Feasibility Study for the Q MW Solar Project

Transcription

1 Feasibility Study for the Q MW Solar Project August 2018 Bulk Transmission Planning, Florida i

2 This document and any attachments hereto ( document ) is made available by Duke Energy Florida, LLC ( DEF ) upon and subject to the express understanding that: (a) neither DEF nor any of its officers, directors, affiliates, agents, or employees makes any warranty, assurance, guarantee, or representation with respect to the contents of the document or the accuracy or completeness of the information contained or referenced in the document, and (b) DEF, its officers, directors, affiliates, agents, and employees shall not have any liability or responsibility for inaccuracies, errors, or omission in, or any business or policy decisions made by any direct or indirect recipient in reliance on, this document or the information contained or referenced therein; all such liability is expressly disclaimed. ii

3 Table of Contents 1. Executive Summary Point of Interconnection (POI) Model Development Power Flow Models Interface Models Short Circuit Models Generator Interconnection Queue Considerations Transmission Service Request Priority List Considerations Analyses Performed Power flow analyses Short circuit analyses Screening Criteria Study Results Thermal Results Voltage Short Circuit Third-party Impacts Costs... 6 Appendix A - Summary of Thermal Analysis Results... 7 Appendix B - Short Circuit Analysis Results

4 1. Executive Summary The Q195 Interconnection Customer has submitted an Interconnection Request on DEF s system for a Solar PV station, capable of 74.9 MW ac net output. The facility will be located in Suwannee County, Florida connecting to a new breakered terminal at the Suwannee River Plant 115 kv Substation. The Interconnection Customer has requested this generation facility be evaluated for Network Resource Interconnection Service ( NRIS ) plus Energy Resource Interconnection Service ( ERIS ) with a requested Commercial Operating Date ( COD ) of September 1, Cost estimates in this report are based on the facilities that are identified as directly impacted by the generator under study, and do not take into account results that may indicate unrelated existing issues. Additional detailed study may result in changes to scope and cost. The estimates from this Feasibility Study are only Planning estimates (level 5) and may change significantly due to additional information determined from a more detailed System Impact and Facilities Studies to follow. This study included some network upgrades that are associated with prior queued requests. If one or more of the prior-queue requests are modified or withdrawn, Q195 may become responsible for these upgrades, in addition to facilities identified in this report. Q195 was studied as being connected to a new 115 kv terminal at Suwannee River Plant 115 kv substation. This evaluation did not identify any network upgrades to DEF s transmission system to accommodate the full capacity (74.9 MW) of the Q195 Solar PV project. There were additional potential regional impacts that will require further evaluation in the System Impact Study. No potential Third Party thermal impacts were identified. The short circuit analysis revealed some increases in the fault current, but no DEF devices were found to be impacted by this increase. Additional in depth analysis for third party impacts will be performed in a future FRCC Transmission Technical Subcommittee evaluation, following the System Impact Study, if the customer moves to a Facilities Study. The conclusion of this Feasibility Study is that Q195 could be connected via a customer-supplied generator tie line (approximately two miles in length) to a new 115 kv breakered terminal at DEF s Suwannee River Plant 115 kv substation. The estimated cost required for a new breakered terminal at Suwannee River Plant 115 kv substation to accommodate the interconnection of the Q195 Solar PV project is $2,000,000. In addition, the customer would be responsible for the construction, ownership, and maintenance of the generator tie line. 2

5 2. Point of Interconnection (POI) There is only one POI requested for study by interconnection customer: A new 115 kv breakered terminal at existing 115 kv Suwannee River Plant substation. Two mile long 115kV customer-supplied Gen-Tie Figure 1: Diagram of Q195 Interconnection 3. Model Development 3.1. Power Flow Models Power flow models were built using the Siemens PSS/E power system simulation program and were based on the FRCC 2017 series cases, which were the most recent models available at the time of the study. The model year studied for power flow impacts was 2020 winter and 2021 summer Interface Models No interface analyses were performed as part of this evaluation Short Circuit Models Short circuit analysis performed utilized the FRCC 2017 short circuit model (y17_21s- SCRls2_V34.sav). The model year studied for the short circuit analysis was 2021s. Note: Customer did not provide adequate modeling data at the time of the study for the 3 winding transformer indicated on the customer provided one line diagram. Short circuit case models were built using data from a similar sized solar PV s 3 winding transformer Generator Interconnection Queue Considerations Prior queued generation in the FRCC coordinated queue was reviewed. Several prior-queued generator interconnections that are currently undergoing the study process, and directly impact the area of the study project, were identified. In DEF s area: Q144A, Q148, Q180C,Q181, FLS010, Q151, Q152, Q153, Q154, Q155B, Q158, Q159, Q160, Q166, Q169, Q171, Q174, Q182, Q189A, Q190B, Q193, Q194A, Q194B. From FPL: Q193, Q212, Q250, Q259, Q262, Q327. 3

