A subsidiary of Pinnacle West Capital Corporation CUSTOMER/ TWIN ARROWS PROJECT V1 Facility Study Report APS Contract 52149 Prepared by: Arizona Public Service Company Transmission & Distribution Asset Management And Transmission Planning
Contents...Page Executive Summary...3 Introduction...5 Study Objectives...5 Project and Interconnection Information...5 Facility Interconnection Plan...5 Study Assumptions and Methodology...7 Facility Study Results...7 Interconnection Plan and Delivery to the Coconino 69 kv System...7 Short Circuit Analysis...8 Interconnection Cost Estimates...8 Appendix A...One-Line Diagram & Location Map Appendix B...Power Flow Result Summary Appendix C...Power Flow Diagrams Appendix D...Interconnection Cost Estimates - 2 -
Executive Summary CUSTOMER (CUSTOMER) is evaluating an additional Point of Delivery to the Arizona Public Service (APS) transmission system. The proposed Project is known as the Twin Arrows Project, and would be served off APS s Coconino Winslow 69 kv transmission line. CUSTOMER projected that this Point of Delivery would add 800 kw onto the APS transmission system in 2009, and ultimately increase to 2.8 MW of load by 2018. The planned commercial operation date of the Twin Arrows Project is December 2009. The Project location is approximately 25 miles east of Flagstaff, AZ and approximately 2 miles east of APS s Padre. Appendix A shows a map of the Flagstaff area and the proposed facility location. At the Customer s request, APS determined the possible transmission paths from the Point of Delivery plus associated transmission reinforcements required to interconnect the Twin Arrows Project. This Facility Study (Twin Arrows Project, APS Contract 52149) evaluated the following configuration for interconnecting the Project. The Point of Interconnection for the proposed Twin Arrows Project to the APS Coconino 69 kv system is a tap into the Coconino Winslow 69 kv line. CUSTOMER proposes to take delivery at the Coconino Winslow 69 kv line and build its own distribution substation. A new ¾ mile 69 kv line needs to be built off the existing Coconino Winslow 69 kv line to serve the proposed new CUSTOMER (Twin Arrows) substation. APS also proposes to install, at the new substation, a new 69 kv breaker and a 69 kv primary meter. Appendix A shows a one-line drawing indicating the new facilities. APS performed the Facility Study modeling the heavy summer coincident peak loads demand power flow base cases in the 2009 timeframe. Power flow analysis was performed and the results were used for the evaluation of the interconnection plan. Short circuit studies were performed to evaluate the system impact of adding the Project to the APS transmission system. Interconnection costs and timelines were estimated for the interconnection plan based on the approximate location. The study results concluded that the serviceability of the ultimate Project load of 2.8 MW can be achieved without adversely impacting the APS transmission system. Also, the short circuit study results indicate that adequate protection is maintained and the proposed interconnection Project does not have a negative impact on the system. The total cost to install the proposed Project is $2,007k and the Project lead time to build the proposed facilities is 22 26 months. The long lead time is due to the fact that a State land permit is required to build the new 69 kv line tap. In addition, CUSTOMER needs to provide a substation site for the proposed Project. These projected lead times make a 2009 in-service unachievable. A realistic in-service date would be no sooner than - 3 -
the end of 2010. The Interconnection costs and timeline estimates are listed in Table 1 below. Table 1: Summary of Project Interconnection Costs Interconnection Plan Cost Estimate Lead Time (x 1000) Responsible Agency Equipment $1,510 6 months APS Line Construction $480 2.5 months State Line Right of Way $17 18-24 months APS Grand Total $2,007 22-26 months - 4 -
