Northwest Quadrant Joint Security Study Southern Company Headquarters Birmingham, Alabama August 12,...

Northwest QuadrantNorthwest QuadrantJoint Security StudyJoint Security Study

Southern Company HeadquartersSouthern Company HeadquartersBirmingham, AlabamaBirmingham, AlabamaAugust 12, 2002August 12, 2002Presented by Saeed ArabiPresented by Saeed Arabi

2 Powertech Labs Inc.

OutlineOutline

ScopeScope

AssumptionsAssumptions

ResultsResults

Proposed SolutionsProposed Solutions


Joint Security Study ScopeJoint Security Study Scope

Identify critical contingencies and constraintsIdentify critical contingencies and constraints• Scanning about two-thirds of the State of Alabama, the Scanning about two-thirds of the State of Alabama, the

extreme northwest portion of Georgia, and a small portion of extreme northwest portion of Georgia, and a small portion of eastern Mississippieastern Mississippi

Determine generation limits for various system Determine generation limits for various system conditionsconditions

Define the boundary of the security problemDefine the boundary of the security problem• SensitivitiesSensitivities• Worst-case scenarioWorst-case scenario

Propose solutions to stability constraintsPropose solutions to stability constraints


Joint Security Study AssumptionsJoint Security Study Assumptions

2003 peak and 50% of expected peak (off-peak) load 2003 peak and 50% of expected peak (off-peak) load level cases usedlevel cases used

• Off-peak case based upon economic dispatchOff-peak case based upon economic dispatch• PSS assumed to be available on all new unitsPSS assumed to be available on all new units

New units were added to the NWQ according to a New units were added to the NWQ according to a joint queue developed by the 3 companiesjoint queue developed by the 3 companies

• Firm Transmission Service confirmedFirm Transmission Service confirmed• Firm Transmission Service requestedFirm Transmission Service requested• Interconnection confirmedInterconnection confirmed• Interconnection requestedInterconnection requested

To validate stability results, “hypothetical” thermal To validate stability results, “hypothetical” thermal upgrades were added to relieve thermal constraints.upgrades were added to relieve thermal constraints.

• Not a thermal study!Not a thermal study!


Joint Security Study Assumptions Joint Security Study Assumptions (cont)(cont)

Four “Normal” source/sink scenariosFour “Normal” source/sink scenarios• EST-EST: Sink generation in the company territory where it is EST-EST: Sink generation in the company territory where it is

locatedlocated• EST-E: Sink generation in EntergyEST-E: Sink generation in Entergy• EST-S: Sink generation in SouthernEST-S: Sink generation in Southern• EST-T: Sink generation in TVAEST-T: Sink generation in TVA

One “Worst” source/sink scenarioOne “Worst” source/sink scenario• EST_W-S: Source ordered by TDFEST_W-S: Source ordered by TDF

Do not violate interface capacities of 3 companiesDo not violate interface capacities of 3 companies


Standard criteria usedStandard criteria used• Used each company’s current and voltage ratings and limitsUsed each company’s current and voltage ratings and limits• Voltage collapse margin: 5% Voltage collapse margin: 5% • Transient voltage dips: 75% for < 40 cyclesTransient voltage dips: 75% for < 40 cycles• Minimum damping: 3% Minimum damping: 3% • Fault clearing margin: 2 cyclesFault clearing margin: 2 cycles

Combinations of constant power, current, and Combinations of constant power, current, and impedance load models usedimpedance load models used

Joint Security Study Assumptions Joint Security Study Assumptions (cont)(cont)


The most limiting contingency from a damping standpoint The most limiting contingency from a damping standpoint was the Miller - Bellefonte 500 kV line was the Miller - Bellefonte 500 kV line (Line tripping event)(Line tripping event)

The most limiting contingency from a transient voltage The most limiting contingency from a transient voltage dip standpoint was the Farley – Raccoon Creek 500 kV dip standpoint was the Farley – Raccoon Creek 500 kV line line (Normally cleared 3ph fault)(Normally cleared 3ph fault)

The most limiting normal scenario identified was EST-S The most limiting normal scenario identified was EST-S (Sinking to Southern under off-peak conditions)(Sinking to Southern under off-peak conditions)

SVC will raise stability limit some – Big increases will SVC will raise stability limit some – Big increases will require 500 kV linesrequire 500 kV lines

Joint Security Study ResultsJoint Security Study Results


New generation added without PSS severely deteriorated New generation added without PSS severely deteriorated system damping: PSS requiredsystem damping: PSS required

Limit is very source/sink dependent: Sequential studies Limit is very source/sink dependent: Sequential studies requiredrequired

5625 MW “Normal” limit based on the joint EST Queue5625 MW “Normal” limit based on the joint EST Queue

3500 MW “Worst” limit based on TDF of Farley-Raccoon 3500 MW “Worst” limit based on TDF of Farley-Raccoon LineLine (Limits are above year 2000 generation)(Limits are above year 2000 generation)

