a subsidiary of pinnacle west capital corporation · 2009. 9. 16. · cost estimates ... (to mead)...

A subsidiary of Pinnacle West Capital Corporation

Interconnection Feasibility Study Report

Wind Generation Project APS Q062

By

Arizona Public Service Company Transmission Planning

September 15, 2009

Prepared by Chad Thomson, P.E.

(Utility System Efficiencies, Inc.)

Report September 15, 2009 Interconnection Feasibility Study Q062 Wind Generation Project

5899

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Table of Contents

1. Executive Summary ................................................................................................................ 3 2. Study Assumptions ................................................................................................................. 3. Power Flow Cases................................................................................................................... 4. Study Methodology.................................................................................................................

4.1. Post-Transient Governor Power Flow Analysis ............................................................. 4.2. Short Circuit Analysis...................................................................................................

5. Study Results ........................................................................................................................ 5.1. Thermal Overloads........................................................................................................

5.1.1. 2012 Light Spring without Q036 .......................................................................... 5.1.2. 2014 Light Spring Transmission Sensitivity without Q036 ................................. 5.1.3. 2012 Light Spring with Q036 ............................................................................... 5.1.4. 2014 Light Spring Transmission Sensitivity with Q036....................................... 5.1.5. 2012 Heavy Autumn EOR 10,500 MW without Q036......................................... 5.1.6. 2012 Heavy Autumn EOR 10,500 MW with Q036..............................................

5.2. Voltage Violations ........................................................................................................ 5.3. Short Circuit.................................................................................................................. 5.4. Mitigation...................................................................................................................... 5.5. Maximum Output Without Upgrades ...........................................................................

6. Cost Estimates....................................................................................................................... 7. Construction Time Estimate ................................................................................................. Appendix A - Case Attributes Appendix B - Voltage Violations Appendix C - Power Flow Plots Appendix D - Short Circuit Analysis

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1. Executive Summary The Interconnection Customer (IC), submitted a valid and complete Interconnection Request (IR) to Arizona Public Service Company (APS) for their proposed Wind Generation Project (Project). The Project is 500 MW net wind generation, located approximately 12 miles from and requesting interconnection to the Moenkopi 500 kV switching station. The proposed Commercial Operation Date (COD) is 01-01-2012. Interconnection Customer has requested Energy Resource (ER) interconnection service only. The Moenkopi 500 kV substation is the primary Point of Interconnection (POI). The Project is number 62 (Q062) in the APS generation interconnection queue. In accordance with Federal Energy Regulatory Commission (FERC) Large Generator Interconnection Procedures (LGIP), APS performed an Interconnection Feasibility Study (IFeS). The IFeS determined the following:

1. Preliminary identification of any thermal overload or voltage limits violations resulting from the interconnection.

2. Preliminary identification of any circuit breaker short circuit capability limits exceeded as a result of the interconnection.

3. Preliminary list of facilities, a non-binding good faith estimate of cost responsibility and a non-binding good faith estimated time to construct facilities necessary to interconnect the Project.

DISCLAIMER

Nothing in this report constitutes an offer of transmission service or confers upon the Interconnection Customer, any right to receive transmission service. APS and other interconnected utilities may not have the Available Transmission Capacity (ATC) to support the interconnection described in this report.

The Q062 Project was studied for 2012 Light Spring, 2014 Light Spring Transmission Sensitivity and 2012 Heavy Autumn East of River 10,500 MW scenarios, both with and without APS Project Q036 1,000 MW at Moenkopi 500 kV. The Project was studied with three different dispatch scenarios: to Arizona, to Arizona/California and to California to determine the impacts caused solely by the addition of Q062. For all scenarios that included APS Project Q036, the proposed mitigation plan of service for Q036 was also included. Without Q036, there are Category A normal and Category B emergency overloads caused solely by addition of Q062. The following system upgrades are required to mitigate all 2012 Light Spring, 2014 Light Spring transmission sensitivity, and 2012 Heavy Autumn EOR power flow violations without Q036.

1. Upgrade the Moenkopi - Eldorado (Eld) 500 kV Line series capacitors and conductor to 2300/3105 A 1991.9/2689.0 MVA

2. Upgrade the Navajo - Crystal 500 kV Line series capacitor to 2185/2950 A 1892.3/2554.8 MVA. With the upgrade of the C1 bank at Navajo in 2008, the Crystal series capacitor bank is the only unit requiring an upgrade.

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With Q036, there are Category A normal voltage violations and Category B emergency overloads caused solely by addition of Q062. The following system upgrades are required to mitigate all 2012 Light Spring, 2014 Light Spring transmission sensitivity, and 2012 Heavy Autumn EOR power flow violations with Q036.

