SCE&G Transmission Planning Summit - … Hydro 10MW Coit Turbines 32MW ... transformer connected to the Transmission System: ... SCE&G Transmission Planning Summit

““Power For LivingPower For Living””SCE&G Transmission PlanningSCE&G Transmission Planning

SCE&G Transmission Planning SummitSCE&G Transmission Planning Summit

SCE&G Transmission Planning

Summit

February 20, 2007



Logistical Information

• Sign-In• Exits• Restrooms• Lunch• Meeting Materials



Order 890

• Reforms Order 888 (Open Access Order)• Approved by the FERC February 15, 2007• More open and transparent Local and Regional

Transmission Planning Process– Open to all transmission users

• Wholesale customers• Generators• Marketers



Meeting Purpose

Increase understanding of:• SCE&G Transmission System Facts• SCE&G Transmission Planning Process

– Internal Planning– Regional Planning

• SCE&G Transmission System capabilities and limitations

• SCE&G Transmission Expansion Plan


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitAgendaWelcome and Opening RemarksTransmission Planning Objectives and System FactsPower System Modeling

Load ForecastingModel Development

Internal Planning ProcessPlanning CriteriaBreakTransmission Expansion Drivers

Regional Planning ProcessJoint Study Activities

LunchSCE&G Transmission Expansion PlanClosing Comments



Transmission Planning Objectives andSystem Facts



Transmission Planning Objectives

Identify transmission expansion and modifications to safely, reliably and economically:– transmit electric power from SCE&G generators to SCE&G

customers– transmit electric power from off-system purchases to

SCE&G customers– provide Interconnection Service to all generators– provide Transmission Service to marketers and generators– maintain synchronism with the Eastern Interconnection



SCE&G Transmission System FactsLinesVoltages Miles230 kV 1136115 kV 168346 kV (sub-transmission) 68833 kV (sub-transmission) 70

Total 3577



SCE&G Transmission System FactsSubstationsType #Generation (Step-up) 20Transmission 43Distribution 201Single Customer 181Total 445


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitSCE&G Transmission System Facts

Transmission Interties 230kV 115kV

Duke 2 2Progress Energy Carolinas 2 1Santee Cooper 7 5Southern (Georgia Power) 1 1SEPA 0 1

12 10

Total Interties 22



Transmission IntertiesDuke

SEPA

Southern

Progress Energy

Santee Cooper


Stevens Creek 18MW

Urquhart 598MW

UrquhartTurbines 103MW

BurtonTurbines

30MW Hardeeville

Turbine 15MW

Jasper875MW

HagoodICT

96MW

Williams615MW

WilliamsTurbines

56MW

Canadys 406MW

Canadys Turbines

15MW

Columbia Hydro 10MW

Coit Turbines

32MW

Summer966MW

(644MW)

Saluda Hydro206MW

McMeekin250MW

Parr Hydro 14MW

Fairfield576MW

ParrTurbine 64MW

Faber PlaceTurbines

9MW

Cope420MW

Columbia Energy Center 620MW

Westvaco90MW


Connected Generation(6682 MW)



SCE&G Generation Queue(next 10 Years)

• 2 Nuclear Units• 1 Coal Unit• 9 Combustion Turbines

Total – 4257 MW



Power System Modeling

Load Forecasting


Dispersed Substation Load Forecast contains for each transformer connected to the Transmission System:

• SCE&G is normally summer peaking• SCE&G creates a summer and winter forecast• Peak Transformer Loads for Prior Ten Years• Current Year Peak Transformer Load• Projected Load Increases for Upcoming 10 Years



Load Information Gathering

• Contact the Metering Department after the summer peak –Normally mid September

• Request 15 Minute metered readings for each transformer• Receive data and tabulate into prior 10 year forecast• Data added includes peak MW and MVAR• Spreadsheet calculates Peak MVA



Lexington Westside 115-23kv Transformer #1 - Sub #281 - 37.3MVA

Historical Summer Load (MVA) Projected Load Increase (MVA)

1996 22.0 2007 1.01997 24.1 2008 1.01998 24.6 2009 0.51999 27.8 2010 0.52000 22.6 2011 0.52001 29.0 2012 0.52002 31.3 2013 0.52003 30.0 2014 0.52004 33.4 2015 0.52005 37.0 2016 0.52006 37.1

