Q87 Generation Interconnection

Transcription

1 A subsidiary of Pinnacle West Capital Corporation Version 1.0 Q87 Generation Interconnection Interconnection Facilities Study APS Contract No By Arizona Public Service Company Transmission Planning June 6, 2011

2 FACILITIES STUDY Q87 PROPOSED GENERATION TABLE OF CONTENTS 1. Introduction Study Results Power Flow Voltage Flicker Transient Analysis Post-transient Governor Power Flow Analysis Cost Estimates Summary of Cost and Construction Time Estimates Network Upgrades Transmission Provider s Interconnection Facilities System Reinforcements Power Factor Requirements... 8 LIST OF APPENDICES Appendix A Select Power Flow Plots Appendix B Transient Stability Modeling Appendix C Transient Stability Plots Appendix D Construction Schedule Details Appendix E Cotton Center Substation One-Line Diagram Page 2

3 1. Introduction APS performed this Generator Interconnection Facilities Study (FaS) in response to a valid generator interconnection request by the Interconnection Customer (IC). The IC is listed in APS s Active Generator Interconnection Queue as Queue Position 87. The purpose of this study is to provide cost and construction schedule estimates for the facilities needed to interconnect the IC s proposed 20 MW photovoltaic solar generation facility (Q87) located near Gila Bend, Arizona in Maricopa County. The Point of Interconnection (POI) requested for the FaS is the APS Cotton Center 69kV substation. The proposed Commercial Operation Date for Q87 is December 31, 2011 with generator testing beginning October 1, This IC has already completed a System Impact Study (SIS). The Interconnection Customer has chosen to interconnect as an Energy Resource Interconnection Service (Energy Resource). Delivery of the Q87 output beyond the POI would be on an as-available basis only. The delivery of the Q87 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. Figure 1 below shows a general depiction of the 69 kv system around Q87 s proposed POI. Figure 1: Project Location and 69kV System Page 3

4 2. Study Results 2.1. Power Flow 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 Project and to identify the system reinforcements necessary to mitigate the adverse impacts. These Pre-Project and Post-Project cases were evaluated for Category A (N-0 or all lines in service) conditions. Then approximately 60 Category B and 2 Category C contingencies were applied to the cases. Areas 14 (Arizona) and 73 (WAPA R.M.) were monitored. Voltage results focused on buses at 69 kv and above, as well as all Project buses. Select power flow plots are included in Appendix A. Since the System Impact Study (SIS) was completed for Q87, there are three planned changes that affect the flows near the Project's interconnection: 1) Q31 has delayed its In-Service Date from 2011 to 2013, 2) a 12 kv generator will interconnect to the County Line Substation prior to this Project, and 3) two 12 kv generators will interconnect to the Cotton Center Substation prior to this Project. These planned changes have been modeled and were used in the analysis. The results of the 2011, 2013 and 2014 power flow analyses indicate the Project triggered one new overload in the monitored systems of Arizona and WAPA R.M are shown below. The results are shown below. 1 Table 2.1: 2011 N-1 Overloads Emergency Monitored Branch Contingency Description Rating (Amps) GILLESPI-COTN CTR 69 kv % Emergency Rating Pre Post N-1 JOJOBA-KYRENE 500KV N-1 PALOVRDE-RUDD 500KV N-1 BUCKEYE 230/69KV XFMR N-1 SADDLE MTN-BUCKEYE 69kV N-1 SADDLEMT-CNTYLINE 69 kv There is an existing plan to upgrade the Cotton Center-Gillespie 69 kv line in 2013 as a network upgrade assigned to a higher queued project: Q63. Unfortunately, due to permitting issues and construction schedules, the earliest In-Service Date for the Cotton Center-Gillespie 69 kv rebuild is Therefore, Q87 will need to phase their project, and will be limited to an output of 5 MW (98% loading) until the rebuild can be completed in In the event that Q63 drops from APS s Interconnection Queue, Q87 will be responsible for all costs associated with rebuilding the Cotton Center-Gillespie 69 kv line. Voltage N-0 The power flow results showed no Project caused N-0 voltage violations. Voltage N-1 and N-2 The power flow results showed no Project caused N-1 or N-2 voltage violations. 1 Though not Project-related, in 2014 the Palo Verde-Delany 500 kv outage causes the case solution to diverge without the applicable SPS, opening the Hassayampa Tap-Hassayampa Pump 230 kv line and/or tripping nearby generation. Detailed discussion is not part of this report. Page 4