Introduction CUSTOMER (CUSTOMER) has submitted a completed Facilities Study Agreement to Arizona Public Service (APS) for the Twin Arrows Project under the APS OATT. The proposed Project consists of an additional Point of Delivery to service new load. The initial load will be 800 kw in 2009, and will gradually increase to 2.8 MW by 2018. CUSTOMER projected that the planned commercial operation date of the Project would be December 2009. The proposed Project will be located approximately 25 miles east of Flagstaff, Arizona, and approximately 2 miles east of the existing Padre substation. See Appendix A for a map showing the approximate locations. APS requires that an interconnection Facility Study be conducted to identify any Direct Assignment Facilities and/or Network Upgrades as a result of interconnecting the proposed Project to the APS transmission system. This report summarizes the results of the Facility Study. Study Objectives There are three main objectives of this Study. One objective is to identify the interconnection point and determine any associated transmission reinforcements required to interconnect the Twin Arrows Project. The second objective is to evaluate if there is transmission capacity available to service the load of the Project on APS s system and, if not, identify what system additions would be needed to service the load of the Project. The third objective is to identify estimated lead times and evaluate if the requested inservice date is achievable. CUSTOMER will be responsible for all system additions required to service the Project load. The Study provides cost and timeline estimates for the interconnection plan and system additions required for the proposed Project. Project and Interconnection Information The general Project and interconnection information is provided below: Project Location: Southeast Coconino District, 25 miles east of Flagstaff, Arizona Initial Load: 800 kw (was projected to start in 2009 will be delayed) Maximum Load: 2.8 MW Power Factor: CUSTOMER must maintain a load power factor of 0.95 lagging or higher at the point of delivery. Facility Interconnection Plan The interconnection plan evaluated as part of the Facility Study is listed below: - 5 -
The Point of Interconnection for the proposed Twin Arrows Project to the APS Coconino 69 kv system is a tap into the Coconino Winslow 69 kv line. CUSTOMER proposes to take delivery at the Coconino Winslow 69 kv line and build its own distribution substation. A new ¾ mile 69 kv line needs to be built off the existing Coconino Winslow 69 kv line to serve the proposed new CUSTOMER (Twin Arrows) substation. CUSTOMER will provide the electrical infrastructure and lines needed for their system up to and including the transformer that would connect their load to the APS 69 kv system. CUSTOMER will pay for and APS will install the 69 kv tap, a 69 kv breaker, relays, supervisory controls to the breaker, primary metering and communications equipment. APS will own and operate all 69 kv equipment and controls. The point at which change of ownership takes place will be at the primary metering point (see below). The one-line drawing is also shown in Appendix A. CUSTOMER (Twin Arrows) Point of Interconnection (POI) 69kV bus 69kV line 69kV breaker PM Primary Metering Point Approximate circuit length (miles) Coconino Padre 21.0 Padre POI 2.0 POI Sunshine 13.4 Sunshine Leupp Jct 13.7 Leupp Jct Winslow 10.5 Twin Arrows Leupp Jct. PM Coconino Winslow 108 MVA 108 MVA Padre POI Sunshine * New additions to the Coconino 69 kv System are shown in blue - 6 -
Study Assumptions and Methodology APS conducted Power Flow studies using a 2009 heavy load summer base case. This base case modeled all APS approved transmission projects that are expected to be operational by summer 2009. Proposed generation projects in APS control area that have an interconnection queue date ahead of this Project and have an online date prior to summer 2009 were modeled. The pre-project base case was tested to ensure it meets WECC/NERC and APS planning standards. The proposed load was modeled as one 2.8 MW constant power load with 0.95 power factor for this Facility Study. Power flow studies were performed to evaluate the impact of the proposed Project on the existing transmission system. Under normal operating conditions (all elements inservice); the continuous rating of any system element should not be exceeded. For single-contingency conditions, the following guidelines were followed: Sub-transmission lines should not exceed 100% of their continuous rating. 230/69 kv transformers should not exceed 120% of their top FOA rating measured at the 69 kv level. 69 kv voltage deviations should be less than 5% at unregulated substations. 69 kv voltage deviations should be less than 10% for regulated substations. Where these guidelines were not met, options were evaluated to find the best solution that would bring the system to within guidelines. Short circuit studies were performed to evaluate the impact of the Project on selected substation breaker duties and coordinated settings. Interconnection cost estimates are provided for the interconnection plan evaluated. Facility Study Results The results of the Facility study provide a plan that details any system upgrades and/or additions required to interconnect the Project to the Coconino 69 kv system. Interconnection Plan and Delivery to the Coconino 69 kv System Coconino Winslow 69 kv Line Tap With the Twin Arrows tap into the Coconino Winslow 69 kv line there are no limiting factors during normal (N-0) conditions or single contingency (N-1) conditions. - 7 -
