vault Design and Installation ....................................................................................... 10 2.3.5 Cable Maintenance and Repair ..................................................................................... 11 2.3.6 Pros and Cons ............................................................................................................... 11

2.5 TRENCHLESS INSTALLATIONS .............................................................................................. 12

3.0 TERMINATIONS .................................................................................................................. 13

3.1 DESCRIPTION ........................................................................................................................ 13 3.1.1 Termination Structure ................................................................................................... 13 3.1.2 Transition Station ......................................................................................................... 13

4.0 COST ESTIMATE ................................................................................................................. 14

4.1 COST ESTIMATE ASSUMPTIONS ............................................................................................ 14 4.2 SUMMARY OF COST ESTIMATES ........................................................................................... 15

5.0 COMPARISON OF ENVIRONMENTAL IMPACTS OF OVERHEAD AND UNDERGROUND TRANSMISSION LINE CONSTRUCTION .................................................. 17

5.1 RIGHT OF WAY WIDTHS ....................................................................................................... 17 5.2 GROUND DISTURBANCE ....................................................................................................... 17 5.3 LAND USE AND AESTHETICS ................................................................................................ 18 5.4 ELECTRIC FIELDS, MAGNETIC FIELDS, AND NOISE .............................................................. 18 5.5 RIGHT OF WAY CLEARING AND VEGETATION CONTROL ..................................................... 18 5.6 EROSION CONTROL IN UNSTABLE AREAS ............................................................................ 19


STL 085-2544 (SR-02) PAWNEE-DANIELS PARK REV 2 (02/14/2014) RP 131199 PAGE ii

APPENDICES

APPENDIX A – AERIAL MAP

APPENDIX B – AMPACITY STUDIES

APPENDIX C – EMF CALCULATIONS

APPENDIX D – TRENCH DETAILS

APPENDIX E – VAULT DETAILS

APPENDIX F – COST ESTIMATES


STL 085-2544 (SR-02) PAWNEE-DANIELS PARK REV 2 (02/14/2014) RP 131199 PAGE 1

0.0 EXECUTIVE SUMMARY Xcel Energy (Xcel) is evaluating the feasibility of undergrounding portions of a new double circuit 345 kV transmission line to be located southeast of Denver, Colorado. The proposed hybrid overhead and underground 345 kV circuits would serve as inner transmission tie lines for the existing 345 kV transmission ring around Denver. Several substations would be included in this scenario; however, the interconnection of Sulphur Substation to IREA Parker Substation is the primary candidate being considered for an underground installation due to urban congestion. As part of this evaluation, Xcel has requested that POWER Engineers, Inc. (POWER) evaluate the associated costs and technical feasibility for installing new extruded dielectric cables within a manhole and duct bank system in the existing overhead transmission easement between Sulphur and IREA Parker substations. An additional estimate will also be included for a typical 1-mile underground cable installation in a developed residential area within the 210-foot easement. POWER performed ampacity calculations for various underground line configurations to estimate preliminary cable sizing requirements for this installation. Based on these calculations, POWER concluded that three cables per phase would meet the 1,733 MVA rating requirement for the new 345 kV lines. Only the XLPE cable system was evaluated for these underground transmission lines. The estimated installation costs for the XLPE insulated cable systems for the transmission lines from Sulphur Substation to IREA Parker Substation and the typical 1-mile 345 kV underground lines through a developed residential area are as follows.

Description Length (miles)

Material Labor Other* Total

Sulphur Substation to IREA Parker

1.4 $25,371,514 $10,668,513 $14,714,989 $50,755,016

1-mile Developed Residential Installation 1 $15,439,563 $6,283,513 $8,813,243 $30,536,318

Table 0-1: Cost Summary

* Other costs include additional expenditures for contingencies, overheads, AFUDC, escalation, etc.



1.0 PROJECT DESCRIPTION POWER Engineers, Inc. (POWER) prepared this report for Xcel’s Pawnee to Daniels Park 345 kV Project. The ampacity requirement for each circuit is 2,900 A (1,733 MVA at 345 kV). Ampacity calculations were performed to estimate the cable conductor size required to reach the desired ampacity. The results are discussed in Section 1.2 of this report. Electromagnetic field (EMF) calculations were completed based on the probable loading of the cables to determine the EMF intensity of the proposed system. These results are discussed in Section 1.3 of this report. This report describes and summarizes:

Preliminary cable system design options; Cost estimates for the two pre-selected routes; and Environmental effect of overhead and underground construction

Appendix A contains an aerial route map for the underground transmission lines to be considered Appendix B contains ampacity studies Appendix C contains EMF calculations Appendix D contains typical trench details Appendix E contains termination and vault details Appendix F contains cost estimates for the procurement and installation of the cable system 1.1 XLPE Cable System Design POWER reviewed two duct bank configurations for the proposed installation to include placing both circuits in the same duct bank and installing each circuit in a separate duct bank. Due to the large ampacity requirement for each circuit, it was determined that the most cost effective and practical design would be to install each circuit in its own duct bank and trench. Based on the results of the ampacity study, an underground 345 kV XLPE cable system would consist of three cables per phase for each circuit. The cable would utilize a 3500 kcmil segmented copper conductor with one cable installed in an individual duct. A minimum of 20 feet would be required between the duct banks of each circuit to eliminate mutual heating impacts between the two circuits. A general discussion of XLPE cable systems and installation methods is provided in Section 2. 1.1.1 System Description and Trench Design Both routes selected for this study share the same trench design. For each circuit, the cable system would consist of three cables per phase, installed within polyvinyl chloride (PVC) conduits encased in a 4 feet H x 5 feet W concrete duct bank. The concrete would have a compressive strength of 3000 psi. The duct bank would consist of multiple conduits for the XLPE transmission line cables, the



grounding cables, and the fiber-optic cables. The duct bank would be installed at a minimum 36 inches cover depth. The cable system and trench details are as follows:

High Voltage, Extruded Dielectric Cable o 3500 kcmil segmented copper o Extruded cross-linked polyethylene solid dielectric insulation o Lead, aluminum, or copper sheath to serve as the cable shield and metallic moisture

barrier o Protective jacket

Open Cut Trenching o Mechanical excavation of concrete/asphalt (for roadways), top soil or sub-grade

material o 3 cables per phase duct banks

Two (2) ductbanks separated by 20 feet edge to edge Approximate individual dimensions of 4 feet tall by 5 feet wide Minimum depth below grade of 36 inches Concrete encased ductbank

Twelve (12) eight-inch (8”) PVC conduits for the power cables Three (3) 2” PVC conduits for ground continuity conductors One (1) two-inch (2”) PVC conduit for temperature monitoring Two (2) four-inch (4”) PVC conduits for communications

o Splicing manholes Approximate dimensions are 8 feet wide by 30 feet long by 8 feet tall Pre-cast design Premolded cable splices

Trenchless Designs (1.4 mile route only) o Jack and bore required under Highway 83 o One bore per circuit

Length: 200 feet Depth: 20 feet Casing: 54 inch HOBAS ®

Cable Terminations o Steel structures and concrete foundations at each substation o 18 terminations and 18 arresters o Grounding system for each structure

System Communications and Monitoring o Fiber optic communication cables o Fiber optic temperature monitoring system for cable

The final duct bank size and layout would be determined during detailed design and would be based on Xcel’s completed design criteria. Factors to be considered during detailed design are electrical requirements, heat dissipation, minimal burial depths, existing facility/utility locations, and cable installation requirements. Drawing D-1 in Appendix D shows a typical trench cross section for an XLPE duct bank configuration.



1.2 Ampacity Studies POWER performed preliminary cable ampacity calculations for the XLPE cable system. The primary purpose of the ampacity calculations was to determine a minimum conductor size, number of cables and cable system configuration based on the design requirements provided by Xcel Energy. 1.2.1 Ampacity Calculations POWER used CYME International’s Cable Ampacity Program (CAP) to model each of the cable systems. Each cable system was analyzed using the following design criteria.