5 2.2. Voltage Flicker The results found no Project caused voltage flicker deviations greater than 1.5%. Table 2.2: 2011 Voltage Flicker 100% Generation (base) 10% Generation 30% Generation 60% Generation 90% Generation Bus Volt (pu) Volt (pu) Deviation (%) Volt (pu) Deviation (%) Volt (pu) Deviation (%) Volt (pu) Deviation (%) Q kV % % % % CNTYLINE 69.00kV % % % % AZTEC 69.00kV % % % % HORN 69.00kV % % % % SADDLEMT 69.00kV % % % % BUNYAN 69.00kV % % % % PALOMA 69.00kV % % % % GILABEND 69.00kV % % % % PVNGPUMP 69.00kV % % % % BUCKEYE 69.00kV % % % % 2.3. Transient Analysis The results of the 2011 transient stability analysis indicate the Project did not trigger any transient stability violations. See Appendix B for the Transient Stability Modeling and Appendix C for select Transient Stability Plots Post-transient Governor Power Flow Analysis The results of the 2011 post-transient governor power flow analysis indicate the Project did not trigger any voltage deviation violations. Page 5

6 3. Cost Estimates 3.1. Summary of Cost and Construction Time Estimates Table 3.1 below provides a summary of which costs are considered Network Upgrades and which are Transmission Provider s Interconnection Facilities. The work involved for each category is described in more detail in sections 3.2 and 3.3 below. Table 3.1: Q87 Project Cost Summary Network Transmission Provider's Upgrades Interconnection Facilities Cotton Center 69kV Ring Bus $1,616,000 $201,000 69kV Line Work (GB-GP In & Out) $307,000 - Communications - $70,000 Land Acquisition $15,000 - Subtotal $1,938,000 $271,000 Grand Total $2,209,000 Total Cost for Q87 (if Q86 is In-Service) $1,240,000 The costs shown above in Table 3.1 show the total cost to expand Cotton Center substation assuming Q86 is interconnected (6-element ring instead of 5-element). The specific costs for Q87 would be half of the Network Upgrades ($969k), plus the Q87 Transmission Provider s Interconnection Facilities ($271k). The Interconnection Customer s desired In-Service Date for the Interconnection Facilities is December 31, The provided construction schedule used an estimated start date of May 1, The actual construction start date would occur when the Interconnection Customer provides written authorization to proceed, provided all interconnection agreements and funding arrangements are in place. Table 3.2 below provides a summary of the construction schedules. Additional schedule details can be found in Appendix D. Table 3.2: Construction Time Estimates Facility Schedule Cotton Center 69kV Ring Bus 9 months Cotton Center 69kV Ring Bus (TPIF) 9 months 69kV Line Work (GB-GP In & Out) 7 months Total 9 months *Substation and line rebuild work can be completed in parallel with each other The summary provided in Table 3.2 above shows a total estimated completion time of 9 months from the actual construction start date. Therefore, the desired In-Service Date of December 31, 2011 cannot be met. APS and the Interconnection Customer must therefore discuss and mutually agree to a new and acceptable projected In-Service Date. Please note that the Commercial Page 6

