Feasibility Study for the Duke Energy Florida Suwannee River Plant 214 MW Net Summer / 232 MW Net Winter 230 kv Combustion Turbine December 2013

Transcription

1 Feasibility Study for the Duke Energy Florida Suwannee River Plant 214 MW Net Summer / 232 MW Net Winter 230 kv Combustion Turbine December 2013 Jeffrey Van Dyke Michael Alexander, P.E.

2 This document and any attachments hereto ( document ) is made available by Duke Energy Company upon and subject to the express understanding that: (a) neither Duke Energy Company 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) Duke Energy Company, 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.

3 Table of Contents Generation Description 1 Interconnection Points Evaluated 1 Criteria for Determining Transmission Impact 2 Models 2 Analyses Performed 3 Screening Criteria 3 Study Results 4 Appendix A, Summary of Thermal Analysis Results 5 Appendix B, Summary of Short Circuit Analysis Results 9

4 Suwannee River 230 kv Combustion Turbine Feasibility Study Generation Description Combustion turbine with a 214 MW summer net output (232 MW winter net output) Commercial operation date: June 1, 2016 Interconnection Points Evaluated Point of interconnection requested for study by interconnection customer: Connection to Duke Energy Florida s (DEF) existing Suwannee River 230 kv Substation. Alternative point of interconnection considered by DEF: No other options were considered reasonable or necessary. 1

5 Criteria for Determining Transmission Impact DEF s criteria for identifying transmission facilities impacted by the interconnection of new generation facilities are as follows: Thermal Impact System-intact loading over 100% Rate A. Post-contingency loading over 100% Rate B. Minimum loading increase from Base Case to Interconnection Case of 3%. Voltage Impact System-intact bus voltages lower than 0.95 p.u. or higher than 1.05 p.u. Post-contingency bus voltages lower than 0.90 p.u. or higher than 1.05 p.u. Minimum voltage change from Base Case to Interconnection Case of 0.02 p.u. Short-circuit Impact Three-phase and single line-to-ground fault current over 100% breaker fault duty capability. Minimum fault current increase from Base Case to Interconnection Case of 3%. Model Development Power Flow Models Power flow models were built using the Siemens PSS/E power system simulation program (PSS/E) and were based on the FRCC 2013 series (Revision 1, August 2013) cases, which were the most recent models available at the time of the study. The model seasons studied for power flow impacts were 2016 summer and 2016/17 winter. These FRCC models were updated with relevant new information from the study area, including updated thermal ratings and the dispatch of Crystal River Units 1&2. After these adjustments, FRCC Block & Priority Economic Dispatch was used to reallocate generation within Duke Energy Florida. Finally, an erroneous MVAR load model at PCS/Occidental was corrected, a capacitor bank at Jasper was removed, and several upcoming transmission improvement projects in the area were included. In addition to developing standard 2,400 MW FRCC import cases, high-import sensitivity cases were created assuming a 3,700 MW generation import from the Southern Company. A further sensitivity was created from these cases with the Suwannee Plant steam units offline and at maximum dispatch. These combinations resulted in the creation of four summer Base cases, four winter Base cases, four summer Study cases, and four winter Study cases. Short Circuit Models Short circuit models were built using the PSS/E power system simulation program and were based on the FRCC 2012 series (Revision 1b, December 2012) short circuit cases, which were the most recent models available at the time of the study. The model year studied for short circuit impacts was Generation Interconnection Queue Considerations A proposed new Suwannee River 115 kv combustion turbine was included in both the base and the study cases, as it is a prior queued resource. The DEF Generation Interconnection Queue was reviewed and two prior queued generator interconnection requests (2018 in-service dates) were identified in the relevant study area that will need to be considered in future studies. Transmission Service Request Priority List Considerations A review of transmission service requests in the FRCC coordinated priority list was performed and no relevant transmission service requests were identified in the study area that were not already built into the FRCC cases. 2