6 Generator Interconnect Studies for prior queued generation interconnection requests in the form of Feasibility and System Impact Studies are currently conducted in accordance with FERC rules and are prioritized by their queue positions to determine the assignment of required interconnection facilities and transmission upgrades to accommodate their requested interconnections. In the instances where these studies are not sufficiently complete, the facilities and upgrades required for these earlier queued requests might not be included in the base cases used in this study. To the extent that one or more of these requests completes, are modified or withdrawn, the results presented in this analysis may no longer be valid and/or may change materially. DEF will advise the customer of any changes associated with the preceding GIS requests that may require a re-study of this GIS request Transmission Service Request Priority List Considerations A review of transmission service requests in the FRCC coordinated priority list was performed, and it was determined that there are no relevant transmission service requests in the study area that were not already built into the FRCC cases. 4. Analyses Performed 4.1. Power flow analyses Power flow analyses of the cases were performed using the PowerGEM TARA software (TARA) to determine the impact of interconnecting the queued generation to the transmission system in the area. The base and interconnection study cases were compared to determine if the interconnection option created thermal overloads or voltage violations or exacerbated existing thermal overloads or voltage violations. All 69 kv and above branch flows and bus voltages in the FRCC region were monitored. The following contingencies were observed in this study: Selected Category P1, P2, P4, P5, and P7 contingencies within the FRCC region as previously defined by FRCC transmission owners. Selection variations include: o All single element contingencies (69 kv and above) in the FRCC region 4.2. Short circuit analyses Short circuit analyses were performed using PSS/E activity ASCC. All local generators were online for the analysis. Activity FLAT was used to set up the network conditions corresponding to classical fault analysis assumptions. Three phase and single line-to-ground faults were applied at all buses within FRCC and were analyzed using a 3% screening criterion. Devices that are installed to interrupt fault current (breakers, circuit switchers, etc.) that are connected to buses identified in the screened results will need to be evaluated to determine whether their fault current interrupting capabilities are exceeded. This evaluation of the impact of increased fault current on DEF devices will be performed during the subsequent Facilities Study and the evaluation of the impact on third party devices will be performed separately during the FRCC process. The final results represent all buses 4

7 within FRCC with a difference between the base case and study case greater than 3%, in addition to the next bus out in the affected area to capture the total impact. 5. Screening Criteria The following criteria were used for screening thermal results: Unrelated GSU transformers were excluded from results. Transmission system elements operated at less than 69 kv nominal voltage were excluded. System-intact overloads must be greater than 100% of rate A. Post-contingency overloads must be greater than 100% of rate A. Post-contingency overloads that are improved by the interconnection were excluded. Post-contingency overloads must have been made worse than the base case by 3% of the affected element s rating or greater. The following criteria were used for screening voltage results: Buses in DEF and SECI were monitored for values outside of the range p.u. FPL 69, 115, 138, and 230 kv buses were monitored for values outside the range p.u. FPL 500 kv buses were monitored for values outside the range p.u. TECO 69 kv buses were monitored for values outside the range p.u. TECO 138 and 230 kv buses were monitored for values outside the range p.u. Turkey Point bus voltage was monitored for values outside the range of 1.01 p.u. and 1.06 p.u. St. Lucie bus voltage was monitored for values outside the range of 1.00 p.u. and 1.06 p.u. All other monitored areas were monitored for values outside of the range 0.95 and1.05 p.u. Generator buses and buses with nominal voltage below 69 kv were excluded from consideration. Absolute change in bus voltage between base case and the interconnection case must have been greater than 0.02 p.u. The following screening criteria were used for screening the ASCC short circuit results: Three phase and single line-to-ground fault current on the DEF system had to exceed the interrupting rating of the breaker. Three phase and single line-to-ground fault current results are provided to third parties close to this area for their acceptance or rejection of the results based on their own breaker rating criteria. The table in Appendix B Short Circuit Analysis Results (below) reflects increases in fault current greater than 3%, in addition to the next bus out to represent the total impact. 5

8 6. Study Results 6.1. Thermal Results The evaluation did not identify any potential network upgrades to DEF s transmission system to accommodate the full capacity (74.9 MW) of the Q195 Solar Project. However, there were some other potential impacts that might be aggravated due to the interconnection of Q195. If further analysis finds that these impacts cause current workable mitigations to no longer be valid, curtailing Q195 output might be necessary. The results for the analysis are shown in Appendix A. Additional analysis will be performed in the future System Impact Study Voltage There were no identified voltage violations that were attributable to the interconnection of the Q195 Solar Project interconnection Short Circuit Short circuit analysis was performed and the results were evaluated against the interrupting capability of potentially impacted devices in DEF s system. No devices were identified that would likely exceed their interrupting capability.. The short circuit results are tabulated in Appendix B Third-party Impacts The thermal analysis did not reveal potential third-party impacted facilities. Short circuit analysis revealed no potential third-party substations with a short-circuit impact greater than 3%. Additional in depth analysis for third-party impact will be performed in a future FRCC Transmission Technical Subcommittee evaluation following the System Impact Study if the customer moves to Facilities Study Costs Required upgrades for basic physical interconnection: Est. Costs New 115 kv breakered terminal at existing Suwannee River Plant substation $2,000,000 Total Estimated Cost: $2,000,000 These estimates are preliminary planning estimates, and details specific to this project discovered in the System Impact Study and Facilities (design engineering) Study phases may significantly increase or decrease these estimates. The issues of ISDs and possible project costs for upgrades identified (Appendix A) in prior queued studies will be addressed in the System Impact Study to follow where we will more thoroughly determine the impact of prior queued requests. 6