7 Operation Date must be within the ten (10) year transmission planning period from the date of the valid Interconnection Request Network Upgrades New solar generation at Cotton Center Substation will be coming online this summer. Due to the addition of this generation, the Cotton Center substation will need to be upgraded from a single tap to an in and out (two 69 kv line breakers). The two solar projects are expected to be In-Service by July 15, The Network Upgrades for the Q87 project consist of expanding APS s Cotton Center 69 kv substation from a 5-element ring bus, to a 6-element ring bus. This expansion also involves rebuilding and relocating some overhead 69 kv and 12 kv lines to bring the Gila Bend-Gillespie 69 kv line in and out of the Cotton Center substation. A one-line of the Cotton Center ring bus can be seen in Appendix E (Network Upgrades shown in red). The new ring bus will require expanding the Cotton Center substation approximately one (1) acre to the south. The costs associated with acquiring the land for the substation expansion are included in the estimates. The Network Upgrade costs shown in Table 3.1 above are considered shared costs, which would be shared with Q86 (assuming Q86 is still interconnecting into the Cotton Center Substation). If more projects interconnect into Cotton Center, each project s share of the Network Upgrades would be recalculated. All of these costs are considered Network Upgrades, which are typically repaid to the Interconnection Customer, per FERC rules, as transmission credits over a maximum of twenty (20) years. The assumptions used for all cost estimates are as follows: Rebuilds are assumed that lines will be rebuilt in existing location Access and lay down yards are not included in the estimate Rough grading costs are not included in the estimate 120 x120 minimum space required for control house (drainage may require additional land) APS will construct, own and operate the facilities in the Cotton Center substation and the portion of 69 kv line from the Cotton Center 69 kv bus up to the first structure outside the substation fence The IC will construct, own and maintain the 69 kv generation tie-line from the first structure outside the switchyard fence to the Q87 site The IC will be responsible for providing a fiber optic communications path from the Q87 facility to the Cotton Center substation All estimates are in 2011 dollars 3.3. Transmission Provider s Interconnection Facilities The Transmission Provider s Interconnection Facilities required for the Q87 project include the necessary switches, breakers, bus work, etc needed to bring the Q87 69 kv generation tie-line into the Cotton Center substation. The facilities are shown in blue in Appendix E. The communication costs are also considered TPIF, which includes all necessary equipment as well as any work to terminate the IC s fiber line from the Q87 site to the Cotton Center substation. These costs are the sole responsibility of the Interconnection Customer, and will not be reimbursed. Page 7

8 4. System Reinforcements The Interconnection Customer has chosen to interconnect as an Energy Resource, with delivery of the Q87 output beyond the POI on an as-available transmission basis only, using firm and non-firm transmission capacity that may be available when a transmission service request is made. The Q87 project triggered the rebuild of the Cotton Center-Gillespie 69 kv line in 2011 (during the SIS), which is a Network Upgrade to the APS Transmission System. Due to permitting and schedule limitations, the rebuild cannot be completed until Therefore, Q87 will need to phase their project, and will be limited to an output of 5 MW until the rebuild can be completed in Power Factor Requirements The APS Open Access Transmission Tariff (OATT) policy regarding power factor requires all Interconnection Customers, with the exception of wind generators, to maintain an acceptable power factor (typically near unity) at the Point of Interconnection (POI), subject to system conditions. The APS OATT also requires Interconnection Customers to be able to achieve +/ power factor at the POI, with the maximum "full-output" VAr capability available at all outputs. Furthermore, APS requires Interconnection Customers to have dynamic voltage control and maintain the voltage as specified by the transmission operator within the limitation of +/ power factor, as long as the Project is online and generating. If the Project s equipment is not capable of this type of response, a dynamic reactive device will be required. APS has the right to disconnect the Project if system conditions dictate the need to do so in order to maintain system reliability. Page 8

