Feasibility Study Report

Transcription

1 Report For: [Company Name] ( Customer ) Queue #: Service Location: Forsyth County, NC Total Output: 875 MW Commercial Operation Date: 6/1/2017 Prepared by: Orvane Piper, Duke Energy Carolinas Feasibility Study Report Redacted ( ).docx

2 Table of Contents 1.0 Introduction Study Assumptions and Methodology Thermal Study Results NRIS Evaluation ERIS Evaluation Fault Duty Study Results Reactive Capability Study Results... 5 Page 2 of 5

3 1.0 Introduction Following are the results of the Generation Feasibility Study for the installation of 875 MW of generating capacity in Forsyth County, NC. This site is located near Beckerdite Tie and has an estimated Commercial Operation Date of 6/1/ Study Assumptions and Methodology The power flow cases used in the study were developed from the Duke internal year 2017 summer peak case. The results of Duke s annual screening were used as a baseline to identify the impact of the new generation. All cases were modified to include 875 MW of additional generation at the Customer s facility. To determine the thermal impact on Duke s transmission system, the new generation modeled with a 230 kv connection at Beckerdite Tie. The economic generation dispatch was also changed by adding the new generation and forcing it on prior to the dispatch of the remaining Duke Balancing Authority Area units. The study cases were re-dispatched, solved and saved for use. The NRIS thermal study uses the results of Duke Energy Power Delivery s annual internal screening as a baseline to determine the impact of new generation. The annual internal screening identifies violations of the Duke Energy Power Transmission System Planning Guidelines and this information is used to develop the transmission asset expansion plan. The annual screening provides branch loading for postulated transmission line or transformer contingencies under various generation dispatches. The thermal study results following the inclusion of the new generation were obtained by the same methods, and are therefore comparable to the annual screening. The results are compared to identify significant impacts to the Duke Energy transmission system. Fault studies are performed by modeling the new generator and previously queued generation ahead of the new generator in the interconnection queue. Any significant changes in fault duty resulting from the new generator s installation are identified. Various faults are placed on the system and their impact versus equipment rating is evaluated. Reactive Capability is evaluated by modeling a facility s generators and step-up transformers (GSUs) at various taps and system voltage conditions. The reactive capability of the facility can be affected by many factors including generator capability limits, excitation limits, and bus voltage limits. The evaluation determines whether sufficient reactive support will be available at the Connection Point. Page 3 of 5

4 3.0 Thermal Study Results 3.1 NRIS Evaluation The following network upgrades were identified as being attributable to the studied generating facility: Facility Name/Upgrade Existing Size/Type Proposed Size/Type Mileage Estimated Cost Lead Time (months) 1. Interconnection cost N/A N/A N/A TBD TBD 2. Upgrade Linden St 100 kv Lines (Beckerdite-Linden St) 3. Upgrade Silas 100 kv Lines (Mocksville-Advance Retail) 477 ACSR B477 ACSR 15.7 $20 M 36 2/0 Cu 477 ACSR 9.26 $12.5 M Add Transformer At Buck Tie N/A 448 MVA N/A $5.9 M Replace Transformer At Beckerdite Tie CUSTOMER TOTAL COST ESTIMATE 200 MVA 448 MVA N/A $3.9 M 24 $42.3 M 1 36 The listed upgrades are also required for all scenarios including higher queued generation. 3.2 ERIS Evaluation The Customer did not request evaluation of ERIS service. 4.0 Fault Duty Study Results The following breakers will need to be replaced: 1. At Beckerdite Tie the following twelve 100 kv breakers: Beckerdite Retail HT, SVC Red & Yellow, Bank 1 LT Red & Yellow, Bank 2 LT Red & Yellow, Bank 3 LT Red & Yellow, Bank 4 LT Red & Yellow, capacitor bank 2. At Buck Steam Station the following five 100 kv breakers: Buck Bl, Grants Creek Bl & Wh, Salisbury Bl & Wh 3. At Linden Street the following 100 kv breaker: Randleman Bl 4. At Shattalon Switching Station the following five 100 kv breakers: Bethania Bl & Wh, Shattalon Bl & Wh, Walnut Cove Bl/Wh 5. At Winston Tie the following 100 kv breaker: Salem Wh 1 Interconnection costs are not included in the total estimate at this time. Page 4 of 5

5 Total estimated cost for breaker replacements: $7.5 M The listed breakers are also required for all scenarios including higher queued generation. 5.0 Reactive Capability Study Results With the proposed generating facility, the level of reactive support supplied by the units has been determined to be acceptable at this time. Evaluation of MVAR flow and voltages in the vicinity of Beckerdite Tie indicates adequate reactive support exists in the region. The recommended GSU tap setting is kv. Study completed by: Orvane Piper, Duke Energy Carolinas Reviewed by: Ben Harrison, Duke Energy Carolinas Director, Transmission Planning Carolinas Page 5 of 5