2007 Calculated Peak 38.1MVA2007 Percent Loaded 102%



Lexington Westside 115/23kV #1

0

5

10

15

20

25

30

35

40

45

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

2016

Year

Load

(MVA

)

Load (MVA)Capacity



Initial Review

• Compare the most recent peak load for consistency with prior year’s peaks

• Expect plus or minus 5%-10% of prior year• Consider weather conditions and local area growth• For variations above 10% check load against monthly

SCADA readings taken by Distribution• Adjust loads if load switching occurred• Project load increases on each transformer year by year for

the upcoming 10 years



Review By SCE&G Distribution Group

• Forward electronic copy to Local Managers and Distribution Planning for comments

• Request review for accuracy of the peak load• Request review of anticipated step load additions in MW

for the next 10 years for each transformer• Receive comments, discuss further as necessary with

Distribution• Make adjustments to the 10 year forecast



Information from Industrial Customers

• Contact Manager of the Large Industrial Group• Request customers be contacted for known load

additions/reductions over the next 10 years• Incorporate into the 10 year Forecast



Information from Industrial Development

• Contact Manager of Industrial Development• Identify all potential new Industrial Customers and expected

10 year load forecast• Incorporate appropriate customer loads into the 10 year

Forecast



Information from Wholesale Customers

• Contact Manager of Transmission Services• Request annual 10 year forecast for Summer and Winter

for each Wholesale Customer• Incorporate Wholesale Customer loads into the 10 year

Forecast



Internal Review

• Meet with other Transmission Planners• Review Entire Document for Consistency• Receive Corporate 10 year forecast and align to agree –

Wholesale and Industrial Customer Load Projections are not adjusted

• Archive• Provide results for internal Model Development




Power System Modeling

Model Development



Model Components• Generators • Capacitors• Transmission Lines • Reactors• Transformers • Breakers• Load • FACTS Devices• Firm Power Transfers • etc.


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitTypes of Models and their Application• Power Flow Models

– Predict Future Transmission Expansion– Analyze thermal loading and voltages– Test Transfer Capability

• Stability Models– Criteria Testing– Generator Interconnection– FSAR


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitTypes of Models and their Application• Short Circuit Models

– Calculate Available Fault Current– Breaker Evaluation, Equipment Sizing and Motor Start

Analysis– Grounding Design

• Loss Factor Models– Determine SCE&G System Losses


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitModel Development - Internal• Dispersed substation load forecast

– Summer/Winter Peak, Off-Peak and Seasonal Load Levels• Existing generation

– Input from Generation Maintenance Schedule• Generation additions

– Input from Generation Expansion Plan• Transmission additions

– Input from Planners and Engineering• Firm Transmission Service

– Input from OASIS, Coordinate with Neighbor



Model Development - External• SERC

– SERC Databank Update• SCE&G • Southern Company• Duke Power • GTC• Progress Energy – Car. • MEAG• Santee Cooper • TVA• Virginia Power • Entergy• Ameren • Others

– Develop Southeastern models for the next ten years



SERC Region


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitModel Development - External• Eastern Interconnection

– NERC• SERC and five other NERC Regions• Includes transmission systems from Florida to North Dakota and from

Eastern New Mexico (parts of Texas) to Maine• Includes transmission systems in Canada from Nova Scotia to

Saskatchewan– Develop Eastern Interconnection models for the next ten years– All participants receive a copy of the final models

These Eastern Interconnection models are the models used to planthe SCE&G Transmission System



NERC



SCE&G Internal Planning Process

Planning Criteria


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitPlanning Standards• North American Electric Reliability Council

(NERC/ERO)– Originally developed in 1996– Ongoing revisions since– Currently being reviewed and revised by FERC– EPAct 2005 made these standards the law

• Non-compliance penalties up to $1,000,000 per day

• SCE&G Internal Planning Criteria– Developed in 1970


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitCriteria TestingThese criteria can be briefly summarized as:

• The SCE&G Transmission System is planned such that if a transmission, generation or load event suddenly occurs, the response of the system will be within acceptable limits and stability is maintained.