9 Appendix A Construction Schedule Details Select Power Flow Plots Plot Listing: Page 9

10 Page 10

11 Page 11

12 Page 12

13 Page 13

14 Page 14

15 Appendix B Q87 Transient Stability Modeling Page 15

16 Plant Dynamic Model Data utilizing Emerson PV Inverters Input Parameters: Emerson Inverters Q087 Constant Description From IC rsrc Generator source resistance, pu on plant base 0.00 xsrc Generator source reactance, pu on plant base 0.00 Vratio Ratio of PV array open circuit to peak power voltage 1.25 Iratio Ratio of PV array short circuit to peak power current 1.05 Tdc Inverter DC capacitor bank time constant, sec Itlim Inverter AC thermal current limit, pu on plant base 1.00 Ixlim Inverter AC transient active current limit, pu on plant base 1.45 Iylim Inverter AC transient reactive current limit, pu on plant base 1.00 Kpdc DC voltage regulator proportional gain 7.65 Kidc DC voltage regulator integral gain 0.29 Kpac AC voltage regulator proportional gain 1 Kiac AC voltage regulator integral gain 0.5 QMOD Reactive power mode (0 = constant reactive current, 1 = constant reactive power, 2 = constant power factor, 3 = voltage regulation) TQT Reactive power transducer time constant, sec 0.2 TQR Reactive power regulator time constant, sec 0.4 TSC AC voltage regulator communications delay, sec 1 OV1L Overvoltage trip point #1, pu 1.36 OV1T Overvoltage delay #1, sec OV2L Overvoltage trip point #2, pu 1.20 OV2T Overvoltage delay #2, sec 0.16 OV3L Overvoltage trip point #3, pu 1.10 OV3T Overvoltage delay #3, sec 1.00 UV1L Undervoltage trip point #1, pu 0.50 UVIT Undervoltage delay #l, sec 0.16 UV2L Undervoltage trip point #2, pu 0.88 UV2T Undervoltage delay #2, sec 2.00 OFL Overfrequency trip point, pu 60.5 OFT Overfrequencv delay, sec 1.00 UF1L Underfrequency trip point #1, pu 57.0 UF1T Underfrequency delay #1, sec 0.16 UF2L Underfrequency trip point #2, pu 59.8 UF2T Underfrequency delay #2, sec Page 16

17 Appendix C Q87 Transient Stability Plots Page 17

18 Transient Stability Analysis was run on each of the contingencies listed in the table below. This appendix includes a sampling of the plots that were created, which are highlighted in grey. Plots for the remaining contingencies may be obtained on request. Contingency #77 intentionally trips the Project generation. Contingency # Pre Post!N-0_FLAT_RUN Flat sw has-jjb-slo 3 sw has-ngi-slo 4 sw has-pnw-slo 5 sw jjb-kyr-slo 6 sw kyr-brn-slo 7 sw pvd-rud-slo-ts 8 sw pvd-wwg-1-slo-ts 9 sw pvd-wwg-2-slo-ts 10 sw jjb-gil_1 12 sw jjb-gil-2 13 sw gbd-pan-5c-slo 14 sw rud-pvl_5c_slo 16 sw buk-lib-wsps-5c-slo 17 sw19-rud_500_230_1 19 sw20-rud_500_230_2 20 sw21-rud_500_230_3 21 sw22-rud_500_230_4 22 sw23-gil_500_230_1 23 sw24-kyr_500_230_6 24 sw25-kyr_500_230_7 25 sw27-glb_230_069_1 27 sw28-glb_230_069_2 28 sw30-buk_230_069_1 30 sw31-buk_230_069_2 31 sw32-69-gil-thay-slo 32 sw33-69-thay-why-slo 33 sw34-69-gil-cotn-slo 34a sw34-69-cotn-gillespi-slo 34b sw35-69-gillespi-buck-slo 35 sw36-69-pvngpump-baseline-slo 36 sw37-69-buckeye-watsonw-slo 37 sw39-69-gillwest-pvngpump-slo 39 sw40-69-pvngpump-winter-slo 40 sw41-69-saddlemt-buckeye-slo 41 sw43-69-gil-bun-slo 42 sw44a-69-bunyan-cntyline-slo 43 sw45a-69-cntyline-horn-slo 44 sw46a-69-cntyline-saddlemt-slo 46 sw has-jjb-pnw-dlo 63 sw64-gil-jjb_500_1-2_wsps 64 Gen trip at Detroit-stable sw74-69-aztec-q084-slo 74 sw76-69-cntyline-q085-slo 76 sw77-69-cotn-q086-slo 77 sw78-69-cotn-q087-slo 78 Page 18

19 Page 19

20 Page 20

21 Page 21

22 Page 22

23 Page 23

24 Page 24

25 Page 25

26 Page 26

27 Page 27

28 Page 28

29 Page 29

30 Page 30

31 Page 31

32 Page 32

33 Page 33

34 Page 34

35 Page 35

36 Page 36

37 Page 37

38 Page 38

39 Appendix D Construction Schedule Details Page 39

40 Page 40

41 Appendix E Cotton Center Substation One-Line Diagram Page 41

42 Page 42