Long Term Study Task Force Update Transmission Study Practices and Methodologies April 5th,2011 LTS

Long Term Study Task Force Update

Transmission Study Practices and Methodologies

April 5th,2011

LTS

Objectives

• Create a stable, reliable representation of the ERCOT System for the 2020 and 2030 horizon.

• Integrate a generation portfolio representative of the real energy needs of the 2020 and 2030 loads while maintaining an appropriate reserve margin

• Identify Transmission Solutions that meet the long term needs of the ERCOT system

• Evaluate the AC steady-state reliability needs of the system, and develop solutions that minimize total economic cost (by scenario)

LTS April 5th,20112

Process

LTS April 5th,2011

Develop Transmission Model

Perform Simplification Criteria

2016 SSWG Case

Load Forecast 2020/30 Install Generation

needed to meet real energy needs

Determine Transmission Needs

Implement and document results

Map case to Security Constrained Economic Dispatch Model (Promod)

Remove and Replace generation added for Reliability

Scenario Specific Economic Build Out

Generation Siting Process

Reassess Transmission Needs – Reliability and Economy

Defined Contingencies

Prepare final solution set

3

Load Forecast Development

• Load forecasts developed by weather zone

Included input from 15 years of weather data (1996-2010)

• Calculated Average, max, and min temperatures

• Applied median (50 percentile) temperature per weather month

• Loads were disaggregated by county (using Moody’s population data) and applied at the appropriate bus / equivalent bus in those counties

LTS April 5th,20114

2016 vs 2020

LTS April 5th,2011

2016: 1,984 MW 2020: 2,078 MW

2016: 3,112 MW 2020: 3,345 MW

2016: 21,106 MW 2020: 22,358 MW

2016: 5,947 MW 2020: 6,423 MW

2016: 2,294 MW 2020: 2,420 MW

2016: 2,052 MW 2020: 2,194 MW

2016: 27,273 MW2020: 29,185 MW

2016: 12,783 MW 2020: 14,115 MW

Non-coincident peak load2016: 76,551MW 2020: 82,118 MW

5

2016 vs 2030

LTS April 5th,2011

2016: 1,984 MW 2030: 2,174 MW

2016: 3,112 MW 2030: 3,777 MW

2016: 21,106 MW 2030: 24,466 MW

2016: 5,947 MW 2030: 7,409 MW

2016: 2,294 MW 2030: 2,637 MW

2016: 2,052 MW 2030: 2,461 MW

2016: 27,273 MW2030: 33,856 MW

2016: 12,783 MW 2030: 16,524 MW

Non-coincident peak load2016: 76,551MW 2030: 93,304 MW

6

Transmission Simplification Criteria

• Equivalence the 69kV System: All 69kV Loads and Generators are replaced at the nearest upstream 138kV or 345kV Bus

• Equivalence rural / radial lines (138kV): – Rural lines less than 30 miles rated less than 150MVA are

upgraded to 300MVA. – Rural lines less than 20 miles rated less than 440 MVA are

upgraded to 440 MVA– Any rural line with a rating higher than 440 is not upgraded

• Upgrade short urban lines (138kV): Any urban line shorter than 2.5 miles rated less than 800MVA is upgraded to 800MVA

LTS April 5th,20117

Reliability Screen – Generation additions

Increased loads are served by incremental generation added as follows:

•Selected existing generation sites are rebuilt as larger machines where practical

•Where excess transmission capacity exists, new generators are added

•For large load centers of interest, multiple generation sites are tested independently to identify worst case scenarios

Where:

fuel, cooling, existing transmission, and proximity to a major metropolitan area allow

LTS April 5th,20118

2020 and 2030 AC Cases

• Voltage issues and thermal limitations are corrected where necessary– Reactive support is applied at the worst offending busses in an

iterative approach to correct voltage to .98 PU (N-0)– Address thermal overloads, as well as voltage collapse for (N-1)

• Cases are stable, reliability assessment is underway– Includes N-1, G-3 stress testing of the steady-state model– NERC C & D criteria will be tested with proposed solutions

• Cases will be mapped to ProMod, with the newly developed contingency file, to determine opportunities for economic projects

LTS April 5th,20119

Transmission Simplification Validation

• Verify no material changes in system dispatch: Pre and post simplification models are compared to verify no material changes in production cost or dispatch occurred as a result of the simplification

• Preliminary comparisons are in Uplan, subsequent comparisons will be performed pre and post simplification in ProMod

LTS April 5th,2011

Case Description Difference in Production cost from Base Case(M$)

Base Case Full System -

Partially Simplified Full system - 69kV system 107.87 Fully simplified Full system - 69kV system +

simplified 138kV system129.96

10

Development of Contingency Events

• To maintain a plausible system dispatch, constraints must be defined to reflect new contingencies or redefine contingencies eliminated in the simplification process

• Previous study practices defined many contingencies with emphasis on any element with post-contingency loading beyond a user defined threshold.