Line re-conductoring had small impact on security limitsLine re-conductoring had small impact on security limits

Table 3-2Table 3-2 w/ PSSw/ PSS w/o PSSw/o PSS

EST-SEST-S >9500>9500 00

Joint Security Study Results Joint Security Study Results (cont)(cont)


Buf. Case Scenario Contingency

Bus # Bus Name Buf.Bus voltage magnitude (pu)

Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000

1.250Bus voltage magnitude (pu)

Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000

1.250

1 50% of 2003 Expected Peak Load. EST-EST Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 1

2 50% of 2003 Expected Peak Load. EST-E Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 2

3 50% of 2003 Expected Peak Load. EST-S Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 3

4 50% of 2003 Expected Peak Load. EST-T Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 4



Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000

1.250

1 50% of 2003 Expected Peak Load. EST-EST Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 1

2 50% of 2003 Expected Peak Load. EST-E Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 2

3 50% of 2003 Expected Peak Load. EST-S Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 3

4 50% of 2003 Expected Peak Load. EST-T Without PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 4

Joint Security Study Results Joint Security Study Results (cont)(cont)



Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000

1.250

1 50% of 2003 Expected Peak Load. EST-EST With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 1

2 50% of 2003 Expected Peak Load. EST-E With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 2

3 50% of 2003 Expected Peak Load. EST-S With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 3

4 50% of 2003 Expected Peak Load. EST-T With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 4



Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000


Time in seconds

0.000 4.000 8.000 12.000 16.000 20.0000.000

0.250

0.500

0.750

1.000

1.250

1 50% of 2003 Expected Peak Load. EST-EST With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 1

2 50% of 2003 Expected Peak Load. EST-E With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 2

3 50% of 2003 Expected Peak Load. EST-S With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 3

4 50% of 2003 Expected Peak Load. EST-T With PSS for IPP&NLs 15: 94600-96280

90218 S BAINBR230. 4


Joint Security Study- Proposed SolutionsJoint Security Study- Proposed Solutions

Dynamic shunt compensation can increase the transient Dynamic shunt compensation can increase the transient security limit by 1400 – 2150 MW security limit by 1400 – 2150 MW (In South Bainbridge and Auburn (In South Bainbridge and Auburn

regions)regions)

• Minimal increase after 900 Mvar addedMinimal increase after 900 Mvar added• 230 kV re-conductoring and static capacitors would be required230 kV re-conductoring and static capacitors would be required• Cost of SVC: Approximately $5 million per 100 MvarCost of SVC: Approximately $5 million per 100 Mvar

Series compensation was evaluated, but found to not be Series compensation was evaluated, but found to not be an effective solutionan effective solution

• Candidate lines were already heavily loadedCandidate lines were already heavily loaded


8,8688,8688,8688,8688,8208,8208,6928,6928,6788,6787,7287,728Voltage Stability Voltage Stability

(with 5% Margin)(with 5% Margin)

7,6007,6007,6007,6007,6007,6007,2507,2507,2507,2507,1507,150Thermal *Thermal *

(at 120% Loading)(at 120% Loading)

7,7747,7747,5897,5897,2097,2096,8406,8406,6706,6705,6255,625Transient Security Transient Security

(Voltage Dip)(Voltage Dip)

8,3508,3508,3508,3507,7007,7007,0007,0007,0007,0004,3004,300Voltage Magnitude Voltage Magnitude (0.9 pu)(0.9 pu)

200 & 200 & 900900

300 & 300 & 700700

400 & 400 & 500500

200 & 200 & 300300

300 & 300 & 100100

0 & 0 & 00

Shunt Compensation by MSC & TSC (MVAr)Shunt Compensation by MSC & TSC (MVAr)

Limit TypeLimit Type

Table 4‑2: Shunt Compensation and EST–S Scenario Limits (MW) – Various Phenomena Table 4‑2: Shunt Compensation and EST–S Scenario Limits (MW) – Various Phenomena for Contingency 15 (Critical Path Highlighted).for Contingency 15 (Critical Path Highlighted).

Critical Path Limits With Shunt Critical Path Limits With Shunt CompensationCompensation

* Not representative of thermal studies for specific transfers. * Not representative of thermal studies for specific transfers.


Questions?Questions?


Northwest QuadrantNorthwest Quadrant


BackgroundBackground

Southern company internal studies indicated ~5000 Southern company internal studies indicated ~5000 MW of new generation above year 2000 before MW of new generation above year 2000 before transient stability limit reachedtransient stability limit reached

~20,000 MW of new generation requests in the NWQ~20,000 MW of new generation requests in the NWQ

Joint study initiated with Powertech Labs last summerJoint study initiated with Powertech Labs last summer

Entergy and TVA included in the study and modelEntergy and TVA included in the study and model

TSR facility studies on hold pending the results of the TSR facility studies on hold pending the results of the joint studyjoint study

Northwest Quadrant Joint Security Study Southern Company Headquarters Birmingham, Alabama August 12,...

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