Cluster Addendum 1. INTRODUCTION This Interconnection Customer (IC), submitted a Small Generator Interconnection Request (IR) to Arizona Public Service Company (APS) for their proposed project, located south of the Papago Freeway at 33⁰30'29.13"N 113⁰02'10.50"W in Maricopa County, Arizona (approximately 7 miles west of Tonopah, Arizona). The Interconnection Customer (IC) requested Energy Resource Interconnection Service (ERIS), and plans to install 20 MW of photovoltaic solar generation with a requested In-Service Date of October 31, 2012. The project s requested Point of Interconnection (POI) is the Harquahala Tap - Tonopah 69 kv line. The project is Queue Position 140 () in the APS FERC generation interconnection queue. On August 23, 2010, Arizona Public Service Company (APS) filed a request for a one-time waiver of the current study order of Interconnection Requests (IR) to allow a cluster study based in the Gila Bend area. This geographically targeted one-time waiver request of APS current interconnection queue procedure was changed to: 1) allow APS to study all SGIP and LGIP projects submitted in the Gila Bend area in first and second quarter of 2010 as a single cluster, 2) the clustered IRs will share the cost of common upgrades on a pro-rata basis, 3) each project subject to the cluster was given a one-time opportunity to opt out of the cluster, and 4) APS will evaluate projects outside of the cluster as if the clustering never occurred. On September 29, 2010, the Federal Energy Regulatory Commission (FERC) granted this waiver. is one of the projects in the cluster. General cluster results are captured in the general cluster SIS report. This addendum addresses project specific details and results. The Interconnection Customer has chosen to interconnect as an ERIS. Therefore, delivery of the output beyond the POI would be on an as-available basis only. The delivery of the output would be subject to the firm or non-firm transmission capacity that may be available when a transmission service request is made. Nothing in this report constitutes an offer of transmission service or confers upon the Interconnection Customer, any right to receive transmission service. APS may not have the Available Transfer Capability (ATC) to support the Transmission Service for the interconnection described in this report. It should also be noted that the results in this SIS are dependent upon the assumed topology and timing of new projects in the Gila Bend area, which are subject to change. The APS transmission and sub-transmission systems are continuously being evaluated. The planned reinforcements and their in-service dates are often revised depending upon local area load forecasts. A summary of the Interconnection costs and schedule estimates are shown below in Tables 1.1 and 1.2. Page 1 of 11
Table 1.1: Summary of Interconnection Cost and Schedule Estimates Facility 1st Position 2nd Position Costs Timeline Costs Timeline Local Network Upgrades (LNUs) $1,725,000 12 Months $135,000 10 Months Transmission Provider's Interconnection Facilities $141,000 12 Months $141,000 8 Months Total $1,866,000 12 Months $276,000 10 Months Table 1.2: Pro-Rata Share of System Network Upgrade Costs and Schedule Estimate Facility Costs Timeline Pro-Rata Share of System Network Upgrades (SNUs) $7,656,561 43-49 Months Total $7,656,561 43-49 Months There are two different costs shown in Table 1.1 above. Since is sharing the POI with Q154, the cost to interconnect will depend on the order the projects move forward and are constructed. The first project to interconnect will correspond to the 1 st position, and the second project to interconnect will correspond to the 2 nd position. The interconnection costs shown in Table 1.1 above are specifically to interconnect into the APS transmission system. The System Network Upgrades (SNUs), as described in the main report, are shown in Table 1.2 above. The total cost to interconnect into the APS system is $9,522,561 for the 1 st position, and $7,932,561 for the 2 nd position. The total estimated completion time for interconnecting the project is 43 49 Months no matter what position it is interconnected, due to the construction of the SNUs. The actual start of construction would occur when the IC provides written authorization to proceed, provided all interconnection studies are complete, and agreements and funding arrangements are in place. Therefore, the requested In-Service Date of October 31, 2012 cannot be met. will be given the first available In-Service Date once the Interconnection Agreement has been signed, which will be based on the Network Upgrades required at that time. Figure 1.2 below shows a general depiction of the 69 kv system around s proposed POI. The other Cluster projects are not shown, however higher queued projects are shown, as well as any non-ferc 12 kv projects. Page 2 of 11