6 Analyses Performed Power flow analyses of base case and Suwannee River 230 kv CT cases were performed using PowerGEM TARA software (TARA) to determine the impact of interconnecting the queued generation to the transmission system in the Suwannee River Plant area. The base cases and the 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 single element transmission contingencies (69 kv and above) were analyzed and all branch flows and bus voltages were monitored (69 kv and above) in the FRCC region. The FRCC reliability region consists of peninsular Florida east of the Apalachicola River. The State of Georgia (to the north) and the panhandle area of Florida west of the Apalachicola River in the State of Florida are within the SERC reliability region. PSS/E short circuit analyses were performed using PSS/E activity ASCC. Three phase and single lineto-ground faults were applied up to three breakered buses away from the DEF Suwannee River 230 kv substation in both the base case and the study case to measure short circuit impacts. Fault analysis was performed with all nearby generation in service. Screening Criteria The following criteria were used for screening TARA power flow thermal results. GSU transformers were excluded from consideration. Transmission system elements operated at less than 69 kv nominal voltage were excluded. System-intact overloads greater than 100 percent of rate A were reported Post-contingency overloads greater than 80 percent of rate B were reported Post-contingency loadings with changes of at least 5 MW were reported The following criteria were used for screening TARA power flow voltage results. Transmission system buses operated at less than 69 kv nominal voltage were excluded. System-intact bus voltages outside the range p.u were reported Post-contingency bus voltages outside the range p.u were reported Post-contingency bus voltages with changes of at least p.u. were reported. The following screening criteria were used for screening the PSS/E short circuit results. All results within three breakered buses of the proposed interconnection point were examined. 3

7 Study Results Thermal: System impacts identified for which there is an existing DEF project to address them: Alachua Tap to Alachua 69 kv line (2.3 miles) Alachua to GE Alachua 69 kv line (4.4 miles) Jasper to Branford Tap 115 kv line (35 miles) Jasper to Croft Tap 115 kv line (28.21 miles) Jasper to Burnham Tap 115 kv line (13.16 miles) System impacts identified and assigned to prior-queued generation: Suwannee River 230 kv to Suwannee Plant 115 kv line (0.90 miles) Note: If the prior-queued generation drops out of the queue, the project will be assigned to this proposed Suwannee River 230 kv generator System impacts identified by the addition of this queued resource: Suwannee Peakers to Suwannee River 230 kv line (0.65 miles) Crystal River N Tap to Crystal River East 115 kv line (3.7 miles) Crystal River South to Villa Terrace Tap 115 kv line (0.04 miles) Crystal River to Crystal River East 230 kv line (5.6 miles) Crystal River to Holder Ckt kv line (17 miles) Crystal River East 230/115 kv transformer Suwannee River 230 kv substation breaker upgrades (six new 230 kv breakers) Suwannee River 230 kv substation - Miscellaneous Limiting Element Upgrades Additional system impacts with the Suwannee River steam generation online: Suwannee River 230 kv to Fort White 230 kv line (38 miles) Suwannee to Scott Tap 115 kv line (11 miles) Scott Tap to Fort White 115 kv line (28 miles) GE Alachua to Hull Road 69 kv line (17 miles) 4