Voltage 345 kV Ampacity

Normal (Continuous) 2900 Amps (1,733 MVA) at 345 kV Load Factor 75% Burial Depth 10-ft max (Residential Construction)

20-ft max (Bore Depth) Thermal Resistivity (ρ, rho)

Native Soil 90°C-cm/W Encasement/Corrective Backfill 50°C-cm/W at 5% moisture Thermal Grout 70°C-cm/W

Ambient Temperature Earth 18°C at 10-ft depth 11°C at 20-ft depth

Maximum Conductor Operating Temperature XLPE 90°C Steady State 105°C Emergency Many factors should be considered when trying to design the optimal and most economical underground cable system. A critical factor of the underground cable system is the thermal performance. Among those design parameters that must be determined to achieve optimal thermal performance and with it maximum load transfer are:

Cable Size – increasing the conductor size generally allows for an increased load transfer capability. However, there is a limit to the maximum conductor size that can be manufactured by the majority of cable suppliers. This conductor size is typically accepted to be 3000 to 3500 kcmil, although larger conductor sizes could be manufactured at a significant increase in cost.

Soil Thermal Resistivity – the ability to dissipate heat away from the cable is based

on the thermal properties the native soils and the backfill material installed around the cable duct.

Cable Depth – the deeper the cable is from grade, the harder it is for the surrounding

soil to dissipate the heat, thus resulting in a lower ampacity.



Cable Separation – other energized cables in close proximity also generate heat, thus resulting in mutual heating. Mutual heating could be reduced further by increasing the separation of the cables. However, the further the cables are separated, the larger the excavation, backfill material quantities, as well as labor, resulting in an overall increase in project costs.

Ampacity calculations were performed for two scenarios to determine the minimum conductor size and cable system configuration. “Pinch points”, key positions along the route that would limit the cable ampacity, were identified and used to compare the thermal effects between the duct bank designs. The trenchless crossing under Highway 83 (assumed at 20 feet) and a typical utility crossing (approximate trench depth of 10 feet) represented the pinch points for the underground transmission line in this study. For depths greater than 20 feet, each of the factors described above would have to be considered, and in all cases, the resulting installation would likely cost more. The results of the ampacity calculations for the proposed two 345 kV circuits are provided below. The cable system type, number of cables per phase, installation depth, and resultant ampacity is noted. The calculations assume a minimum separation of 20 feet between the edges of the duct banks to eliminate the effects of mutual heating between the two circuits.

Table 1-1: Ampacity Results

Ampacity calculations are in Appendix B. Typical trench depth assumes a minimum of 36 inches of cover over the duct bank. Trench detail configurations are shown in Appendix D. 1.3 Electromagnetic Fields A common concern with the operation of transmission lines is the magnitude of the electromagnetic fields produced by the EHV underground cable system. Electromagnetic fields are made up of two components – electric fields and magnetic fields. Electric fields are produced by electric potential or voltage. Electric fields for underground cables are generally not a concern, because they are completely contained within the transmission cable by the metallic shield. Magnetic fields are produced by the flow of AC electric current. Magnetic fields are measured in Gauss (G) or Tesla (T). The results for this study are shown in milligauss (mG).

Description Conductor Size Cables per

Phase

345 kV Insulation

Type

Burial Depth

(ft)

Total Ampacity

(A) Highway 83

Crossing 3500 kcmil 3 XLPE 20 2931

Typical Ductbank 3500 kcmil 3 XLPE 10 3570



Any device that produces a voltage and carries electric current will produce EMF. EMF produced by underground transmission lines will have the greatest magnitude when measured directly above the circuit, and the levels will diminish as the distance increases away from the circuit. Values listed in Table 1-2 are the calculated EMF values directly above a single circuit transmission line. These values are calculated at 1 meter (3.28 feet) above the ground (grade), centered over the circuit. POWER used CYME International’s EMF calculation module to model the electromagnetic field effects of the XLPE insulated cable system. Calculations were perpared for each cable system based on public utility commission (PUC) levels for the transmission circuit.

The underground calculations were based on the following general criteria.

Distance above ground for calculations 3.28 feet (1.0 meter)

Burial depth 3 feet

Transmission currents are balanced (equal magnitude on each phase of the circuit and the three phases are separated by 120 degrees)

Electrical loading values provided by Xcel

Proposed Loading XLPE (mG) at 1.0 m above ground directly above the cable

Typical Loading 433 MVA 26.8 Max Conductor Loading 866 MVA 53.6 Max Circuit Loading 1733 MVA 107.0

Table 1-2 EMF Table

EMF calculations can be found in Appendix C.



2.0 UNDERGROUND CABLE SYSTEMS There are currently two common types of cable systems being utilized at the 345 kV voltage level, high-pressure fluid-filled (HPFF) and cross-linked polyethylene (XLPE). As stated in the Project Description in Section 1, only the XLPE underground cable systems will be considered for the 345 kV underground transmission lines for Xcel’s Pawnee to Daniels Park Project. In this section, a description of the XLPE cable system is presented. 2.1 Reliability of 345 kV Cable Systems In general, underground transmission cable systems are very reliable. The main reliability issue with an underground cable circuit compared to an overhead circuit is the length of the outage in the event of a circuit fault. With an overhead circuit, the line can generally be placed back into service in a relatively short amount of time, typically less than a day, thus increasing the circuit’s availability for transmitting load. When there is a fault on an underground line, the line may be out of services for a significant amount of time, more than two weeks and up to 6 months, depending on the type of failure and how quickly it can be located and repaired. Because of these longer outage durations, an underground circuit has a lower circuit availability as compared to an equivalent overhead circuit. One common design practice used to alleviate this problem is to have an alternative transmission line or 100% redundancy. By implementing a design to ensure continuous operation, the availability of underground transmission lines increases significantly. Another design practice is to use multiple cables for each of the 3 phases. This design has 3 cables/phase. If one cable fails, it can be removed in several days. The circuit availability would then be about 2/3 of the maximum line rating. 2.2 Extruded Dielectric Cable Systems 2.2.1 Cable The components of a typical XLPE cable are shown in Figure 2-1. The typical cable consists of a stranded copper or aluminum conductor, inner semi-conducting conductor shield, extruded solid dielectric insulation, outer semi-conducting shield, metallic moisture barrier, and protective jacket. Insulation materials used for solid dielectric cables include:

Thermoplastic Polyethylene (PE) Compounds

Typical thermoplastic polyethylene insulation materials are low-density polyethylene (LDPE), high molecular weight polyethylene (HMWPE) and high-density polyethylene (HDPE).

Thermosetting Compounds

Ethylene propylene rubber (EPR) and cross-linked polyethylene (XLPE) are typical thermosetting insulation compounds.



Materials used for semi-conducting extruded conductor and insulation shields are semi-conducting PE, XLPE, and EPR compounds. PE compounds are used with PE and XLPE insulation, XLPE compounds with XLPE insulation, and EPR compounds with EPR insulation. Cable jackets are typically extruded PE, and on rare occasions, polyvinyl chloride (PVC).

Figure 2-1: Typical Extruded Dielectric Cable Cross-Section

The manufacturing process for extruded cables is of critical importance to ensure a dependable end product. Triple extrusion, using the “true triple head” technique, is the preferred and recommended process of constructing the cable layers, which most manufacturers practice today. Because microscopic voids and contaminants lead directly to cable failures, quality control during manufacture of extruded dielectric cables is critical to minimize moisture contamination, voids, contaminants, and protrusions. In conjunction with the triple extrusion process, manufacturers minimize insulation contamination by using super clean insulation compounds, transported and stored in sealed facilities, while screening out all other contaminants at the extruder head.