1. Upgrade the Moenkopi - Eldorado 500 kV Line series capacitors and conductor to 2600/3500 A 2251.7/3031.1 MVA

2. Upgrade the Navajo - Crystal 500 kV Line series capacitors to 2500/3375 A 2165.1/2922.8 MVA

3. Add 200 MVAr voltage support at Eldorado 500 kV Project Q062 elected to be studied as an Energy Resource only. Under an “Energy Resource” interconnection, potential overloads may be mitigated through curtailment. To successfully mitigate the normal and post-contingency overloads identified in this study, significant curtailment of the 500 MW Project would be required. Without system reinforcements, Project Q062’s entire output may be fully curtailed depending on the system conditions and the dispatch scenario. For further discussion of these generation curtailments, see Section 5.5 “Maximum Output without Upgrades”. For this interconnection, long lead time to-build items are assumed to be the shunt capacitor and the series capacitor rebuild at 1.5 years each. Also since the work is done at separate sites, the work can be performed simultaneously. An unknown item with regards to construction time and impact upon Network Upgrade costs is the potential impact that this interconnection may face with regards to the Moenkopi-Eldorado 500kV line, whose conductor is presently sag-limited. (Please see *Note for Table 6.2 at the bottom of page 19.) Determination of the financial and time impacts upon the Project, if any, is anticipated to be available for the System Impact Study should the Interconnection Customer desire to move ahead in the interconnection process. A full discussion of this subject may be addressed at the Feasibility Study Results Meeting (yet to be scheduled).

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2. Study Assumptions The following general assumptions were used for this study:

1. The Project is 500 MW net wind generation, located approximately 12 miles from and interconnected to the Moenkopi 500 kV substation.

2. The proposed Commercial Operation Date (COD) is 01-01-2012 3. The IC has requested Energy Resource (ER) interconnection service 4. The IC has not selected wind turbines for this project but agreed to use GE 1.5 MW

doubly fed asynchronous generators (DFAG) for this study. The IC will need to select and provide appropriate steady-state, short circuit and dynamic modeling information in GE PSLF format for the actual wind turbines in order to proceed with the Interconnection System Impact Study (ISIS).

5. The generator tie line was modeled as 12 miles 3-1780 ACSR Chukar with a continuous rating of 4,359 A/3,775 MVA. The tower configuration was assumed to be horizontal with ~ 32 ft phase spacing and 1.5 ft equilateral conductor spacing. The positive sequence impedance of the line was modeled as R1pu=0.000098, X1pu=0.002565 and B1pu=0.233920.

6. 346 GE 1.5 MW DFAGs were modeled as one equivalent 519 MW generator with Qmax/Qmin = 251/-251 MVAr for a net output of 500 MW at Moenkopi 500 kV.

7. The individual unit step-up transformers were modeled as one equivalent 0.575/34.5 kV transformer rated at 605.5 MVA with 5.75% impedance at 605.5 MVA and X/R = 7.5. The main step-up transformer was modeled as one 34.5/500 kV transformer rated at 600 MVA with 15% impedance at 360 MVA.

8. The wind farm collector system was modeled as an equivalent 34.5 kV line section with positive sequence impedance R1pu=0.0065, X1pu=0.0261 and B1pu=0.1500. This assumed the use of both overhead and underground collector lines.

9. The Project was studied as an Energy Resource with: a. 500 MW scheduled to APS Metro Phoenix b. 250 MW scheduled to LADWP (55 MW)/SCE (195MW) and 250 MW scheduled

to APS Metro Phoenix c. 500 MW scheduled to LADWP (110 MW)/SCE (390 MW)

10. The preferred method to account for power injection is to reduce generation at one or more generating units in the area where the Project output is scheduled for delivery.

11. Regional transmission projects that will be operational by 2012 were modeled in the power flow cases.

Figure 2.1 shows a high level single line diagram of the Arizona transmission system in the vicinity of the Project. Figure 2.2 shows a detailed one-line of the proposed interconnected facilities at the Moenkopi 500 kV switching station.


Figure 2.1: Q062 Wind Generation Project Conceptual Single-Line Diagram

(to SCE Eldorado)

MOENKOPI500kV

WESTWING

FOURCORNERS

Project Q036(1000MW)

NAVAJO

(to Crystal)

(to Mead)

DUGAS

YAVAPAI

(from Palo Verde)

RED MESA

Project Q001 (1400 MW)

(345kV)

RACEWAY/TS9

(to Pinn. Peak)

(to Sun Valley)

Path 51 - Navajo South

Path 49 - East of River(partial)

(215 miles)

Project Q062 (500 MW)

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N

MoenkopiSwitching Station

EastWest

7/8/09BLK

Figure 2.2: Detailed one-line for the Moenkopi 500 kV switching station.