• In case a sudden event occurs:– system voltages must be maintained– all transmission facility loadings are less than the applicable rating– system stability and synchronism are maintained



Criteria Testing• A sample of events simulated are:

– Loss of any generating unit– Loss of any transmission line– Loss of any transmission transformer– Loss of any electrical bus section and connected facilities– Loss of entire generating capacity in any one plant– Loss of all circuits on a common transmission structure– Loss of any generator, line or transformer, followed by system

adjustments, and then the loss of another generator, line or transformer

– etc.




SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitPlanning Cycle

Year 20nnBase CaseYear 20nnBase Case

CriteriaTestingCriteriaTesting

AlternativeDevelopmentAlternative

DevelopmentCost/Benefit

AnalysisCost/Benefit

Analysis

SolutionSelectionSolutionSelection

ManagementApproval

ManagementApproval

TransmissionExpansion

Plan for 20nn

TransmissionExpansion

Plan for 20nnYear + 1Year + 1



Break



SCE&G Internal Planning Process

Transmission Expansion Drivers



Transmission Expansion Drivers• Develop 10 year transmission expansion plan based on:

– Criteria testing– Distribution needs– Industrial Customer needs– Network/Wholesale Customer needs– Generator Interconnection needs– Firm Transmission Service needs– Actual system performance (poor performance)


Transmission Planning ProcessTransmission Planning ProcessSCE&G Internal PlanningSCE&G Internal Planning



Regional Planning Process


Regional Planning - Regional Reliability Agreements

• The Southern Companies and Entergy 1967• Tennessee Valley Authority (TVA) and Southern 1968• TVA and Entergy 1968• Virginia-Carolinas (VACAR) 1970• VACAR and Southern 1971• TVA and Carolina Power & Light (CP&L) 1971• Southern and Florida Coordinating Group (FCG) 1980• TVA and Oglethorpe Power Corporation (OPC) 1994• TVA & Municipal Electric Authority of Georgia 2000



Regional Planning - Regional Reliability Agreements

• The purpose of the Reliability Agreements is to augment further the reliability of each party’s bulk power system

• The Reliability Agreements require, among other things, that theparties– exchange information within the Region– conduct joint studies and investigations– coordinate voltages and reactive interchange– make necessary recommendations designed to increase reliability of the

interconnected bulk power system



• Focus on the interaction between systems and the impact of that interaction on the reliability of serving load

• Focus on the ability to transfer power between systems for reliability and economic purposes




Planning Arenas

• Individual System Planning• Subregional System Planning

– Facilitated Planning– Coordinated Planning– Joint Planning

• Regional System Planning– Facilitated Planning– Coordinated Planning– Joint Planning

VACAR

ProgressCarolina

DominionVP

DukeSCE&G

SCPSA

ENTERGY

GATEWAY

TVA SOUTHERN

SERC




VACAR (Virginia and Carolinas)SCE&G Santee Cooper Progress Energy CarolinasDuke Virginia Power Fayetteville, NCNCEMC SEPA Yadkin, Inc

VACAR Studies– Future year planning studies– Criteria testing– Power Transfer Capability



VACAR Subregion

SEPA

SCPSA

DUKEPECw

YADKIN

VP

PECe

SCE&G

NCEMC




SERC - Long-term Studies– Future year planning studies– Criteria testing– Power Transfer Capability

SERC - Near-term Studies– Seasonal reliability studies (summer and winter)– Used by System Operators to predict system performance and

system constraints for the upcoming season



SERC Region




SERC Inter-regional Studies– SERC – Reliability First– SERC – MRO– SERC – SPP– SERC – Florida



NERC



Transfer Capabilities and Limits


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitPower Transfer CapabilitiesOASIS Support Studies

– Transfer Capability Studies– Commercially viable transfer values– Used to populate the SCE&G OASIS– SCE&G Transfer Capabilities Calculated (Import and Export

values):• Duke• Progress Energy Carolinas• Santee Cooper• Southern Company


ATC Calculations – Imports and Exports

Definitions and Formulas:

Total Transfer Capability (TTC) = First Contingency Incremental Transfer Capability (FCITC)

Transmission Reliability Margin (TRM) = Margin to ensure system is operated reliably

Capacity Benefit Margin (CBM) = Margin to ensure connected LSEs have access to external generation resources