1 – CONDUCTOR Material: copper

2 – INNER SEMI-CONDUCTIVE SHIELD 3 – EXTRUDED SOLID DIELECTRIC INSULATION

Material: cross-linked polyethylene

4 – OUTER SEMI-CONDUCTIVE SHIELD 5 – SEMI CONDUCTIVE SWELLING/BEDDING

TAPES 6 – CONCENTRIC COPPER WIRE METALLIC

SHIELD 7 – SEMI CONDUCTIVE SWELLING/BEDDING

TAPES 8 – MOISTURE BARRIER

Material: copper, aluminum, lead, or stainless steel

9 – PROTECTIVE JACKET



2.2.2 Cable Accessories The three basic cable accessories for extruded dielectric cables are splices, terminations, and sheath bonding materials. Pre-fabricated or pre-molded splices are commonly used to joint extruded dielectric cables and are recommended for a 345 kV XLPE cable system. Cable preparation for these types of splices is generally the same. Insulation and shields are removed from the conductor, and the insulation is penciled. The conductor ends are then joined by a compression splice or metal inert gas (MIG) welding (aluminum conductor only). An advantage of these types of splices is that all parts can be factory tested prior to field installation. Terminations are available for extruded dielectric cable to allow transitions to overhead lines or above ground equipment. Termination bodies are typically made of porcelain or polymer and include skirts to minimize the probability of external flashovers due to contamination. Another important component of an XLPE cable system is the grounding/bonding of the cable shield. Unlike an underground distribution system, in which the shield is grounded at each splice and termination, an underground transmission line requires alternative grounding/bonding methods. Grounding at each splice and termination causes circulating currents on the cable shield resulting in additional heating in the cable and lower ampacity. The way to maximize the ampacity of an underground cable is to eliminate the circulating currents. This is accomplished with underground transmission cables by using special bonding methods such as single-point and cross-bonding. These methods eliminate or reduce the amount of current that would flow on the cable shield, resulting in no or limited additional heating and ultimately a higher ampacity. When using one of these specialized bonding techniques, additional equipment (link box) needs to be installed in the cable vaults (manholes) and at the terminal ends. A link box allows the cable shield to be connected to ground, a surge diverter, or an adjacent cable shield. The final connection depends on the bonding scheme used. The link box also allows the cable shields to be isolated for routine jacket testing purposes. 2.3.3 Civil Installation There are two common types of XLPE cable system installation. They are direct buried and concrete encased duct banks. Even though direct buried is the most economical method for installing an XLPE cable system, the most common method in the U.S. is to install a concrete encased duct bank system. The reasons a duct bank system is the preferred method are:

Provides better mechanical protection than direct buried cable. Eliminates re-excavation in the event of a cable failure. Allows for opening short lengths of trench for construction activities versus the direct buried

system, which requires that the entire trench be left open for cable installation. The most basic method for constructing an underground duct bank is by open cut trenching. Typical construction results in the use of mechanical excavation to remove the concrete, asphalt road surface, topsoil and sub-grade material to the desired depth. Removed material is relocated to an appropriate off-site location for disposal, or occasionally reused as backfill. Once a portion of the trench is



opened, PVC conduit is assembled and lowered into the trench. The area around the conduit is filled with a high strength thermal concrete (3000 psi). After the concrete is installed, the trench is backfilled, generally with a soil capable of thermal correction, and the site restored. Backfill materials should be clean excavated material, thermal sand and/or a thermal concrete mix. 2.3.4 Vault Design and Installation Access vaults are needed periodically along an underground route to facilitate cable installation, for maintenance requirements, and for access for future repairs. Vaults are typically spaced every 1,500 to 2,000 feet along the route for XLPE cable systems. The vault size and layout is based on the type of cable system installed. For an XLPE cable, the vault size is determined based on the space required for cable pulling, splicing, and supporting the cable in the vault. The standard size of each vault would be about 8 ft wide by 28 ft long. For this project, a vault would be needed for each set of cables, due to the number of bends in the route and the requirement of needing multiple cables per phase to achieve the load requirement. Placing each set of cables in separate vaults also allows Xcel to perform maintenance or repair on one set of cables while keeping the other energized, and operating the circuit at a reduced line rating. The factors contributing to the final placement of the vaults are allowable pulling tensions, sidewall pressure on the cable as it goes around a bend, and the maximum length of cable that can be transported on a reel. The amount of cable that can be transported on a reel is based on the reel’s width, height, and weight. A typical pre-cast vault layout and configuration is shown in Appendix D.



Figure 2-2: Typical XLPE Vault Installation

2.3.5 Cable Maintenance and Repair XLPE cable requires little maintenance since it is usually installed in a duct bank. Duct inspections are performed in conjunction with routine vault inspections. Furthermore, ducts are seldom cleaned unless a new circuit or grounding is being installed. Unless environmental conditions dictate more inspections, a yearly vault inspection is generally sufficient to examine the cable sheaths, protective jackets, joint casings, cable neutrals, and general physical condition of the vault. Terminations should also be visually checked on a yearly basis to ensure a properly operating system. Performing these inspections on a one-mile segment should take less than one week for a utility crew to perform. In the unlikely event of an electrical fault, the cable failure must be located. This requires specialized equipment as well as a knowledgeable crew to pinpoint the failure. The time it takes to locate the fault location depends largely on the environmental surroundings and access to the cable for testing. Once pinpointed, an entire section of cable can be removed and replaced between vault sections, or the duct bank can be opened up and an experienced splicing crew can rejoin the cable ends. The amount of time the system is down depends entirely on the fault location and the repair method that provides the most advantageous solution. Typical repair time can range from two to four weeks. 2.3.6 Advantages and Disadvantages The pros and cons of XLPE cable systems for use in high voltage applications are:



Advantages: Essentially no operation and maintenance requirements Appropriate reliability reported for systems of modern design at voltages of 230 kV and below in

Japan, the U.S. and European countries. Extensive use and success at 400 kV in France and Japan Higher normal operating and short circuit temperature ratings as compared to HPFF systems Installation environmental condition requirements for splicing and terminating are less stringent Shorter time required for repair Dielectric losses for extruded cable systems considerably less than paper insulated cable systems Less specialized installation equipment required Disadvantages: Susceptible to damage from dig-ins, if direct buried Potential for induced sheath voltages and losses Trench for installation of entire cable length (direct buried) must be left open during cable

installation Duct bank/conduit installation reduces thermal performance and increases cost XLPE insulation not forgiving Limited splicing/terminating workforce in U.S 2.5 Trenchless Installations Trenchless civil installation techniques have been developed for crossing environmentally sensitive areas and major obstructions such as waterways, wetlands, highways, and railroads. Three trenchless methods have commonly been used for installing underground transmission facilities. These methods are:

Jack and Bore Horizontal Directional Drilling Micro-tunneling

For the 1.4 mile 345 kV underground installation from IREA Parker to Sulphur Springs Substation, it is assumed that there would be a required trenchless installation to cross beneath Highway 83. The jack and bore method would be used to cross under Highway 83 between the two substations; separate borings would be performed for each 345 kV circuit. The required borings were estimated using a 54-inch HOBAS pipe casing at a depth of 20-feet below grade on the eastern side of Highway 83. The anticipated depth of the bore was determined based on the significant elevation change from the east side of the highway to the west. Further analysis and conceptual design work would be required to perform a cable system study for incorporating any additional trenchless installations.