3. Power Flow Cases Six (6) pre-project power flow cases were developed using the power flow cases previously developed and used in APS’ Q040 IFeS:

1. 2012 Light Spring case 2. 2014 Light Spring transmission sensitivity (PV hub) case 3. 2012 Light Spring case with Q036 4. 2014 Light Spring transmission sensitivity (PV hub) case with Q036 5. 2012 Heavy Autumn East of River (EOR) case 6. 2012 Heavy Autumn East of River (EOR) case with Q036

The 2012 Light Spring power flow case is derived from the WECC 11lsp1sa.sav power flow case and represents light spring conditions in the 2011-2012 time frames. Due to recent changes to in service dates, the Devers-Palo Verde #2 500 kV Line, Palo Verde Hub-Sun Valley 500 kV and Hassyampa-North Gila #2 500 kV Line projects were modeled out of service in the 2012 Light Spring cases. These transmission projects were modeled in service as a sensitivity scenario for all Light Spring cases in the 2014 Light Spring cases. The Heavy Autumn East of River power flow case represents the 2010-2012 time frames with 10,500 MW of East of River (EOR) flow. The Heavy Autumn East of River (EOR) case modeled the Devers - Palo Verde #2 500 kV Line and Palo Verde Hub - Sun Valley 500 kV projects in service in order to asses the impacts to the future EOR path limit of 10,500 MW. The sensitivity cases with the APS Q036 1,000 MW at Moenkopi 500 kV project modeled included the 1,000 MW generator with output scheduled to California as an Energy Resource and the following proposed mitigation plan (Q036) of service:

1. Upgrade the Moenkopi-Eldorado 500 kV Line series capacitors and conductor to 2370/3200 A 2052.5/2771.3 MVA

2. Upgrade the Navajo - Crystal 500 kV Line series capacitors to 2300/3105 A 1991.9/2689.0 MVA

3. Add 200 MVAr voltage support at Eldorado 500 kV to maintain prescribed minimum voltage of 1.036 pu

The ratings of the Moenkopi-Eldorado 500 kV conductor were changed to 2480/2870 A 2147.7/2771.3 MVA. Fourteen (14) post-project power flow cases were developed from the pre-project cases by adding the Q062 project to the pre-project cases.

1. 2012 Light Spring case, with Q062 500 MW scheduled to APS Metro Phoenix 2. 2012 Light Spring case, with Q062 250 MW scheduled to LADWP (55 MW)/SCE

(195MW) and 250 MW scheduled to APS Metro Phoenix 3. 2012 Light Spring case, with Q062 500 MW scheduled to LADWP (110 MW)/SCE (390

MW)

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4. 2014 Light Spring transmission sensitivity case, with Q062 500 MW scheduled to APS

Metro Phoenix 5. 2014 Light Spring transmission sensitivity case, with Q062 250 MW scheduled to

LADWP (55 MW)/SCE (195MW) and 250 MW scheduled to APS Metro Phoenix 6. 2014 Light Spring transmission sensitivity case, with Q062 500 MW scheduled to

LADWP (110 MW)/SCE (390 MW) 7. 2012 Light Spring case with Q036, with Q062 500 MW scheduled to APS Metro Phoenix 8. 2012 Light Spring case with Q036, with Q062 250 MW scheduled to LADWP (55

MW)/SCE (195MW) and 250 MW scheduled to APS Metro Phoenix 9. 2012 Light Spring case with Q036, with Q062 500 MW scheduled to LADWP (110

MW)/SCE (390 MW) 10. 2014 Light Spring transmission sensitivity case with Q036, with Q062 500 MW

scheduled to APS Metro Phoenix 11. 2014 Light Spring transmission sensitivity case with Q036, with Q062 250 MW

scheduled to LADWP (55 MW)/SCE (195MW) and 250 MW scheduled to APS Metro Phoenix

12. 2014 Light Spring transmission sensitivity case with Q036, with Q062 500 MW scheduled to LADWP (110 MW)/SCE (390 MW)

13. 2012 Heavy Autumn East of River (EOR) case, with Q062 500 MW scheduled to APS Metro Phoenix

14. 2012 Heavy Autumn East of River (EOR) case with Q036, with Q062 500 MW scheduled to APS Metro Phoenix

The attributes for all the pre and post-project cases are summarized in Appendix A.

4. Study Methodology This IFeS consists of power flow and short circuit studies in order to identify a preliminary list of facilities, a non-binding good faith estimate of cost responsibility and a non-binding good faith estimated time to construct facilities necessary to interconnect the projects in the cluster.