8 The feasibility analysis revealed that the interconnection would require a capacity upgrade of the existing DEF 230 kv line from Suwannee Peakers to Suwannee River (0.65 miles). The need for this upgrade is justified by an overload with the new proposed facilities in service. The existing line conductor is sufficient, however, there are substation upgrades and protective relaying that need to be addressed. A C5 loss of the Crystal River to Lecanto 230 kv and Crystal River East to Brookridge 230 kv lines caused a Rate C overload on the 3.7-mile DEF 115 kv line from Crystal River N Tap to Crystal River East. The line conductor is sufficient, however, several substation upgrades and a new 115 kv breaker are required. A C5 loss of the Lecanto to Brookridge 230 kv and Crystal River East to Brookridge 230 kv lines caused a Rate C overload on the 0.04-mile DEF 115 kv line from Crystal River South to Villa Terrace Tap. The existing line conductor is sufficient, however, several substation upgrades are required. A C5 loss of the Crystal River to Holder 230 kv (circuit 1) and Crystal River to Holder 230 kv (circuit 2) caused a Rate B overload on the 5.6-mile DEF 230 kv line from Crystal River to Crystal River East. The existing line conductor is sufficient, however, a limiting wave trap must be replaced. A C5 loss of the Crystal River to Lecanto 230kV and Crystal River to Crystal Rivet East 230 kv lines caused a Rate B overload on the 17-mile DEF 230 kv line from Crystal River to Holder (circuit 1). The existing line conductor is sufficient, however, a limiting wave trap must be replaced. A C5 loss of Crystal River to Lecanto 230 kv and Crystal River East to Brookridge 230 kv lines caused a Rate B overload on the DEF 230/115 kv transformer at Crystal River East. The existing transformer is sufficient, however, several substation upgrades are required. In addition to these impacts, amp analysis of the Suwannee 230 kv yard demonstrated that much of the 230 kv equipment would need to be upgraded to 3000 amps, including buswork and the six existing 230 kv breakers. With the Suwannee River steam generation online, breaker failures at Florida Power & Light s Duval 500 kv substation caused Rate C overloads on the 38-mile DEF 230 kv line from Suwannee River to Fort White. The existing line conductor is sufficient, however, several substation upgrades are required. Also, with the Suwannee River steam generation online, several C2 breaker failure scenarios involving loss of the Suwannee River 230 kv to Fort White 230 kv line resulted in a potential Rate B impact to the 11-mile DEF 115 kv line from Suwannee to Scott Tap and the 28-mile DEF 115 kv line from Ft White to Scott Tap. These impacts require a full line rebuild for both of these line segments to a higher capacity. Finally, with the Suwannee River steam generation online, C2 breaker failures at Archer substation result in Rate C overloads on the 17-mile DEF 69 kv line from GE Alachua to Hull Road. These impacts require a full line rebuild for this line segment to a higher capacity. See Appendix A for a summary of thermal analysis results. 5

9 Voltage: No adverse voltage impacts were noted within DEF as a result of the interconnection of the Suwannee River 230 kv combustion turbine. However, numerous third party voltage impacts were observed which could have potential impacts on the Florida-Southern Transfer Import Capability. These will be investigated in a future coordinated study. Please see the electronic Appendices for a summary of voltage analysis results. Short Circuit: Short circuit analyses revealed that the interconnection of the Suwannee River 230 kv CT facilities would cause impacts greater than 3% at the Suwannee River Plant, Fort White, Jasper, Madison, and Perry substations. While these substations will be analyzed in greater detail in a future system impact study, the magnitude of the fault current revealed in the feasibility analysis does not appear to exceed the fault capability of existing components at these substations. See Appendix B for a summary of short circuit analysis results. Third Party Impacts: Numerous third-party impacts appeared in the thermal results. These will be investigated in a future coordinated study. See Appendix A for a summary of third party thermal results. Costs: Based on this Feasibility Study, the cost to interconnect the Suwannee River 230 kv CT at DEF s Suwannee River 230 kv substation is estimated to be approximately $77.2 Million. With the Suwannee River steam generation offline, this estimate drops to $10.9 million. Please note this estimate does not include the cost of possible third party impacts, which will be quantified in a future coordinated study. 6

10 Appendix A Summary of Thermal Analysis Results *Yellow denotes an impact of a Rate B violation or a 3% aggravation of an existing violation. Red denotes a Rate C violation. Impacts on Suwannee to Suwannee Plant 115kV 7

11 Impacts on Suwannee Peakers to Suwannee River 230kV line *Not all results are shown. See electronic results for remainder. 8

12 All Other DEF Impacts, Category B 9

13 All Other DEF Impacts, Category C 10

14 Third Party Impacts, Category B 11

15 Third Party Impacts, Category C 12

16 Appendix B Summary of Short Circuit Analysis Results Bus Number Bus Name 384 COLUMBIA FT WHITE JASPER MADISON SUWANNEE PLT SUWANNEE RV OCC SWIFTCK1 SUWAN PLT B CRAWFORD VLLE Base 230CT Delta Capacity Duty Bus kv Fault Type (Amps) (Amps) (%) (Amps) (%) FT WHITE N NEWBERRY PERRY SUWANNEE PKR SUWANNEE RV ST MARKS GINNIE TWINLAKS PINEGRVE N TIFTON Phase to Ground % Single Line to Ground % Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % Single Line to Ground % Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % Single Line to Ground % Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % Single Line to Ground % Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % Single Line to Ground % Phase to Ground % % Single Line to Ground % % 3-Phase to Ground % Single Line to Ground %