3.0 TERMINATIONS The XLPE underground transmission circuits would require the construction of termination structures at the end of each underground segment. Structures would support cable terminations, lightning arresters, and dead-end hardware for overhead conductors. This would be to transition the circuits from underground to overhead. For XLPE systems, fenced transition stations would be required if the utility required switching and monitoring capability. In addition, transition stations would be required if reactive compensation were needed at the specific transition end of the cable. Detailed reactive compensation studies would be required to determine whether compensation would be required. Those studies are not in the scope of this report. 3.1 Description Typical termination stations have a footprint of approximately 250 ft by 400 ft. However, this may be a benefit as a number of different switching arrangements can be attained, as well as the addition of circuit protection, monitoring, and voltage regulation. Most transition stations house an A-frame style dead end structure with pedestal style termination structures. The XLPE system can be converted to an overhead line in a much simpler fashion with the use of a termination structure, because the underground cables, as well as all of the required terminations, can be attached directly to the structure. This has been done at 115 kV and 230 kV on the Xcel system. At 345 kV, no stand-alone termination structure has been installed in the US. This structure is not acceptable. For this installation, Xcel required switching and monitoring at the cable ends, so transition stations would still be required. The Advantages and Disadvantages of each configuration are: 3.1.1 Termination Structure

Advantages: Disadvantages: Essentially no operation and maintenance

requirements. High reliability Small structural footprint Terminations can be located on structure Lower installation cost

Can only be used for 115 kV and 230 kV XLPE cable

Failure of structure may result in prolonged outage

3.1.2 Transition Station

Advantages: Disadvantages: More switching capabilities Increased protection capabilities/schemes SCADA can be installed in the station Voltage regulation, if required can be incorporated Fault Location Available

Larger structural footprint Higher cost Higher maintenance costs



4.0 COST ESTIMATE The cost estimate for the underground cable system was prepared using budgetary quotations from high voltage cable manufacturers, contractors familiar with the installation and operation of high voltage underground cable systems, and recent underground projects similar in nature. There are several factors that can influence the cost of an underground system. These factors commonly are:

Cost of material Contractor/manufacturer’s availability Cable system location Subsurface conditions: The type and depth of soil and rock that must be excavated to place

the cable can dramatically affect the cost. For example, construction costs in rock formations are significantly higher than construction costs in clay soils. The presence of existing underground facilities also presents a significant uncertainty when estimating the cost of an underground project.

4.1 Cost Estimate Assumptions

1) Materials used in the cost estimates meet all applicable industry standards.

2) Construction would be performed by qualified craftsmen experienced in installing high voltage XLPE underground transmission systems.

3) Due to the volatility of material costs, these estimates are subject to market fluctuations. The cable costs reflect a copper index of $3.32/lb

4) Costs to obtain all environmental, local, state, and federal permits and mitigation as required are not included.

5) Costs to obtain all necessary right-of-way, easement, and property outside the limits of Xcel as required are not included.

6) No spare cable or accessories were included in the estimates.

7) Single point bonding of XLPE cable sheaths was assumed.

8) Mobilization and Demobilization costs were not included for the 1-mile typical underground installation in a developed residential area cost estimate.

9) Costs for Dewatering were not included in the estimates.

10) Rock excavation costs were not included in the cost estimates. If rock is encountered, costs in Table 4-1 could increase as much as 10%.

11) An overall 15% contingency was included in the cost estimates.

12) The estimates do not include termination structures or foundations.

13) The 1 mile estimate does not contain any costs associated with terminal ends of the cable.

14) The 1.4-mile estimate does not contain any equipment (including arresters) costs on the terminal end of the cable except terminations.



15) A system study would need to be conducted to determine the detailed engineering and construction requirements for reactive compensation. A study could cost from $150,000 to $300,000. For this report, reactors are not included in the cost estimate.

4.2 Summary of Cost Estimates A summary of the costs for the cable investigated has been included in Table 4-1 below. This includes termination structures, but not transition stations.

Description Length (miles)

Material Labor Other Total


1.4 $25,371,514 $10,668,513 $14,714,989 $50,755,016

1-mile Developed Residential Installation

1 $15,439,563 $6,283,513 $8,813,243 $30,536,318

Table 4-1: Cost Summary* Table, Excluding Transition Stations

4.3 Schedule There are four main parts to the project schedule: engineering design and completion of construction documents, material procurement, civil construction and electrical construction. The timeline for engineering design and completion of construction documents is primarily a function of route length and complexity of the route alignment (terrain, road construction, trenchless construction, etc). Material procurement is based on how quickly suppliers can supply the construction materials needed. Long lead-time items are cable and accessories, transition/termination structures and manholes. The civil construction is dependent upon a number of things such as: number of crews being utilized for installation, type of construction (rural, urban, etc) and type of installation (trench vs. trenchless). Number of pulling and splicing crews is the principal variable in electrical construction. Major assumptions made for high level conceptual timelines are:

Durations are based on a linear approach to construction. If multiple resources (contractors, crews, etc) are utilized, the overall project schedule could be reduced significantly.

Engineering, procurement, and construction activities could overlap as appropriate to reduce total project schedule. For instance,

o Materials could be procured once the majority of engineering is complete. o Electrical construction could begin after a good portion of civil construction is

complete. Electrical construction consists of a cable pulling crew and splicing crew. Splicing would

follow behind the pulling crew and begin after the first few sections of cable are installed.



4.4 Summary of Schedule The durations for engineering, procurement, and construction activities required for each option are shown in Table 4-2 below.

Route ROW Total Length (miles)

Engineering Design (months)

Material Procurement (months)

Civil Construction (months)

Electrical Construction (months)


1.4 6 10-12 9 12

Developed Residential Underground

1 6 10-12 8 10 Table 4-2 Schedule Summaries



5.0 COMPARISON OF ENVIRONMENTAL IMPACTS OF OVERHEAD AND UNDERGROUND TRANSMISSION LINE CONSTRUCTION The environmental impact of underground transmission line construction differs substantially from overhead transmission. Different right of way/easement requirements would also apply depending on the type of underground cable system installed. A separation between the two circuits means that they could be installed on either combined or separate right of ways. Temporary easements may be required if the construction activities expand beyond existing rights of way, or if there is insufficient room available for the set up of the installation equipment. 5.1 Right of Way Widths Underground right of way widths can be limited to the area containing the cable system with buffer area on each side of the centerline, which would serve as additional protection from unintentional excavation damage as well as to provide access for maintenance activities. Typically, a cable system of this magnitude would require a combined 55-foot permanent easement when crossing private land using open trenching techniques. This would allow the two circuits to be installed a minimum of 10 feet from each right of way edge, and still maintain a separation of 20 feet from the edge of each duct bank. Xcel has an existing easement 210 feet in width that would be used for the installation of a double circuit 345 kV cable system. Although there is also existing double circuit 230 kV overhead transmission infrastructure within this easement, there remains sufficient room to construct the underground lines. 5.2 Ground Disturbance Most ground disturbance during overhead construction occurs at the structure locations. Underground construction involves extensive ground disturbance including trenching along the entire line length and the installation of splicing and pull-through vaults as necessary. Sensitive features such as streams, rivers, and wetlands may exist in the line route. While overhead construction has the flexibility to span many such features, underground construction does not. Underground transmission line installation requires construction through these sensitive features as they are crossed by the line route. Directional drilling or boring may be required for underground construction in order to minimize impacts to streams, rivers, and wetlands. However, where directional drilling is not feasible, trenching through sensitive areas may be required for underground construction. Underground construction requires extensive coordination with other underground utilities to avoid damage during construction. This level of coordination usually exceeds that necessary for overhead construction. The potential to disrupt or damage underground utilities is almost always greater with underground construction.