4.1. Post-Transient Governor Power Flow Analysis For normal (pre-disturbance) conditions, automatic transformer taps (TCULs), static VAr devices (SVDs) and phase-shifting transformers (PSTs) will be allowed to adjust in solving the power flow cases. All transmission facility loadings must be below normal continuous ratings. Transmission bus voltages must be maintained between 0.95 per unit and 1.05 per unit. Post-project bus voltages at Pinnacle Peak, Kyrene and Devers 230 kV buses shall not deviate by more than 5% from the pre-project bus voltages. Sufficient transmission capacity will be provided without relying on or unduly imposing upon any other utility’s transmission system. The transmission system will not result in an adverse impact on other major WECC path flow limits. Post-transient governor power flow analysis was performed using the NERC/WECC planning standards. Power flow analysis was used to evaluate thermal and voltage performance of the transmission system for NERC/WECC Category A normal (all elements

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in-service) conditions, NERC/WECC Category B emergency (one element out of service) conditions and NERC/WECC Category C (two or more elements out of service) conditions. Category A (N-0) normal overloads are those that exceed 100% of normal ratings that occur with all facilities in service. Category B/C emergency overloads are those that exceed 100% of emergency ratings that occur due to Category B/C contingencies. The post-transient governor power flow solution (post-disturbance) parameters are as follows:

1. Area Interchange Control Disabled 2. Governor blocking: Enabled using baseload flag 3. DC Converter Control: Enabled 4. Automatic Phase Shifter Control: Disabled 5. Transformer Tap Adjustment: Disabled 6. Automatic SVD Control: Disabled 7. Generator Voltage Remote Control: Remote-regulating units will be reset to

regulate their terminal bus at the pre-disturbance voltage. (Except Palo Verde #1-#3 ) Reported normal thermal loading will be limited to the condition where a modeled transmission component was loaded above 100% of the normal MVA rating (Rating 1 as entered in the power flow case), and the incremental increase in component loading, between pre-project and post-project, exceeded 1%. Reported emergency thermal loading will be limited to the condition where a modeled transmission component was loaded over 90% of its appropriate emergency MVA rating (Rating 2 as entered in the power flow case), and the incremental increase in component loading, between pre-project and post-project, exceeded 1%. Reported normal voltage violations will be limited to the conditions where per unit (pu) voltages are less than 0.95 or greater than 1.05. Reported emergency voltage violations will be limited to the conditions where per unit voltages are less than 0.90 or greater than 1.10. In addition, only voltage deviations greater than 5% between the pre and post-contingency and a 1% increase in voltage deviation between the pre and post-project power flow cases will be recorded for NERC/WECC Category B outages and only voltage deviations greater than 10% between the pre and post-contingency and a 1% increase in voltage deviation between the pre and post-project power flow cases will be recorded for NERC/WECC Category C outages. Note: in some instances, resulting local circuit overloads and/or voltage deviations may be deemed acceptable per local criteria, as long as the local system’s post-contingency performance does not result in cascading outages. The Western Arizona Transmission System Task Force (WATS) bus voltage criterion as shown in Table 4.1 was also used as a flagging tool for potential voltage violations.

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Table 4.1 WATS Voltage Criteria

Bus Pre-Outage Min. Volt (p.u.) Post-Disturbance Min. Volt (p.u.) Adelanto 500kV Flag if < 1.025 0.95 Sylmar 230kV Flag if < 0.99 0.95 LADWP 1.00 0.95 Mead 230kV 0.95 0.95 NPCO 230kV Flag if < 0.985 0.90 NPCO 500kV Flag if < 500kV(1.0) 488kV(.976) Palo Verde 500kV 525kV(1.05) 525kV(1.05) SCE 230kV Flag if < 0.95 0.90 SCE 500kV Flag if < 1.036 0.966 SDG&E 230kV 0.95 0.90 SDG&E 500kV 0.998 0.945 North Gila 500kV (1.0 pu) 500kV (1.0 pu) Westwing 230kV Flag if < 1.03 0.95 Blythe 161kV Flag if < 0.95 0.91 MWD Flag if < 0.9875 0.95 Arizona 230 kV 1.00 0.95 Arizona 500 kV 1.05 1.00 Post-transient governor power flow analysis was performed on all pre-project and post-project cases. Table 4.2 shows the contingencies that were considered in this study. Table 4.2 Selected NERC/WECC Category B and C Contingencies NERC/WECC Category B Contingencies (G-1) Tripping of one Navajo unit (G-1) Tripping of one Palo Verde unit Navajo-RME 500 kV Line RME-Moenkopi 500 kV Line Navajo-Dugas 500 kV Line Dugas-Raceway 500 kV Line Raceway-Westwing 500 kV Line Moenkopi-Yavapai 500 kV Line Yavapai-Westwing 500 kV Line Eldorado-Lugo 500 kV Line Four Corners-Moenkopi 500 kV Line Four Corners-Q001 500 kV Line Q001-RME 500 kV Line Navajo-Crystal 500 kV Line Crystal-McCullough 500 kV Line Palo Verde-Westwing #1 500 kV Line Palo Verde-Devers 500 kV Line Hassayampa-North Gila 500 kV Line Perkins-Mead 500 kV Line Moenkopi-Eldorado 500 kV Line Delany-Devers 500 kV Line NERC/WECC Category C Contingencies G-2 Simultaneous loss of 2 Palo Verde units IPP DC Line Outage Moenkopi-Yavapai and Navajo-Dugas 500 kV Lines Yavapai-Westwing and Navajo-Dugas 500 kV Lines Palo Verde-Devers and Delany-Devers 500 kV Lines