9 Appendix A - Summary of Thermal Analysis Results WINTER Winter 2020 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S1 Study S1 Delta 469 SANFORDI DEBARY P2-3:FPL-SN P Note: Base S1: Base + IA + Network Updates (01_y17_20wRP1_Pk_Base_S1). Study_S1: Base + IA + Network Updates + Q195 (02_y17_20wRP1_Pk_Study_S1). Winter 2020 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S2 Study S2 Delta N/A N/A N/A N/A N/A Note: Base + IA + Network Updates + Previous Queues (03_y17_20wRP1_Pk_Base_S2). Study S2: Base + IA + Network Updates + Previous Queues (04_y17_20wRP1_Pk_Study_S2). Results potentially impacting 3rd parties to be resolved under the FRCC process. Winter 2020 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S1 Study S1 Delta N/A N/A N/A N/A N/A Note: Base S1: Base + IA + Network Updates (01_y17_20wRP1_Pk_Base_S1). Study_S1: Base + IA + Network Updates + Q195 (02_y17_20wRP1_Pk_Study_S1). Winter 2020 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S2 Study S2 Delta N/A N/A N/A N/A N/A Note: Base + IA + Network Updates + Previous Queues (03_y17_20wRP1_Pk_Base_S2). Study S2: Base + IA + Network Updates + Previous Queues (04_y17_20wRP1_Pk_Study_S2). SUMMER Summer 2021 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S1 Study S1 Delta N/A N/A N/A N/A N/A Note: Base S1: Base + IA + Network Updates (05_y17_21sRP1_Pk_Base_S1). Study_S1: Base + IA + Network Updates + Q195 (06_y17_21sRP1_Pk_Study_S1). Summer 2021 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S2 Study S2 Delta 469 SANFORDI ALTAMONTE P2-3:DEF_NLGW_ SANFORDI ALTAMONTE P4:2-DEF_NLGW_ SANFORDI ALTAMONTE P7:DEF-MRTL-WKVA SANFORDI ALTAMONTE P7:FPL _ _ HOMOSASSA2TP TWIN CO RNCH P7:DEF-LECA-BKRG HOMOSASSA2TP VILLA TER TP P7:DEF-LECA-BKRG WESLEY CH TP CABBAGE_HILL P1-2:66055_ WESLEY CH TP CABBAGE_HILL T-P2-1:66055_69( ) Note: Base + IA + Network Updates + Previous Queues (07_y17_21sRP1_Pk_Base_S2). Study S2: Base + IA + Network Updates + Previous Queues (08_y17_21sRP1_Pk_Study_S2). Results potentially impacting 3rd parties to be resolved under the FRCC process. Summer 2021 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S1 Study S1 Delta 7

10 N/A N/A N/A N/A N/A Note: Base S1: Base + IA + Network Updates (05_y17_21sRP1_Pk_Base_S1). Study_S1: Base + IA + Network Updates + Q195 (06_y17_21sRP1_Pk_Study_S1). Summer 2021 Results Meeting Impact Criteria - % Loading Monitored Facility Contingency Name Base S2 Study S2 Delta N/A N/A N/A N/A N/A Note: Base + IA + Network Updates + Previous Queues (07_y17_21sRP1_Pk_Base_S2). Study S2: Base + IA + Network Updates + Previous Queues (08_y17_21sRP1_Pk_Study_S2). 8

11 Appendix B - Short Circuit Analysis Results PSS E ASCC SHORT CIRCUIT CURRENTS 1.0 pu) Base Case Study Case Short Circuit Bus # Bus Name kv Area 3φ (I1) SLG (3I0) 3φ (I1) SLG (3I0) % 3φ % SLG 3133 SUW TRANSM 115 DEF % 1.90% 3157 SUWAN DISTR 115 DEF % 1.88% 3183 SUW DSTR TP 115 DEF % 1.75% 3132 SUWAN PLT A 115 DEF % 1.70% 3158 SUWAN PLT B 115 DEF % 1.70% 3130 SCOTT TP 115 DEF % 1.68% 6984 SCOTT 115 DEF % 1.68% Q144A HS 115 DEF % 1.51% Base Case: "y17_21s-scrls2_v34preevaqall.sav with prior queues and all FRCC generation in-service. Study Case: Base case plus Q195 PV generator. Third Party Impacts PSS E ASCC SHORT CIRCUIT CURRENTS 1.0 pu) Isc Bus # Bus Name Breakered kv Area 3φ (I1) Base Case Study Case Short Circuit SLG (3I0) 3φ (I1) SLG (3I0) % 3φ % SLG Base Case: "y17_21s-scrls2_v34preevaqall.sav with prior queues and all FRCC generation in-service. Study Case: Base case plus Q195 PV generator. 9