Replacement or restoration activities may mean additional ground disturbance for underground lines. Overhead repair work usually involves light impact at the structure locations. Secondary off-site ground-disturbing impacts may be required for underground lines if selective fill is required for thermal mitigation. The source sites for these thermal backfills are excavated to obtain this select fill material. 5.3 Land Use and Aesthetics Overhead construction can be considered intrusive in visually sensitive environments. Urban underground construction, if properly rehabilitated, typically has lower visual impacts than overhead construction. However, in rural areas underground routes are not without visual impacts due to the clearing required for the corridor. Overhead construction may not be suitable for congested urban areas and generally impact urban land use more than underground construction. In rural settings, underground construction can be much more disruptive to agricultural or rural land uses than overhead construction. Underground construction would require that disturbed vegetated areas be restored to preconstruction conditions, however, large trees would not be allowed within 15 feet of the duct bank. Traditional farming operations are usually permitted along the underground route. Underground vaults would require the same separation guidelines as an overhead structure foundation. 5.4 Electric Fields, Magnetic Fields, and Noise Underground construction in pipes or shielded cable eliminates electrical fields at the right of way boundary. Magnetic fields are generally higher directly over an underground installation when compared to an overhead installation due to the relative close proximity of the conductor, although magnetic fields tend to decrease more rapidly with distance for underground installations as compared to overhead. Details of the underground magnetic field calculations can be found in Section 2.0 and in Appendix B. Overhead lines can emit a hiss or low hum due to corona discharge during rainstorms or humid periods. Underground lines are silent for the most part, with the exception of the immediate area near termination points. 5.5 Right of Way Clearing and Vegetation Control In undeveloped areas, underground construction requires the right of way, both temporary and permanent easements, to be totally cleared to allow for construction and the establishment of the right of way. This includes trees, brush, and ground cover. While low growing vegetation can be reestablished over an underground installation, trees or plants with woody roots should not be allowed to grow over the line. Overhead construction typically requires complete clearing only in the area of the structures and removal of trees along the line route to provide for electrical clearance and maintenance. Lower vegetation such as brush, shrubs, and ground covers are often time left so long as it will not interfere



with maintenance and access to the line. Both underground and overhead construction techniques generally require long-term vegetation control in the right of way. 5.6 Erosion Control in Unstable Areas Extensive erosion control measures are required for underground lines as ground disturbance extends over the entire line length with the right of way totally cleared. In areas with hilly terrain and erosive soils, significant erosion and sedimentation impacts can arise from underground construction. Due to less ground disturbing activity, overhead lines usually result in lesser erosion impacts. Careful placement of structure locations or engineered foundation arrangements can avoid or mitigate unstable geology or soils during overhead construction. Underground construction usually does not have the flexibility to avoid such areas encountered by the line route; thus, the potential for impacts to those areas increase.



APPENDIX A Aerial Map



APPENDIX B Ampacity Studies



APPENDIX C EMF Calculations



APPENDIX D Trench Details



APPENDIX E Termination and Vault Details



APPENDIX F Cost Estimates

CYMCAP 6.1 rev. 1

Study: Pawnee-Daniels Park 345 kV

Execution: Case 1 - 3500 kcmil - 1.0 mile general case

Summary Results

STL 085‐2554 (SR‐02) 131199 (10/08/13) REV 0 Appendix B

Date: 9/24/2013

Frequency: 60 Hz

Conductor Resistances: Calculated

Fraction of conductor current returningthrough sheath for single phase cables: 0

Value18

0.9

No. Name X Center Y Center Width Height

Thermal Resistivity [°C.m/W]

Installation Type: Multiple Duct Banks Backfills

Parameter UnitAmbient Soil Temperature at Installation Depth °C

Thermal Resistivity of Native Soil C.m/W

Layers Dimensions [ft]Type

1 DB 3X4 -12.521 11.995 5.042 3.99 0.5

2 DB 3X4 12.521 11.995 5.042 3.99 0.5

Standard ductbank

Standard ductbank


Load Factor Temperature Ampacity

X[ft] Y[ft] [p.u.] [°C] [A]

Summary Results

Solution converged

Cable\Cable type no Circuit Phase

Location

1 \ 1


1 A -14.474 10.817 0.75 82.4 1190

1 B -13.172 10.817 0.75 85.4 1190

1 C -11.87 10.817 0.75 83 1190

1 A -13.172 12.119 0.75 89.9 1190

1 B -11.87 12.119 0.75 87.2 1190

1 C -14.474 12.119 0.75 86.6 1190

1 A -11 87 13 422 0 75 85 9 1190

6 \ 1

1 \ 1

2 \ 1

3 \ 1

4 \ 1

5 \ 1

7 \ 1 1 A -11.87 13.422 0.75 85.9 1190

1 B -14.474 13.422 0.75 85.2 1190

1 C -13.172 13.422 0.75 88.3 1190

2 A 10.568 10.817 0.75 83.2 1190

2 B 11.87 10.817 0.75 85.4 1190

2 C 13.172 10.817 0.75 82.1 1190

2 A 13.172 13.422 0.75 85 1190

7 \ 1

8 \ 1

9 \ 1

10 \ 1

11 \ 1

12 \ 1

13 \ 1

2 B 13.172 12.119 0.75 86.3 1190

2 C 10.568 12.119 0.75 87.5 1190

2 A 11.87 12.119 0.75 89.9 1190

2 B 10.568 13.422 0.75 86.1 1190

2 C 11.87 13.422 0.75 88.3 119018 \ 1

14 \ 1

15 \ 1

16 \ 1

17 \ 1


CYMCAP 6.1 rev. 1


Execution: Case 2 - 3500 kcmil - 1.4 mile HDD case

Summary Results


Date: 9/19/2013

Frequency: 60 Hz

Conductor Resistances: Calculated

Fraction of conductor current returningthrough sheath for single phase cables: 0

Value11

0.9

No. Name X Center Y Center Width Height

Thermal Resistivity [°C.m/W]

Installation Type: Multiple Duct Banks Backfills

Parameter UnitAmbient Soil Temperature at Installation Depth °C

Thermal Resistivity of Native Soil C.m/W

Layers Dimensions [ft]Type

1 DB 3X4 -11.896 21.412 3.792 2.823 0.7

2 DB 3X4 11.896 21.412 3.792 2.823 0.7

Standard ductbank

Standard ductbank


Load Factor Temperature Ampacity

X[ft] Y[ft] [p.u.] [°C] [A]

Summary Results

Solution converged

Cable\Cable type no Circuit Phase

Location

1 \ 1


1 A -13.349 20.567 0.75 83.9 977

1 B -11.412 20.567 0.75 84.7 977

1 C -12.38 20.567 0.75 86.7 977

1 A -12.38 21.536 0.75 90 977

1 B -13.349 21.536 0.75 86.9 977

1 C -11.412 21.536 0.75 87.7 977

1 A -11 412 22 505 0 75 85 9 977

6 \ 1

1 \ 1

2 \ 1

3 \ 1

4 \ 1

5 \ 1

7 \ 1 1 A -11.412 22.505 0.75 85.9 977

1 B -12.38 22.505 0.75 87.9 977

1 C -13.349 22.505 0.75 85 977

2 A 10.443 20.567 0.75 84.8 977

2 B 12.38 20.567 0.75 83.7 977

2 C 11.412 20.567 0.75 86.7 977

2 A 11.412 21.536 0.75 90 977

7 \ 1

8 \ 1

9 \ 1

10 \ 1

11 \ 1

12 \ 1

13 \ 1

2 B 10.443 21.536 0.75 87.8 977

2 C 12.38 21.536 0.75 86.8 977

2 A 12.38 22.505 0.75 85 977

2 B 11.412 22.505 0.75 87.9 977

2 C 10.443 22.505 0.75 86 97718 \ 1

14 \ 1

15 \ 1

16 \ 1

17 \ 1


CYMCAP 6.1 rev. 1


Execution: Case 2 - 3500 kcmil - 1.4 mile HDD case

Date: 9/19/2013

Cables input data


No Unit 1

1 1

2 1

3 kV 345

4 inch2 2 7484

Description

General cable informationCable type no

Number of cores

Voltage

Conductor area4 inch2 2.7484

5 °C 90

6 °C 110

7 copper

8 u.cm 1.7241 Resistivity @20°C

Conductor area

Maximum Steady-State Conductor Temperature

Maximum Emergency Conductor Temperature

ConstructionConductor

Material

8 u.cm .7

9 1/K 0.00393

10 °C 234.5

11 J/K.m3 3.45

12 6 segments

13 No

14 0.39

y @

Temperature coefficient

Reciprocal of temperature coefficient of resistance (BETA)

Volumetric specific heat (SH)

Construction

Is cable dried?

ks (Skin effect coefficient)

15 0.37

16 inch 2.159

17 Yes

18 inch 0.067

19 inch 2.293Diameter

kp (Proximity effect coefficient)

Diameter

Conductor shield

Is layer present?