Figure 1.2: Project Location and 69 kv System Harquahala 20 POI#6 Tonopah BK4 To Buckeye Wintersburg Saddle Mountain 15 #4 To Wintersburg Tap Horn 13.5 Q84 #1 Aztec 17 Q85 20 Hyder 9.4 Q64 County Line To Gila Bend Note: The numbers within the circles represent MW values. # 69kV bus 69kV line 69kV breaker New 69 kv ring bus Cluster generator Non-cluster generator Non-FERC 12 kv projects 2. RESULTS The Cluster report details the overall results. Individual project results will only be noted in the project specific appendix if something is deemed confidential from the remainder of the Cluster or if it specifically affects the project or project model. All other results are included in the main Cluster report. Thermal: The 69/34.5 kv transformer showed N-0 loading levels of 100-101% in all light load cases, and N-0 loading levels of ~100% in the 2013 heavy summer cases. Transient Stability: The project models appeared unaffected by the localized undamped response of the three N-1 contingencies mentioned in the main report. Sample Transient Plots for two contingencies are shown on the following pages. They reflect a 2013 LL case. The first plot (N-1 POIBUS6 - BUCKEYE 69 kv) represents the undamped behavior noted in the main report, prior to mitigation with a dynamic reactive device. The second plot (N-1 SADDLE MTN- HARQAHALA TAP 69 kv) shows a more typical response. Page 3 of 11
N-1 Contingency: POIBUS_6 - Buckeye 69 kv Page 4 of 11
N-1 Contingency: Saddle Mountain - Harquahala Tap 69 kv Page 5 of 11
3. PROJECT MODELING All projects were assumed to be generating at maximum output. Projects consisted of an equivalent generator, equivalent inverter transformer, station transformer, and gen-tie. Individual project collector systems were not modeled. New switching stations were modeled, bisecting existing lines, based on interconnection requirements and locations. Some projects required additional shunt devices to provide the full +/- 0.95 pf at the POI. APS allows the project's reactive support to be made up of dynamic VAr and switched static VAr devices. The reactive devices used to achieve +/- 0.95 power factor as measured at the generator terminal must be dynamic. Any additional reactive support required to compensate for losses between the generator terminals and the POI may be made up of switched static reactive devices and/or any additional reactive capability of the generator beyond 0.95 power factor. has selected the AE Solaron 500-1000V inverters (500 kw). Based on the PQ Diagram provided, the inverter is not able to provide +/- 0.95 pf at the generator terminals for all MW output levels. The dynamic reactive power requirement is based upon the +/- 0.95 power factor requirement and is calculated as follows: In order to meet the dynamic reactive power requirements for the project, elected to install additional inverters to the project, installing a total of forty-two (42) 500 kw inverters, providing 21 MVA. With the additional inverters, the project provides +/- 0.952 pf at Pmax. APS accepted this approximation of the +/- 0.95 pf requirement. (Note: The generator output is still limited to 20 MW.) The additional reactive power requirement to provide +/- 0.95 pf at the POI may be provided by static reactive support. needs to install a 3.7 MVAr shunt capacitor at the 34.5 kv bus, or equivalent. Page 6 of 11
Major components of the equivalent project model include: Gen-tie: 0.1 mile 3/0 ACSR Station Transformer: 1 x 20 MVA, 69/34.5 kv transformer Inverter Transformer: 1 x 21 MVA, 34.5/0.48 kv transformer Generator: 20 MW, equivalent of forty (40) 500 kva AE Solaron inverters, +/- 0.95 pf capability (pf provided by additional inverters) Shunt capacitor: 3.7 MVAr shunt capacitor at 34.5 kva bus to compensate for project losses and achieve +/- 0.95 pf at the POI 1. Figure 3.1: Project Model and POI Harquahala Tap 69 kv New POI BUS Tonopah 69 kv POI 69 kv 34.5 kv 0.48 kv Gen-tie 0.1 miles 3/0 ACSR 20 MVA Z= 8% on 12 MVA X/R= 30 10 x 2 MVA Z= 5.75% on 2 MVA X/R= 7.2 AND 1 x 1 MVA Z= 5.75% on 1 MVA X/R= 7.2 20 MW 1 This value was calculated to meet the minimum power factor requirements, based upon the project model provided. Page 7 of 11
4. TRANSIENT STABILITY MODELING The trip times were updated based on the Extended Ride-Through Option provided in the AE Solaron documentation. Those values are shown in the table below in red. solaron.p Rev 1 10/29/10 PSLF Modeling Rev 1B, 3/3/11 Default PSLF Modeling Rev 1B, 3/3/11 Ext Ride-Through Model 500-1000V rsrc 0 0 0 xsrc 0 0 0 Vratio 1.2 1.2 1.2 Iratio 1.1 1.1 1.1 Tdc 0.003 0.003 0.003 Kpdc 1.8 1.8 1.8 Kidc 22.5 22.5 22.5 Kpq 0.4 0.4 0.4 Kiq 25 25 25 Ilim From Table From Table 1.12 OV1L 1.2 1.2 1.2 OV1T 0.02 0.2 0.2 OV2L 1.1 1.1 1.1 OV2T 2.5 2.5 2.5 UV1L 0.5 0.5 0.5 UV1T 0.02 1.1 1.1 UV2L 0.88 0.88 0.88 UV2T 5 5 5 OFL 60.5 62.5 62.5 OFT 0.02 2 2.0 UFL 57 57 57 UFT 0.02 2 2.0 Page 8 of 11