Based on the Study results, there are no system upgrades and/or additions needed for this Interconnection Plan. Appendix B shows the results of the power flow studies. Appendix C illustrates the power flows in APS s Coconino 69 kv system with and without the new proposed CUSTOMER (Twin Arrows) substation. Short Circuit Analysis Short circuit studies were performed on the facility interconnection plan as part of this Study. The study included three-phase and phase-to-ground fault analysis. The study results are presented here in Table 2 below. Table 2: Summary of Short Circuit Study Evaluation Twin Arrows Fault Duty Base Case With Twin Arrows POI Min. Brkr Station 3 Ph. (ka) X/R Ph-G (ka) X/R 3 Ph. (ka) X/R Ph-G (ka) X/R Rating (ka) Twin Arrows NA NA NA NA 5.09 12.7 1.56 4.4 31 Coconino 10.01 10.1 11.68 11.2 11.07 9.3 11.25 10.3 40 Winslow 3.03 4.6 1.68 4.2 3.69 4.2 1.69 4.2 31 * Pre-Fault Voltage = 1.05 pu (@ 69kV base voltage) As can be seen from Table 2, the interconnection of the Project does not cause the existing substation breakers to exceed their minimum rating. Interconnection Cost Estimates The interconnection cost is based solely on the plan of service as provided under sections Facility Interconnection Plan and Facility Study Results. 69 kv Line & Construction Assumptions: No 12 kv underbuild is included in the estimate. Land survey was not conducted for estimating line route. Right of Way (ROW) required is 40 feet wide. Access and Lay Down Yards are not included in the estimate. Land cost is not included in the estimate. CUSTOMER will provide a substation site for the proposed Project. A State land permit is required for the 69 kv line tap. State or Indian land acquisition (lead) time is typically 18 to 24 months. CUSTOMER will provide site grading. - 8 -
CUSTOMER is obtaining ROW for the road accessing the substation, and will perform all work on the road. CUSTOMER will provide access to APS 69kV yard. All Estimates are in 2009 dollars. The total cost to install the proposed Project is $2,007k and the Project lead time to build the proposed facilities is 18 24 months. The State land permit process is the critical factor for the long lead time of 22 26 months, which is needed to build the new 69 kv line tap. These lead times make it impossible for an in-service date of late 2009. A detailed cost breakdown of the proposed Project is shown in Appendix D. - 9 -
Appendix A (One-Line Diagram & Location Map)
Twin Arrows Facility Study APS Contract 52149 CUSTOMER (Twin Arrows) Point of Interconnection (POI) 69kV bus 69kV line 69kV breaker PM Approximate circuit length (miles) Coconino Padre Padre POI POI Sunshine Sunshine Leupp Jct Leupp Jct Winslow 21.0 2.0 13.4 13.7 10.5 Leupp Jct. Twin Arrows PM Coconino Winslow 108 MVA Padre 108 MVA POI * New additions to the Coconino 69 kv System are shown in blue Sunshine Primary Metering Point
Appendix B (Power Flow Result Summary)
Twin Arrows Coconino 69 kv System Outage Summary 2009 Outage Description From Bus Name Overload Element Base KV To Bus Name Base KV Rating Base case Flow MVA MW MVAR Amps Loading (%) Comments No Overload or Voltage Issues
Appendix C (Power Flow Diagrams)
2009 Base Case without CUSTOMER (Twin Arrows) 69 kv 2009 Base Case with CUSTOMER (Twin Arrows) 69 kv
Appendix D (Interconnection Cost Estimates)
Equipment Cost Estimates Equipment Description Design Time Construction Time Estimated Cost (x 1000) Engineering and Design 6 months NA $128 Below Grade 6 months 3 months $413 Construction Labor (Steel, Equipment, & Control) NA 3 months $556 Steel Structures 6 months 3 months $32 Electrical Equipment 6 months 3 months $155 Control and Communications 6 months 3 months $226 Grand Total 6 months 3 months $1,510 Line Section From To POI TWNARWS New Line Length (mi) 69 kv Line Cost Estimates Conductor Type Design time (MO) Construction time (MO) Estimated Cost (x 1000) Comments 0.75 795AA 2.5 2.5 $480 single circuit Grand Total 0.75 2.5 2.5 $480 Right of Way (ROW) Cost Estimates Line Section New Line ROW Total Est. Land Value From To Length (mi) Time (mo) Estimated Cost (x 1000) Per Acre (x 1000) Land Type (mi) Private BLM State Indian Comments POI TWNARWS 0.50 18-24 $6 $1 0.50 section 1 POI TWNARWS 0.25 18-24 $11 $7 0.25 section 2 Grand Total 0.75 18-24 $17