Thickness

Insulation

I l ?20 Yes

21 XLPE (unfilled)

22 K.m/w 3.5

23 0.001

24 2.3

25 inch 1.063

26 inch 4 419

Is layer present?

Material

Thermal resistivity

Dielectric loss factor - ( tan )

Relative permittivity ( )

Thickness

Diameter26 inch 4.419

27 Yes

28 semi-conducting

29 inch 0.063

30 inch 4.545

Thickness

Diameter

Insulation screen

Is layer present?

Material

Diameter


31 Yes

32 No

33 lead

34 u.cm 21.4

35 1/K 0.004

Sheath

Is layer present?

Is around each core? (Only for Three core cable)

Material

Resistivity @20°C

Temperature coefficient


36 °C 230

37 J/K.m3 1.45

38 Non-corrugated

39 inch 0.08

40 inch 4.705

41 Yes

Diameter

Reciprocal of temperature coefficient of resistance (BETA)

Volumetric specific heat (SH)

Corrugated construction

Thickness

Is layer present?

Jacket

41 Yes

42 polyethylene

43 K.m/w 3.5

44 inch 0.145

45 inch 4.995

46 inch 4.995

Is layer present?

Material

Thermal resistivity

Thickness

Diameter

Overall cable diameter

Diameter46 inch 4.995

No Unit 1

1 Yes

Diameter

Description/Value

SPECIFIC INSTALLATION DATABonding

Multiple cables per phase, single point bonded

2 0.3

3 Yes

4 6

5 YesSingle conductor cables NOT touching

Loss factor constant

Loss factor constant

Duct construction

PVC duct in concrete or buried

Resistivity (RH)

Cables touching

p p p g p

5 YesSingle conductor cables NOT touching


No Symbol Description Unit 1 2 3 4 5

1 Cable type no 1 1 1 1 1

2 Circuit no 1 1 1 1 1

3 Phase A B C A B

Temperature calculations


3 Phase A B C A B

4 c Conductor temperature °C 83.9 84.7 86.7 90 86.9

5 i Sheath/Shield temperature °C 77.8 78.6 80.6 83.9 80.8

6 j Armour/Pipe or Jacket temperature °C 77.2 78 80 83.3 80.2

7 s Exterior duct temperature °C 71.6 72.4 74.4 77.7 74.5

8 a Ambient temperature °C 11 11 11 11 11

No Symbol Description Unit 6 7 8 9 10Temperature calculations



3 Phase C A B C A

4 c Conductor temperature °C 87.7 85.9 87.9 85 84.8


6 j Armour/Pipe or Jacket temperature °C 81 79.3 81.2 78.4 78.1


p


No Symbol Description Unit 11 12 13 14 15



3 Phase B C A B C

4 c Conductor temperature °C 83.7 86.7 90 87.8 86.8

5 Sh th/Shi ld t t °C 77 7 80 5 83 8 81 7 80 6



6 j Armour/Pipe or Jacket temperature °C 77.1 80 83.3 81.1 80.1



No Symbol Description Unit 16 17 18

1 Cable type no 1 1 1

2 Circuit no 2 2 2


2 Circuit no 2 2 2

3 Phase A B C

4 c Conductor temperature °C 85 87.9 86

5 i Sheath/Shield temperature °C 78.9 81.7 79.9

6 j Armour/Pipe or Jacket temperature °C 78.3 81.2 79.3

7 s Exterior duct temperature °C 72.7 75.5 73.7

8 a Ambient temperature °C 11 11 11


Cable type no: 1

Cable type: OTHER

Cable ID: 345C3.50X

Cable title: 345 kV 3500 kcmil CU XLPE Xcel Energy



Client: Xcel Energy Prepared By: Travis HettwerProject Name: Pawnee-Daniels Park 345-kV Date: 9/26/2013Project Number: 131199 Checked By: Ryan Parker

Date: 9/27/2013Input Data

Graph Title:Number of Circuits:Calculation Height Above Ground: 3.28 ftDuctbank Depth: 3 ftDuctbank Separation: 20 ftBonding Method:Current Magnitude & Angle:

Circuit Current Phasor Circuit Current Phasor1A 242 0 2A 242 01B 242 -120 2B 242 -1201C 242 120 2C 242 120

~725 A/ckt ~725 A/ckt

Calculation Results (Based on 50 ft R/W)Distance

from Center of

ROW (feet)

Magnetic Field

Strength (mG)

Distance from

Center of ROW (feet)

Magnetic Field

Strength (mG)

Distance from


Magnetic Field

Strength (mG)

Distance from


Magnetic Field

Strength (mG)

‐50.0 0.3645 -25.0 5.4715 0.0 9.3130 25.0 4.3920-49.0 0.3920 -24.0 6.4547 1.0 9.6697 26.0 3.7741-48.0 0.4223 -23.0 7.6479 2.0 10.3322 27.0 3.2602-47.0 0.4559 -22.0 9.0905 3.0 11.3191 28.0 2.8312

Single Point

1 Transmission, 3 Cables per PhaseDouble Circuit, 725 A/ckt

-46.0 0.4932 -21.0 10.8202 4.0 12.6511 29.0 2.4713-45.0 0.5347 -20.0 12.8623 5.0 14.3409 30.0 2.1680-44.0 0.5811 -19.0 15.2124 6.0 16.3756 31.0 1.9110-43.0 0.6330 -18.0 17.8104 7.0 18.6916 32.0 1.6922-42.0 0.6913 -17.0 20.5119 8.0 21.1448 33.0 1.5050-41.0 0.7571 -16.0 23.0730 9.0 23.4933 34.0 1.3440-40.0 0.8314 -15.0 25.1712 10.0 25.4145 35.0 1.2049-39.0 0.9159 -14.0 26.4812 11.0 26.5769 36.0 1.0843-38.0 1.0122 ‐13.0 26.7836 12.0 26.7466 37.0 0.9791-37.0 1.1225 -12.0 26.0498 13.0 25.8770 38.0 0.8871-36.0 1.2492 -11.0 24.4510 14.0 24.1222 39.0 0.8062-35.0 1.3956 -10.0 22.2871 15.0 21.7716 40.0 0.7349-34.0 1.5655 -9.0 19.8842 16.0 19.1477 41.0 0.6717-33.0 1.7635 -8.0 17.5131 17.0 16.5213 42.0 0.6157-32.0 1.9955 -7.0 15.3547 18.0 14.0738 43.0 0.5657-31.0 2.2689 -6.0 13.5049 19.0 11.8995 44.0 0.5210-30.0 2.5925 -5.0 11.9988 20.0 10.0276 45.0 0.4809-29.0 2.9777 -4.0 10.8362 21.0 8.4480 46.0 0.4449-28.0 3.4385 -3.0 10.0019 22.0 7.1310 47.0 0.4124-27.0 3.9925 -2.0 9.4777 23.0 6.0398 48.0 0.3830-26.0 4.6613 -1.0 9.2500 24.0 5.1378 49.0 0.3564

50.0 0.3322

STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 EMF Calculation (725 A) Appendix C

15

20

25

30

etic

Fie

ld S

tren

gth

(mG

)Pawnee-Daniels Park 345-kV

Double Circuit, 725 A/ckt

STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 EMF Calculation (725 A)

APPENDIX C

0

5

10

-60 -40 -20 0 20 40 60

Mag

ne

Distance from Center of Ductbanks (feet)





~1450 A/ckt ~1450 A/ckt


from Center of

ROW (feet)

Magnetic Field

Strength (mG)

Distance from Center

of ROW (feet)

Magnetic Field

Strength (mG)

Distance from


Magnetic Field

Strength (mG)

Distance from


Magnetic Field

Strength (mG)

‐50.0 0.7291 -25.0 10.9429 0.0 18.6260 25.0 8.7841-49.0 0.7840 -24.0 12.9095 1.0 19.3395 26.0 7.5481-48.0 0.8447 -23.0 15.2957 2.0 20.6644 27.0 6.5204-47.0 0.9119 -22.0 18.1809 3.0 22.6382 28.0 5.6624