5. COST AND CONSTRUCTION SCHEDULE ESTIMATES The cost and time estimates represent good faith estimates necessary to interconnect to the system. The non-binding, good faith cost and time estimates are tabulated below. Assumptions: Permit costs are not included in the estimate. All weather access road costs are not included in the estimate. Land acquisition/row costs are not included in the estimate as it was assumed parcel for switchyard would be deeded to APS from the IC. Access & Lay Down Yards are not included in the estimate. Rough grading costs are not included in the estimate. APS will construct, own and operate the 69 kv facilities in the new APS switchyard and the portion of line from the 69 kv bus up to the first structure outside the sub fence. The IC will construct, own and maintain the 69 kv gen-tie from the first structure outside the sub fence to the site. The IC will be responsible for providing a fiber optic communications path from the facility to the new APS switchyard. Line estimates do not include costs to reconfigure APS lines as a result of IC 69 kv route or design. All estimates are in 2012 dollars. Due to sharing an interconnection into a new APS switchyard with another project (Q154), the interconnection costs shown below are separated depending upon the timing of the two generators interconnecting into the system. The first generator to interconnect will pay the larger amount required to build the new switchyard. The second generator to interconnect will only pay for the upgrades required to bring an additional 69 kv line into the switchyard. Tables 5.1 and 5.2 below provide a summary of the Local Network Upgrades (LNUs) and Transmission Provider s Interconnection Facilities (TPIF) cost estimates for both interconnection scenarios. Table 5.3 below shows the pro-rata share of the SNU costs required for this cluster, as well as the estimated construction schedule to complete the upgrades. Table 5.1: Project Cost Summary (1 st Position) Equipment Description Local Network Upgrades (LNUs) Transmission Provider's Interconnection Facilities New APS 69 kv Switchyard $1,475,000 $141,000 Overhead Line Work $105,000 $0 Communications (Leased T1 Line) $145,000 $0 Subtotal $1,725,000 $141,000 Grand Total $1,866,000 Page 9 of 11
. Table 5.2: Project Cost Summary (2 nd Position) Equipment Description Local Network Upgrades (LNUs) Transmission Provider's Interconnection Facilities New 69 kv Line Terminal $91,000 $141,000 Communications (Leased T1 Line) $44,000 $0 Subtotal $135,000 $141,000 Grand Total $276,000 Table 5.3: Pro-Rata Share of System Network Upgrade Costs and Schedule Estimate Facility Costs Timeline Pro-Rata Share of System Network Upgrades (SNUs) $7,656,561 43-49 Months Total $7,656,561 43-49 Months The interconnection costs shown in Tables 5.1 and 5.2 above are specifically to interconnect into the APS transmission system. The System Network Upgrades (SNUs), as described in the main report, are shown in Table 5.3 above. The total cost to interconnect into the APS system is $9,522,561 for the 1 st position, and $7,932,561 for the 2 nd position. The SNU cost responsibility for a specific individual project will be based on the pro-rata share as identified above, and may change (increase or decrease) depending on the remaining projects in the cluster as well as the timing of the specific project s advancement through the APS interconnection process. All network upgrade costs (LNUs and SNUs) are considered APS Network Upgrades, which are typically repaid to the IC, per FERC rules, as transmission credits over a maximum of twenty (20) years. The Transmission Provider s Interconnection Facilities (TPIF) include the necessary switches, bus work, etc needed to bring the generation tie-line into the new APS switchyard. These costs are the sole responsibility of the Interconnection Customer. Unlike Network Upgrades, these costs are not reimbursable. Tables 5.4 and 5.5 below provide a summary of the construction schedules for both interconnection scenarios. The construction schedule for the SNUs can be found in Table 5.3 above. Table 5.4: Construction Schedule Estimate (1 st Position) Facility Schedule New APS 69 kv Switchyard 12 Months Overhead Line Work 9 Months Communications (Leased T1 Line) 8 Months Total 12 Months. Page 10 of 11
Table 5.5: Construction Schedule Estimate (2 nd Position) Facility Schedule New 69 kv Line Terminal 10 Months Communications (Leased T1 Line) 8 Months Total 10 Months The total estimated completion time for interconnecting the project is 43 49 Months no matter what position it is interconnected, due to the construction of the SNUs. The actual start of construction would occur when the IC provides written authorization to proceed, provided all interconnection studies are complete, and agreements and funding arrangements are in place. Therefore, the requested In-Service Date of October 31, 2012 cannot be met. will be given the first available In-Service Date once the Interconnection Agreement has been signed, which will be based on the Network Upgrades required at that time. Note: This cluster SIS may need to be re-studied if all projects studied as part of this cluster do not move forward to the Facilities Study. If this occurs, the required upgrades, the total estimated costs and the pro-rata shares of the estimated costs will be adjusted and the pro-rata costs shown in Table 5.3 may change (network upgrade costs associated with each project could increase or decrease and may result in an increase in cost up to the full amount of total upgrades). Page 11 of 11