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4.2. Short Circuit Analysis Short circuit analysis was performed to determine the maximum fault currents on buses in the vicinity of the Project. This study assessed the impact of increased fault duty resulting from the Project for single line-to-ground and three-phase faults. Equipment that may become over-stressed as a result of the added generation was identified if the fault duty exceeds 100% of its applicable interrupting capability.

5. Study Results

5.1. Thermal Overloads Post-transient governor power flow analysis was performed on all pre and post-project power flow cases. The results were compared to determine the impacts caused solely by the addition of the cluster projects and to identify the system reinforcements necessary to mitigate the adverse impacts.

5.1.1. 2012 Light Spring without Q036 Power flow analysis was performed on the 2012 Light Spring pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts. The Moenkopi-Eldorado 500 kV series capacitors have both Category A and Category B post-project overloads. The Moenkopi-Eldorado 500 kV conductor and the Navajo-Crystal 500 kV series capacitors have Category B post-project overloads. Table 5.1 summarizes the overloads for 2012 Light Spring conditions without Q036.

Table 5.1: Thermal Overload Summary 2012 Light Spring without Q036

Pre-Project Post-Project to AZ Post-Project to AZ/CA Post-Project to CA Monitored Element Rating (Amps) Amps % Amps % Amps % Amps %

Base Case (All Facilities In Service) Moenkopi-Eldorado 500 kV Series Caps 1 1900 1758 93 1868 98 1915 101 1962 103 Moenkopi-Eldorado 500 kV Conductor 2480 1758 71 1868 75 1915 77 1962 79 Moenkopi-Eldorado 500 kV Series Caps 2 1900 1758 93 1868 98 1915 101 1962 103 Navajo-Crystal 500 kV Series Caps 1 2200 1843 84 1898 86 1937 88 1979 90 Navajo-Crystal 500 kV Conductor 3696 1843 50 1898 51 1937 52 1979 54 Navajo-Crystal 500 kV Series Caps 2 2037 1843 90 1898 93 1937 95 1979 97 Navajo-Crystal 500 kV SLO Moenkopi-Eldorado 500 kV Series Caps 1 2750 2636 96 2774 101 2840 103 2907 106 Moenkopi-Eldorado 500 kV Conductor 2870 2636 92 2774 97 2840 99 2907 101 Moenkopi-Eldorado 500 kV Series Caps 2 2750 2636 96 2774 101 2840 103 2907 106 Moenkopi-Eldorado 500 kV SLO Navajo-Crystal 500 kV Series Caps 1 2970 2613 88 2717 91 2777 94 2840 96 Navajo-Crystal 500 kV Conductor 4714 2613 55 2717 58 2777 59 2840 60 Navajo-Crystal 500 kV Series Caps 2 2750 2613 95 2717 99 2777 101 2840 103

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5.1.2. 2014 Light Spring Transmission Sensitivity without Q036 Power flow analysis was performed on the 2014 Light Spring transmission sensitivity pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts. There were no Category A, B or C thermal overloads for any of the post-project cases. Table 5.2 summarizes the overloads for 2014 Light Spring transmission sensitivity conditions without Q036.

Table 5.2: Thermal Overload Summary 2014 Light Spring Transmission Sensitivity without Q036



5.1.3. 2012 Light Spring with Q036 Power flow analysis was performed on the 2012 Light Spring with Q036 pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts. The Moenkopi-Eldorado 500 kV series capacitors, Moenkopi-Eldorado 500 kV conductor and the Navajo-Crystal 500 kV series capacitors have Category B post-project overloads. Table 5.3 summarizes the overloads for 2012 Light Spring conditions with Q036.

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Table 5.3: Thermal Overload Summary 2012 Light Spring with Q036



5.1.4. 2014 Light Spring Transmission Sensitivity with Q036 Power flow analysis was performed on the 2014 Light Spring transmission sensitivity with Q036 pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts.