Available Transfer Capability (ATC) = TTC – TRM – CBM – Committed Uses




TTC

Non Firm ATC

Firm ATC

CBM

TRM

CommittedUses

Available Transfer Capability (ATC) = TTC – TRM – CBM – Committed Uses



2007 Summer Firm ATC - Imports

Transfer Firm ATC (MW)

PEC to SCE&G 523

Duke to SCE&G 542

SCPSA to SCE&G 381

Southern to SCE&G 1203



2007 Summer Firm ATC - Exports

Transfer Firm ATC (MW)

SCE&G to PEC 694

SCE&G to Duke 860

SCE&G to SCPSA 600

SCE&G to Southern 970



Lunch



SCE&G Transmission Expansion Plan



1

234

56

78

9

10

1112

13

14

15

Major Transmission Projects1) Lake Murray 230/115 Sub

2) Hopkins 230/115 Sub3) Landfill Switching

Sta.4) Denny Terrace –

Lyles 230kV Line5) Pepperhill 230/115

Sub and Lines6) Church Creek –

Savage Road 115kV Double Circuit

7) Accabee-Charlotte St. 115kV Double Circuit and Foldin at Hagood

8) Mt. Pleasant Area Improvements

9) Canady – Church Creek 230kV Double Circuit and Fold-in at Pepperhill

10) Barnwell-SRS 115kV Line

11) Urquhart – Belvedere 115kV Double Circuit

12) Graniteville 230/115kV Transformer Upgrade

13) Yemassee 230/115kV Transformer Upgrade

14) Yemassee – Burton 115kV Double Circuit

15) Ritter 230/115kV Sub


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitColumbia Area

• Load: 1900 MW• Generation: 3516 MW

– SCE&G: 2582 MW– Santee Cooper: 322 MW– IPP: 612 MW



Columbia Area Major Transmission Projects

• Lake Murray 230/115 kV Transmission Substation• Hopkins 230/115 kV Transmission Substation • Landfill 115 kV Switching Station and Capacitor Bank• Denny Terrace-Pineland 230 kV Line and add Pineland 230/115 kV #2


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitLake Murray 230/115 kV Transmission Substation and Lines

• Problem:– Contingency:

• Outage of the Denny Terrace 230/115kV #1 and the Lyles 230/115kV #1 transformers

• 16 other events cause problems– Result:

• Overloaded transformers and 115kV transmission lines in the Columbia and Lake Murray area

• Other overloaded facilities and low voltages


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitLake Murray 230/115 kV Transmission Substation and Lines

• Solution:– Construct 230/115kV Sub at Lake Murray with 336MVA Transformer– Fold-in V.C. Summer-Edenwood 230kV Line at Lake Murray– Fold-in Saluda Hydro-Cromer Road and McMeekin-Lyles 115kV Lines– Construct new 115kV Line from Lake Murray to Lexington Sub

• Benefits:– Provides up to 336 MVA Continuous Transformation from 230 to 115kV– Supports Denny Terrance and Lyles 230-115kV Transformation and

downtown 115kV corridor– Supports Lexington Area– Supports NW Columbia (Irmo, Whitehall, and Woodland Hills)


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitHopkins 230/115 kV Transmission Substation and Lines


• Outage the Columbia Industrial Park 230/115kV transformer and the Columbia Industrial Park-Edenwood 115kV Line


• Overload the Saluda to Columbia Industrial Park 115kV line• Other overloaded facilities


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitHopkins 230/115 kV Transmission Substation and Lines

• Solution:– Construct 230/115kV Sub at Hopkins with 336MVA Transformer– Fold-in to the Wateree-Columbia Energy Center 230kV line– Re-terminate the Veridian-Westinghouse 115kV line at Hopkins– Re-terminate Westinghouse-Square D tap 115kV line at Hopkins– Construct a new 115kV Line from Hopkins-Westinghouse tap (near East Columbia

tap)– Upgrade 115kV line from Westinghouse tap-Master Foods tap

• Benefits:– Provides additional 336 MVA 230/115kV transformation for the East Columbia area– Supports Columbia Industrial Park and Edenwood 230/115kV transformation


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitLandfill 115kV Station with Breakers and 36MVAR Capacitor Bank