Single Point


47.0 0.9119 22.0 18.1809 3.0 22.6382 28.0 5.6624-46.0 0.9865 -21.0 21.6403 4.0 25.3023 29.0 4.9427-45.0 1.0695 -20.0 25.7247 5.0 28.6818 30.0 4.3360-44.0 1.1622 -19.0 30.4249 6.0 32.7513 31.0 3.8220-43.0 1.2660 -18.0 35.6208 7.0 37.3832 32.0 3.3844-42.0 1.3826 -17.0 41.0239 8.0 42.2896 33.0 3.0099-41.0 1.5141 -16.0 46.1460 9.0 46.9865 34.0 2.6880-40.0 1.6629 -15.0 50.3425 10.0 50.8291 35.0 2.4099-39.0 1.8318 -14.0 52.9625 11.0 53.1537 36.0 2.1685-38.0 2.0244 ‐13.0 53.5671 12.0 53.4932 37.0 1.9582-37.0 2.2449 -12.0 52.0996 13.0 51.7540 38.0 1.7741-36.0 2.4984 -11.0 48.9020 14.0 48.2444 39.0 1.6124-35.0 2.7912 -10.0 44.5742 15.0 43.5433 40.0 1.4697-34.0 3.1309 -9.0 39.7684 16.0 38.2953 41.0 1.3435-33.0 3.5270 -8.0 35.0263 17.0 33.0425 42.0 1.2313-32.0 3.9911 -7.0 30.7094 18.0 28.1477 43.0 1.1314-31.0 4.5377 -6.0 27.0098 19.0 23.7990 44.0 1.0420-30.0 5.1850 -5.0 23.9976 20.0 20.0552 45.0 0.9619-29.0 5.9554 -4.0 21.6725 21.0 16.8961 46.0 0.8898-28.0 6.8771 -3.0 20.0038 22.0 14.2620 47.0 0.8248-27.0 7.9850 -2.0 18.9554 23.0 12.0796 48.0 0.7661-26.0 9.3226 -1.0 18.5000 24.0 10.2757 49.0 0.7129

50.0 0.6645

STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 EMF Calculation (1450 A) APPENDIX C

30

40

50

60

etic

Fie

ld S

tren

gth

(mG



STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 EMF Calculation (1450 A)

APPENDIX C

0

10

20

-60 -40 -20 0 20 40 60

Mag

ne






~2900 A/ckt ~2900 A/ckt


from Center of

Ductbanks(feet)

Magnetic Field

Strength (mG)

Distance from

Center of Ductbanks(

feet)

Magnetic Field

Strength (mG)

Distance from

Center of Ductbanks

(feet)

Magnetic Field

Strength (mG)

Distance from

Center of Ductbanks(

feet)

Magnetic Field

Strength (mG)

‐50.0 1.4567 -25.0 21.8632 0.0 37.2134 25.0 17.5500-49.0 1.5664 -24.0 25.7923 1.0 38.6389 26.0 15.0806-48.0 1.6877 -23.0 30.5598 2.0 41.2860 27.0 13.0274-47.0 1.8219 -22.0 36.3243 3.0 45.2296 28.0 11.3131

Single Point


-46.0 1.9709 -21.0 43.2360 4.0 50.5522 29.0 9.8752-45.0 2.1367 -20.0 51.3962 5.0 57.3044 30.0 8.6630-44.0 2.3219 -19.0 60.7869 6.0 65.4349 31.0 7.6361-43.0 2.5293 -18.0 71.1680 7.0 74.6891 32.0 6.7618-42.0 2.7624 -17.0 81.9630 8.0 84.4919 33.0 6.0137-41.0 3.0251 -16.0 92.1967 9.0 93.8760 34.0 5.3704-40.0 3.3223 -15.0 100.5810 10.0 101.5532 35.0 4.8147-39.0 3.6599 -14.0 105.8156 11.0 106.1976 36.0 4.3325-38.0 4.0447 ‐13.0 107.0236 12.0 106.8760 37.0 3.9123-37.0 4.4852 -12.0 104.0916 13.0 103.4010 38.0 3.5446-36.0 4.9917 -11.0 97.7030 14.0 96.3890 39.0 3.2214-35.0 5.5767 -10.0 89.0563 15.0 86.9966 40.0 2.9364-34.0 6.2553 -9.0 79.4547 16.0 76.5115 41.0 2.6842-33.0 7.0466 -8.0 69.9802 17.0 66.0168 42.0 2.4601-32.0 7.9739 -7.0 61.3554 18.0 56.2372 43.0 2.2604-31.0 9.0661 -6.0 53.9638 19.0 47.5488 44.0 2.0818-30.0 10.3593 -5.0 47.9456 20.0 40.0690 45.0 1.9217-29.0 11.8985 -4.0 43.3002 21.0 33.7572 46.0 1.7778-28.0 13.7399 -3.0 39.9663 22.0 28.4946 47.0 1.6480-27.0 15.9535 -2.0 37.8716 23.0 24.1342 48.0 1.5306-26.0 18.6259 -1.0 36.9618 24.0 20.5301 49.0 1.4242

50.0 1.3276


60

80

100

120

etic

Fie

ld S

tren

gth

(mG




0

20

40

-60 -40 -20 0 20 40 60

Mag

ne


Draft

Xcel EnergyPawnee to Daniels Park 345 kV - 1 mile - Typical Underground in Developed Residential

Prepared by: CJS3500 kcmil Cu 2 Number of Circuits Checked by: RAP

18 Cables - 3 Cables/Phase 2 Number of Duct Banks2900 Amps 4 Number of Comm Ducts5280 feet 1 mile 24 Number of Circuits

Quantity Material Price Total Material PriceLabor &

EquipmentPriceTotal Labor

Price Total Price

96,600 $105.00 $10,143,000 $20.00 $1,932,000 $12,075,0000 $56,000.00 $0 $18,000.00 $0 $0

36 $31,000.00 $1,116,000 $15,000.00 $540,000 $1,656,00012 $8,275.00 $99,300 $3,500.00 $42,000 $141,300

0 $4,138.00 $0 $1,000.00 $0 $0220 $135.00 $29,700 $100.00 $22,000 $51,700

32,000 $8.95 $286,400 $5.00 $160,000 $446,40054 $0.00 $0 $1,500.00 $81,000 $81,000

Communication System:21,800 $2.50 $54,500 $4.00 $87,200 $141,700

2 $10,000.00 $20,000 $5,000.00 $10,000 $30,0008 $4,000.00 $32,000 $4,000.00 $32,000 $64,000

Temperature Monitoring System:10,900 $3.50 $38,150 $4.00 $43,600 $81,750

1 $4,000.00 $4,000 $3,000.00 $3,000 $7,0001 $4,000.00 $4,000 $3,000.00 $3,000 $7,000

Duct Bank and Earthwork:128,000 $9.00 $1,152,000 $8.00 $1,024,000 $2,176,000

32,000 $3.00 $96,000 $6.00 $192,000 $288,00021,400 $3.00 $64,200 $6.00 $128,400 $192,60010,700 $3.00 $32,100 $6.00 $64,200 $96,30012,800 $15.00 $192,000 $5.00 $64,000 $256,00015,430 $15.00 $231,450 $45.00 $694,350 $925,800

9,430 $25.00 $235,750 $25.00 $235,750 $471,5006,000 $125.00 $750,000 $25.00 $150,000 $900,000

12 $35,000.00 $420,000 $25,000.00 $300,000 $720,0010 $750.00 $0 $550.00 $0 $00 $275.00 $0 $50.00 $0 $00 $200.00 $0 $150.00 $0 $0

220 $25.00 $5,500 $25.00 $5,500 $11,00010,560 $25.00 $264,000 $30.00 $316,800 $580,800