There were no Category A, B or C thermal overloads for any of the post-project cases. Table 5.4 summarizes the overloads for 2014 Light Spring transmission sensitivity conditions with Q036.

Table 5.4: Thermal Overload Summary 2014 Light Spring Transmission Sensitivity with Q036



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5.1.5. 2012 Heavy Autumn EOR 10,500 MW without Q036 Power flow analysis was performed on the 2012 Heavy Autumn EOR 10,500 pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts. The Moenkopi-Eldorado 500 kV series capacitors have post-project Category A normal overloads. The Moenkopi-Eldorado 500 kV series capacitors, Moenkopi-Eldorado 500 kV conductor and the Navajo-Crystal 500 kV series capacitors have Category B pre and post-project overloads. There were no Category A, B or C thermal overloads for any of the post-project cases. Table 5.5 summarizes the overloads for 2012 Heavy Autumn EOR 10,500 MW conditions without Q036.

Table 5.5: Thermal Overload Summary 2012 Heavy Autumn EOR 10,500 MW without Q036

Pre-Project Post-Project to AZ Monitored Element Rating (Amps) Amps % Amps %

Base Case (All Facilities In Service) Moenkopi-Eldorado 500 kV Series Caps 1 1900 1881 99 1983 104 Moenkopi-Eldorado 500 kV Conductor 2480 1881 76 1983 80 Moenkopi-Eldorado 500 kV Series Caps 2 1900 1881 99 1983 104 Navajo-Crystal 500 kV Series Caps 1 2200 1863 85 1913 87 Navajo-Crystal 500 kV Conductor 3696 1863 50 1913 52 Navajo-Crystal 500 kV Series Caps 2 2037 1863 91 1913 94 Navajo-Crystal 500 kV SLO Moenkopi-Eldorado 500 kV Series Caps 1 2700 2865 106 2988 111 Moenkopi-Eldorado 500 kV Conductor 2870 2865 100 2988 104 Moenkopi-Eldorado 500 kV Series Caps 2 2750 2865 104 2988 109 Moenkopi-Eldorado 500 kV SLO Navajo-Crystal 500 kV Series Caps 1 2970 2777 94 2867 97 Navajo-Crystal 500 kV Conductor 4714 2777 59 2867 61 Navajo-Crystal 500 kV Series Caps 2 2750 2777 101 2867 104

5.1.6. 2012 Heavy Autumn EOR 10,500 MW with Q036 Power flow analysis was performed on the 2012 Heavy Autumn EOR 10,500 MW with Q036 pre and post-project cases. The results were compared to determine the impacts caused solely by the addition of Q062 and to identify the system reinforcements necessary to mitigate the adverse impacts. There were no Category A normal overloads for the post-project case. The Moenkopi-Eldorado 500 kV series capacitors and Moenkopi-Eldorado 500 kV conductor have Category B post-project overloads. Table 5.6 summarizes the overloads for 2012 Heavy Autumn EOR 10,500 MW conditions with Q036.

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Table 5.6: Thermal Overload Summary 2012 Heavy Autumn EOR 10,500 MW with Q036

Pre-Project Post-Project to AZ Monitored Element Rating (Amps) Amps % Amps %

Base Case (All Facilities In Service) Moenkopi-Eldorado 500 kV Series Caps 1 2370 2084 88 2184 92 Moenkopi-Eldorado 500 kV Conductor 2480 2084 84 2184 88 Moenkopi-Eldorado 500 kV Series Caps 2 2370 2084 88 2184 92 Navajo-Crystal 500 kV Series Caps 1 2300 1963 85 2013 88 Navajo-Crystal 500 kV Conductor 3696 1963 53 2013 54 Navajo-Crystal 500 kV Series Caps 2 2300 1963 85 2013 88 Navajo-Crystal 500 kV SLO Moenkopi-Eldorado 500 kV Series Caps 1 3200 3108 97 3230 101 Moenkopi-Eldorado 500 kV Conductor 3200 3108 97 3230 101 Moenkopi-Eldorado 500 kV Series Caps 2 3200 3108 97 3230 101 Moenkopi-Eldorado 500 kV SLO Navajo-Crystal 500 kV Series Caps 1 3105 2957 95 3048 98 Navajo-Crystal 500 kV Conductor 4714 2957 63 3048 65 Navajo-Crystal 500 kV Series Caps 2 3105 2957 95 3048 98