• Outage the Edenwood-Dunbar Road 115kV and the Lexington Junction-Lexington Industrial Park 115kV

– Result:• Low voltages in the Lexington area


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitLandfill 115kV Station with Breakers and 36MVAR Capacitor Bank

• Solution:– Construct a 115kV Switching Station with (3) Breakers– Add 36 MVAR Capacitor Bank

• Benefits:– Provide voltage support– Automate switching capability


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitDenny Terrace to Pineland 230 kV Line and add Pineland 230/115 kV #2


• Loss of the VC Summer-Pineland 230kV line and Wateree-Pontiac 230kV line

• 1 other event causes problems

– Result:• Overload the Denny Terrace-Pineland 115kV line• Low voltage in the Northeast Columbia Area


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitDenny Terrace to Pineland 230 kV Line and add Pineland 230/115 kV #2

• Solution:– Construct a Denny Terrace-Pineland 230kV line– Add a 2nd 336 MVA transformer at Pineland

• Benefits:– Provide an additional 230kV source into the Northeast Columbia

Area– Provide additional 230/115kV transformation



Charleston Area• Load: 1600 MW• Generation: 857 MW



Charleston Area Major Transmission Projects

• Pepperhill - Add 230/115kV Transformer and fold-in 115kV lines • Church Creek – Savage Road 115kV Double Circuit Line• Accabee – Charlotte St. 115kV Double Circuit and Fold-in at Hagood• Mt. Pleasant Area Improvement• Canady – Church Creek 230kV Double Circuit and Fold-in at Pepperhill


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitPepperhill - Add 230/115kV Transformer and fold-in 115kV lines


• Summerville 230/115kV transformer #1 and Goose Creek-Ashley Phosphate115kV line

• 4 other events cause problems

– Result:• Overload the Summerville 230/115kV transformer #2• Other overloaded facilities


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitPepperhill - Add 230/115kV Transformer and fold-in 115kV lines

• Solution:– Pepperhill – Add 230/115kV 336 MVA transformer – Fold-in the existing Summerville-Goose Creek 115kV line at Pepperhill.

Upgrade the fold-in to 1272 ACSR. – Construct a new 115kV line and re-terminate Robert Bosch at Pepperhill.

• Benefits:– Provide additional 230/115kV support to the Summerville and Goose Creek

Areas.– Postpone several transmission upgrades in the Summerville Area.


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitChurch Creek – Savage Road 115kV Double Circuit Line


• Church Creek-Savage Road 115kV line and Hagood-Grove Street 115kV line

– Result:• Overload the Accabee-Meeting Street 115kV line


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitChurch Creek – Savage Road 115kV Double Circuit Line

• Solution:– Construct a double circuit 115kV line from Church Creek-Savage

Road. Dedicate one circuit to Savage Road Load only. The second circuit will feed St. Andrews Road Sub.

• Benefits:– Remove 50 MW of load from heavily loaded Church Creek-Bee

Street 115kV line.


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitAccabee – Charlotte St. 115kV Double Circuit and Fold-in at Hagood


• Outage the Hagood-Grove Street 115kV line and the Church Creek-Stono Park 115kV line

– Result:• Overload Accabee-Charlotte Street 115kV line


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitAccabee – Charlotte St. 115kV Double Circuit and Fold-in at Hagood

• Solution:– Construct a 115kV double circuit line from Accabee to Charlotte

Street. Fold-in one of the circuits at Hagood Plant.

• Benefits:– Provides an additional 115kV source line to support the downtown

Charleston load.– Provides Hagood generation an additional path to serve eastern part

of the downtown Charleston area.


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitMt. Pleasant Area Improvement


• Outage the AM Williams-Mt Pleasant 115kV #1 and #2 lines• 3 other events cause problems

– Result:• Overload the Charlotte Street-Mt Pleasant 115kV line


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitMt. Pleasant Area Improvement

• Solution:– Construct Thomas Island-Hobcaw 115kV line segment – Construct Osceola Tap-Hamlin 115kV line– Upgrade a section of the Charlotte Street-Bayview 115kV line to larger conductor

• Benefits:– Create an additional 115kV source to support the Mt Pleasant Area


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitCanady – Church Creek 230kV Double Circuit and Fold-in at Pepperhill


• Outage AM Williams 230kV Generation and Pepperhill-Mateeba 230kV line• 2 other events cause problems

– Result:• Overload Canady-Church Creek 230kV line• Other overloaded facilities


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitCanady – Church Creek 230kV Double Circuit and Fold-in at Pepperhill

• Solution:– Reconstruct and upgrade the Canady-Church Creek 230kV line as

double circuit. Fold-in one of the circuits at Pepperhill.