1,500 $20.00 $30,000 $10.00 $15,000 $45,00050 $25.00 $1,250 $5.00 $250 $1,500

340 $25.00 $8,500 $15.00 $5,100 $13,6000 $2.50 $0 $2.50 $0 $0

517,450 $0.25 $129,363 $0.25 $129,363 $258,7254 $100.00 $400 $750.00 $3,000 $3,4000 $0.00 $0 $0 $00 $0.00 $0 $0 $0

$15,439,563 $6,283,513 $21,723,076Unallocated Costs:

15% 2,315,934 $980,228 $3,296,1621% $0 $62,835 $62,8353% $0 $188,505 $188,5050% $0 $0 $0

$3,626,159 $1,389,581 $5,015,740$21,381,656 $8,904,662 $30,286,319

$ $21,381,656 $ $8,904,662 $30,286,319

Cable clamps, eachContinuity conductor, per foot

Description

Cable and Accessories Section:

Grounding system for structures, eachGrounding system for vaults, each

XLPE cable, per footTerminators, eachSplices, each

Jacket integrity test, cable segment

Fiber-optic cable, per footFiber-optic cable splices (incl. Enclosures), each

Fiber-optic cable splices, eachFiber-optic cable, per foot

Communication conduit, per foot

Handholes, each

Cable conduit, per foot

Terminal equipment, each

Continuity conduit, per foot

TM conduit, per foot

Jack and bore, per foot

Excavation, no rock, including hauling, per cubic yardSoil backfill, including hauling, per cubic yard

Conduit spacers, each

Duct encasement concrete, per cubic yardManholes, each

Total Price (should add up to Lump Sum Price)

Subtotal

SubtotalHard Dollar Overheads: Escalation,AFUDC,etc.., lot

Internal Engineering, lot

Construction Management

Mobilization, eachDemobilization, each

Contract Engineering

Contingency

Landscape restoration, per square foot

Traffic control, daysLoam and seed, per square foot

Sheeting and shoring, per footPavement repair, per square footCurb repair, per square foot

1" steel plating, per footBore grouting, per cubic yardBore spacer, each

Sidewalk repair, per square foot

STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 Appendix F

Draft

Xcel EnergyPawnee to Daniels Park 345 kV - 1.4 mile - Sulphur to IREA Parker

Prepared by: CJS3500 kcmil Cu 2 Number of Circuits Checked by: RAP

18 Cables - 3 Cables/Phase 2 Number of Duct Banks2900 Amps 4 Number of Comm Ducts7392 feet 1.4 miles 24 Number of Circuits

Quantity Material Price Total Material PriceLabor &

EquipmentPriceTotal Labor

Price Total Price

136,700 $105.00 $14,353,500 $20.00 $2,734,000 $17,087,50036 $56,000.00 $2,016,000 $18,000.00 $648,000 $2,664,00072 $31,000.00 $2,232,000 $15,000.00 $1,080,000 $3,312,00012 $8,275.00 $99,300 $3,500.00 $42,000 $141,30012 $4,138.00 $49,656 $1,000.00 $12,000 $61,656

550 $135.00 $74,250 $100.00 $55,000 $129,25046,100 $8.95 $412,595 $5.00 $230,500 $643,095

90 $0.00 $0 $1,500.00 $135,000 $135,000

Communication System:31,500 $2.50 $78,750 $4.00 $126,000 $204,750

0 $10,000.00 $0 $5,000.00 $0 $016 $4,000.00 $64,000 $4,000.00 $64,000 $128,000

Temperature Monitoring System:15,800 $3.50 $55,300 $4.00 $63,200 $118,500

0 $4,000.00 $0 $3,000.00 $0 $02 $4,000.00 $8,000 $3,000.00 $6,000 $14,000

Duct Bank and Earthwork:179,200 $9.00 $1,612,800 $8.00 $1,433,600 $3,046,400

44,800 $3.00 $134,400 $6.00 $268,800 $403,20029,900 $3.00 $89,700 $6.00 $179,400 $269,10015,000 $3.00 $45,000 $6.00 $90,000 $135,000

Cable clamps, eachContinuity conductor, per foot

Description

Cable and Accessories Section:

Grounding system for structures, eachGrounding system for vaults, each

XLPE cable, per footTerminators, eachSplices, each

Jacket integrity test, cable segment

Fiber-optic cable, per footFiber-optic cable splices (incl. Enclosures), each

Fiber-optic cable splices, eachFiber-optic cable, per foot

Communication conduit, per foot

Handholes, each

Cable conduit, per foot

Terminal equipment, each

Continuity conduit, per foot

TM conduit, per foot 15,000 $3.00 $45,000 $6.00 $90,000 $135,00017,440 $15.00 $261,600 $5.00 $87,200 $348,80022,130 $15.00 $331,950 $45.00 $995,850 $1,327,80014,030 $25.00 $350,750 $25.00 $350,750 $701,500

8,100 $125.00 $1,012,500 $25.00 $202,500 $1,215,00024 $35,000.00 $840,001 $25,000.00 $600,001 $1,440,001

400 $750.00 $300,000 $550.00 $220,000 $520,00080 $275.00 $22,000 $50.00 $4,000 $26,00059 $200.00 $11,800 $150.00 $8,850 $20,650

1,870 $25.00 $46,750 $25.00 $46,750 $93,50014,390 $25.00 $359,750 $30.00 $431,700 $791,45017,290 $20.00 $345,800 $10.00 $172,900 $518,700

140 $25.00 $3,500 $5.00 $700 $4,200340 $25.00 $8,500 $15.00 $5,100 $13,600

7,200 $2.50 $18,000 $2.50 $18,000 $36,000525,050 $0.25 $131,263 $0.25 $131,263 $262,525

21 $100.00 $2,100 $750.00 $15,750 $17,8501 $0 $105,000.00 $105,000 $105,0001 $0 $105,000.00 $105,000 $105,000

$25,371,514 $10,668,813 $36,040,327Unallocated Costs:

15% $3,805,728 $1,696,342 $5,502,0701% $0 $106,688 $106,6883% $0 $320,064 $320,0642% $0 $213,376 $213,376

$2,251,505 $6,071,285 $8,322,790$31,428,747 $19,076,569 $50,505,316

$ $31,428,747 $ $19,076,569 $50,505,316

TM conduit, per foot

Jack and bore, per foot

Excavation, no rock, including hauling, per cubic yardSoil backfill, including hauling, per cubic yard

Conduit spacers, each

Duct encasement concrete, per cubic yardManholes, each

Total Price (should add up to Lump Sum Price)

Subtotal

Subtotal

Contract EngineeringInternal Engineering

Construction Management

Mobilization, eachDemobilization, each

Hard Dollar Overheads: Escalation,AFUDC,…etc, lot

Contingency

Landscape restoration, per square foot

Traffic control, daysLoam and seed, per square foot

Sheeting and shoring, per footPavement repair, per square footCurb repair, per square foot

1" steel plating, per footBore grouting, per cubic yardBore spacer, each

Sidewalk repair, per square foot

STL 085-2554 (SR-02) 131199 (10/08/13) REV 0 Appendix F

R

PREL

IMIN

AR

Y

R

PREL

IMIN

AR

Y

085-2544 Xcel Pawnee-Daniels Park Underground Report Rev2 02-14-14085-2544 Xcel Pawnee-Daniels Park AppendicesEMF Case 2 Calculation (725 A)EMF Case 2 Calculation (725 A) chartEMF Case 3 Calculation (1450 A)EMF Case 3 Calculation (1450 A) chartEMF Case 4 Calculation (2900 A)EMF Case 4 Calculation (2900 A) chartAppendices B.pdfCase 1 - 3500 kcmil - 1.0 mile general routeCase 2 - 3500 kcmil - 1.4 mile specified routeCase 2 - 3500 kcmil - 1.4 mile specified route - cables

Binder1.pdfU3-1U3-2U3-3U3-4U3-5

345kV UG-Overhead transition site General Arrangment345kV UG-Overhead transition site One Line345kV UG-Overhead transition site Section View

underground feasibility study - xcel energy...underground cable system. a critical factor of the...

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