5.2. Voltage Violations The WATS voltage criterion in Table 4.1 was used to screen for low voltages throughout the region. The base case voltage at Eldorado 500 kV is less than its prescribed limit for 2012 Light Spring with Q036 post-project cases with at least 250 MW of generation dispatched to California. Voltage support is required to boost the post-project voltage at Eldorado to at least 1.036 pu. This voltage support is in addition to the 200 MVAr of voltage support that is assumed to be part of the Q036 mitigation plan of service for a total of 400 MVAr at Eldorado 500 kV. For all pre and post-project 2012 Light Spring cases, there are low voltages at LADWP’s Intermountain and McCullough 230 kV, WALC’s Gila, North Gila East, and North Gila West 230 kV, WALC’s Navajo/Longhouse/Glen Canyon PS 230 kV and MWD’s EAGLEMTN and J.HINDS 230 kV buses. For all pre and post-project 2014 Light Spring cases, there are low voltages at LADWP’s Intermountain 230 kV and WALC’s Navajo/Longhouse/Glen Canyon PS 230 kV buses. Since these voltage violations occur in the both the pre and post-project cases Q062 is not responsible for mitigating these voltage violations. For 2012 Light Spring cases without Q036, there are Nevada 230 kV bus voltages (WESTSIDE, DECATUR) lower than their prescribed limits when the Q062 500 MW is dispatched to California. For 2012 and 2014 Light Spring pre and post-project cases with Q036, there are Nevada 230 kV bus voltages (WESTSIDE, DECATUR, MCDONALD, SINATRA, AVERA) lower than their prescribed limits. The voltages in the Nevada 230 kV area are related to the amount of power dispatched from Arizona to California. Since these voltages are very near their prescribed limits or below their prescribed limits in all the pre-projects cases, Q062 is not responsible for mitigating these voltage violations.

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There are several Arizona 500 kV voltages (Four Corners/Yavapai/Mead) that are lower than their prescribed limits in both the pre and post-project cases. By adjusting voltage schedules in the Four Corners area and adjusting the Yavapai 500/230 kV transformer taps these voltages were increased to greater than their prescribed limit of 1.05 pu. These changes to the system were verified to eliminate the voltage violations as part of the Q062 mitigation testing both with and without Q036. There were no contingency voltage or voltage deviation violations for any scenarios studied. Complete listings of all voltage violations are included in Appendix B and selected power flow plots are included in Appendix C. All power flow analysis was conducted with version 16.0_11 of General Electric’s PSLF/PSDS/SCSC software.

5.3. Short Circuit No equipment short circuit ratings in the vicinity of the cluster projects were exceeded as a result of the projects. Single line-to-ground (SLG) and three-phase faults were simulated with and without the cluster projects to determine if there are any overstressed circuit breakers caused by addition the cluster projects. Study results indicate there are no circuit breaker fault duty limit violations attributable to the Project. The IC’s are not responsible for mitigating any pre-existing overstressed circuit breakers. The short circuit analysis results are included in Appendix D.

5.4. Mitigation Plans of service were developed to mitigate all criteria violations for all post-project scenarios. Without Q036, the following system upgrades are required to mitigate all 2012 Light Spring, 2014 Light Spring transmission sensitivity, and 2012 Heavy Autumn EOR power flow violations.

1. Upgrade the Moenkopi - Eldorado 500 kV Line series capacitors and conductor to 2300/3105 A 1991.9/2689.0 MVA

2. Upgrade the Navajo - Crystal 500 kV Line series capacitors to 2185/2950 A 1892.3/2554.8 MVA at Crystal. Navajo series cap upgraded in 2008 to 2248 A.

With Q036, the following system upgrades are required to mitigate all 2012 Light Spring, 2014 Light Spring transmission sensitivity, and 2012 Heavy Autumn EOR power flow violations. 3. Upgrade the Moenkopi - Eldorado 500 kV Line series capacitors and conductor to

2600/3500 A 2251.7/3031.1 MVA 4. Upgrade the Navajo - Crystal 500 kV Line series capacitors to 2500/3375 A

2165.1/2922.8 MVA

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5. Add 200 MVAr voltage support at Eldorado 500 kV

5.5. Maximum Output Without Upgrades The maximum output without upgrades was determined for each of the post-project cases as an alternative to transmission system upgrades. Table 5.7 shows the maximum output without upgrades for all scenarios without Q036.