• Benefits:– Provide additional 230kV source to support the Charleston Area.– Eliminate overloaded lines into the Charleston Area.



Other Areas

• Load: 1500 MW• Generation: 2,418 MW


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitMajor Transmission Projects

• Barnwell – SRS 115kV Line• Urquhart – Belvedere 115kV Double Circuit• Graniteville – Add 230/115kV #3 transformer• Yemassee – Add 230/115kV #3 transformer• Yemassee – Beaufort 115kV Double Circuit• Ritter – Add 230/115 kV transformer


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitBarnwell – SRS 115kV Line


• Outage the Cope to Denmark115kV line and the Salem to Barnwell 115kV line


• Low Voltage in the Barnwell Area


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitBarnwell – SRS 115kV Line

• Solution:– Construct SRS to Barnwell 115kV line

• Benefits:– Provides an additional 115kV source to support the

Barnwell/Denmark Area.


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitUrquhart – Belvedere 115kV Double Circuit


• Outage the Urquhart to Graniteville 230kV line and the Urquhart to Langley 115kV line


– Result:• Overload the Urquhart to Belvedere Switching Station 115kV line• Other overloaded facilities


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitUrquhart – Belvedere 115kV Double Circuit

• Solution:– Reconstruct the Urquhart-Belvedere Switching 115kV line as double

circuit

• Benefits:– Provides Belvedere and Graniteville stronger 115kV support from

Urquhart


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitGraniteville – Add 230/115kV #3 transformer


• Outage one of the Graniteville 230/115kV transformers and the Graniteville-Ward 230kV line


– Result:• Overload the remaining Graniteville 230/115kV transformer


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitGraniteville – Add 230/115kV #3 transformer

• Solution:– Add Graniteville 230/115kV #3 transformer

• Benefits:– Provides additional 336 MVA of 230/115kV transformation at

Graniteville


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitYemassee – Add 230/115kV #3 transformer


• Outage the Yemassee 230kV Bus #2• 1 other event causes problems

– Result:• Overload the Yemassee 230/115kV transformer #1


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitYemassee – Add 230/115kV #3 transformer

• Solution:– Add Yemassee 230/115kV #3 transformer

• Benefits:– Provides additional 230/115kV 336 MVA source to Yemassee


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitYemassee – Beaufort 115kV Double Circuit

• Problem:– Yemassee-Beaufort 115kV #1 and #2 lines are two of the most operated

lines on SCE&G’s transmission system

– Contingency:• Outage of the Yemassee-Beaufort 230kV line and the Yemassee-

Beaufort 115kV line #2• 3 other events cause problems

– Result:• Overload the Yemassee-Beaufort 115kV line #1


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitYemassee – Beaufort 115kV Double Circuit

• Solution:– Reconstruct the Yemassee-Beaufort 115kV line #2 as double circuit

• Benefits:– Provides additional 115kV support to the Beaufort Area.– Replaces poor performing lines


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitRitter 230/115 kV Transmission Substation


• Outage the Canadys-Forest Hills 115kV line and the Church Creek-Rantowles 115kV line


– Result:• Overload the Yemassee-Ritter 115kV line• Low Voltage in the Walterboro and Adams Run Area


SCE&G Transmission Planning SummitSCE&G Transmission Planning SummitRitter 230/115 kV Transmission Substation

• Solution:– Add Ritter 230/115kV transformer at the existing Ritter 115kV

Substation

• Benefits:– Provides an additional 115kV source to the Walterboro and Adams

Run Area.– Improve voltage condition during contingencies



Closing Comments

Documents

SCE&G Transmission Planning Summit - … Hydro 10MW Coit Turbines 32MW ... transformer connected to the Transmission System: ... SCE&G Transmission Planning Summit