Table 5.7: Maximum Output without Upgrades without Q036

12lsp post-project 14lsp post-project Without Q036 AZ AZ/CA CA AZ AZ/CA CA

12ha eor post-

project Cat A Limiting Element Moenkopi-Eldorado 500 410 310 500 500 500 0 Navajo-Crystal 500 500 500 500 500 500 0 Cat B Limiting Element Moenkopi-Eldorado 430 300 160 500 500 500 0 Navajo-Crystal 500 300 175 500 500 500 0 Maximum (MW) 430 300 160 500 500 500 0

There are pre-project overloads for the 2012 Heavy Autumn EOR 10,500 MW without Q036, therefore the maximum output without upgrades is 0 MW for this scenario. Table 5.8 shows the maximum output without upgrades for all scenarios without Q036. Table 5.8: Maximum Output without Upgrades with Q036

12lsp post-project 14lsp post-project With Q036 AZ AZ/CA CA AZ AZ/CA CA

12ha eor post-

project Cat A Limiting Element Moenkopi-Eldorado 500 500 500 500 500 500 500 Navajo-Crystal 500 500 500 500 500 500 500 Cat B Limiting Element Moenkopi-Eldorado 150 125 20 500 500 500 425 Navajo-Crystal 275 125 20 500 500 500 500 Maximum (MW) 150 125 20 500 500 500 425

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6. Cost Estimates Mitigation and costs listed here are grouped into two parts: 1) direct assignment costs, which includes basic costs for the interconnection itself, and 2) cost of system reinforcements required to allow the full dispatch of the Project’s 500 MW. A high-level, good faith, non-binding cost estimate for this required transmission work is as follows: Table 6.1: Estimated Direct Assignment Costs

Estimated CostMoenkopi 500 kV Termination $2,300,000

Total $2,300,000 The cost estimates for mitigation without Q036 are listed below. The costs do not include any costs for new rights-of-way that may potentially be needed for some upgrades. For the Project’s connection to the Moenkopi 500 kV bus, additional reinforcements are required to allow the Project’s full 500 MW output. Specifically, this IFeS identified a need to upgrade the following equipment: Table 6.2: Network Upgrade costs and equipment ratings for Q062 w/ and w/o Q036

Existing system w/o Q036 w/ Q036 Q062 w/o Q036 Q062 w/ Q036 Moen-Eld Series Caps

1900/2750 A(2) 2370/3200 A 2300/3105 A $18 M (2) 2600/3500 A $4 M (2)

Nav-Crystal Series Caps

2037/2750 A(1) 2300/3105 A 2185/2950 A $9 M (1) 2500/3375 A $4 M (2)

Conductor upgrade

2480/2870 A 2370/3200 A * *

Reactive additions

200 Mvar @ Eldorado

200 Mvar @ Eldorado

$ 2.5 M

Total $27 M + * $10.5 M + * In addition, increased emergency capability is required for the Moenkopi-Eldorado 500kV line, whose conductor is presently sag-limited. However in 2008 the line was surveyed to the California border for vegetation management purposes. The clearance data collected can be converted into a model for line rating purposes and subsequently the line capability can be evaluated. At this point, the data has not been converted and the line ratings have not been evaluated.

* Note: Conductor upgrades may be required for the Moenkopi-Eldorado 500 kV line. As of the date of publishing of this Feasibility Report, no accurate data exists to make a reasonable determination of the need for this requirement and therefore, APS is unable to

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supply an estimated cost. Note that work is proceeding on a higher queued project which could eventually lead to a determination and estimated costs. APS’s anticipation is that this information could be available during the System Impact Study, should this higher queued Interconnection Customer choose to proceed in the interconnection process, and the higher queued project remains in the process. This may be discussed at the Feasibility Study Results Meeting.

APS typically repays the costs of Network Upgrades via transmission credits, however may choose, on a case-by-case basis, to repay these costs financially over the twenty year allowable FERC term. APS also reserves the right to repay Network Upgrades early without penalty. This subject may be discussed at the Feasibility Study Results Meeting (yet to be scheduled).

7. Construction Time Estimate Long lead time items are estimated to be either the completed rebuild of the series capacitors or the shunt capacitor at 1.5 years each. Since most of the work is at separate sites, construction times are assumed to be simultaneous. However, potential upgrades to the Moenkopi-Eldorado line are still unknown and construction times for this item are therefore not included in this estimate.

1. Executive Summary2. Study Assumptions3. Power Flow Cases4. Study Methodology4.1. Post-Transient Governor Power Flow Analysis4.2. Short Circuit Analysis

5. Study Results5.1. Thermal Overloads5.1.1. 2012 Light Spring without Q0365.1.2. 2014 Light Spring Transmission Sensitivity without Q0365.1.3. 2012 Light Spring with Q0365.1.4. 2014 Light Spring Transmission Sensitivity with Q0365.1.5. 2012 Heavy Autumn EOR 10,500 MW without Q0365.1.6. 2012 Heavy Autumn EOR 10,500 MW with Q036

5.2. Voltage Violations5.3. Short Circuit5.4. Mitigation5.5. Maximum Output Without Upgrades

6. Cost Estimates7. Construction Time Estimate

a subsidiary of pinnacle west capital corporation · 2009. 9. 16. · cost estimates ... (to mead)...

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