• New tools (PAT, ProMod) and study practices focus on an iterative approach to define specific, targeted contingencies

• Increased engineering input allows system modeling with sufficient detail and decreased run times, allowing for additional analysis on specific topics and scenarios

LTS April 5th,201111

Economic Analysis

• Perform a security constrained economic dispatch study of the simplified transmission model with the updated generation portfolio

• Identify transmission projects that create societal benefit (measured as decreased system production cost)

• Analyze opportunities to replace a previously modeled reliability project with a project that meets both economic and reliability needs

• Benchmark each project against alternatives in each scenario


Large Load Centers Currently in Study

• DFW Metro Area

• Houston Metro Area

• Lower Rio Grande Valley


Dallas Fort Worth Metro Area

• Voltage deficiencies are significant and not correctable from incremental reactive resources (~9000MVar of switched shunt compensation required for N-0)

• Potential retirement of legacy generation exacerbates voltage issues

• Studies with incremental generation or lines into the DFW are underway


Dallas Fort Worth Metro Area

As modeled, the Dallas metro area relies on heavy imports into the Region from the South and East

P A R I S _ S W 1 _ 5

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W H I T N E Y 5

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L A K E _ C R K 1 _ 5

J E W E T T _ S 5J E W E T T _ N 5

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D E C R D O V A _ T 5

C E N T U R Y 3 _ 5

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C O N C O R D

D C E A S T

L A M A R P W R _ 5

M D L T H E L P _ N 5

M D L T H E L P _ 5

M D L T H E L P _ S 5

B O S Q U E S W 5

N U C O R _ S T 1 _ 5

C O M C H P K W _ 5

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W L F H O L W _ 5

1 4 3 0

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2 4 3 2

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2 4 6 1

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2 5 2 2

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3 1 0 3

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3 4 0 0

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3 4 2 2

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1 9 1 1

2 4 0 62 4 1 0

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2 4 7 4

4 6 0 2 0

2 4 3 52 4 2 7

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3 1 3 3

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W A T M L L _ 1 T 5

3 4 0 9

W I L L O W C K _ 51 4 2 1

J A C K S B R O _ 5

1 4 2 9

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1 8 6 8

C O L L I N S S 1 _ 5

2 3 7 2

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R O Y S E _ S 52 4 7 8

F P L E F R B 1 _ 51 2 4 1 0

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R O Y S E 3 _ 5

2 4 8 3

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2 9 9 7W A T M L L _ 2 T 5

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L A K E _ C R K 2 _ 5

3 4 0 2

T E M P _ P E C _ _ 5

D E S S W 1 _ 5

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3 1 0 5

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2 5 1 42 5 1 3

T Y L E R G N D _ 53 1 0 2

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E V R M A N _ W 51 8 8 2

JASPERNEWTON

WALKER

TRINITY

POLKTYLER

ANGELINA

SAN

AU

GU

STIN

E

SABINE

SHELBBY

PANOLA

NACOGDOCHESCHEROKEE

HOUSTON

HARRISON

MARION

CASSMO

RRIS

TITUS

CAMP

FRAN

KLI

N

UPSHURWOOD

GREGG

RUSK

RED RIVER

BOWIE

FANNIN

DELTA

HUNT

RAINS

VAN ZANDT

SMITH

KAUFMAN

HOPKINS

HENDERSON

ANDERSON

NAVARRO

FREESTONELIMESTONE

LEON

ELLISJOHNSON

HILL

McLENNAN

SOMERVELL

HOOD

ERATH

COMANCHE

HAMLITON

MILLS

CORYELL

BOSQUE

BURNET

SAN SABA

McCULLLOCH

LLANO

WILLIAMSON

BELL

FALLS

MILAM

LAMPASSAS

ROBERTSON

MADISON

BRAZOS

BROWN

CALLAHAN

EASTLAND

COLLINS

ROCKWALLDALLAS

TARRANT

PARKER

PALO PINTO

JACKWISE

DENTON

GRAYSON

ARCHERBAYLOR

YOUNG

THROCKMORTON

SHACKLEFORD

STEPHENS

SNGLTN_345

W_KRUM_5

90%A

Amps

90%A

Amps

91%A

Amps

94%A

Amps

80%A

Amps

80%A

Amps

47%A

Amps

47%A

Amps

59%A

Amps

59%A

Amps

72%A

Amps 72%

A

Amps

114%A

Amps

118%A

Amps

119%A

Amps119%

A

Amps

Low Voltage Issues

Post contingency stability limit violations exist - highlighted lines represent a possible solution.

April 5th,201115LTS

Lower Rio Grande Valley

• Peaks are comparable or higher than 2011 Winter Event levels

• Current 345kV importation is not sufficient for maintenance and/or voltage stability

LTS April 5th,2011

YearUpdated Forecast extrapolated by county

2016 30872020 32942030 3941

16


L N H I L L 6

R I O H N D 6

E D N B R G 6

L A P A L M 6

W H I T E P T 6

L H E D M

L H E D L

L H R H M

L H R H L

8 4 5 5

8 3 8 3

8 3 1 8

8 3 1 7

8 9 0 1

8 9 0 5

8 9 0 3

8 9 0 2

R I O H N S T R

8 9 5 6

C I D - 2 3 08 6 1 0 5

ARANSASSAN PATRICIO

NUECES

DUVALWEBB J IM WELLS

ZAPATA

J IM HOGGBROOKS

KLEBERG

KENEDY

STARR

HIDALGO

WILLACY

CAMERON

ADC-23086103

RI OBRAV

112%A

Amps

112%A

Amps

113%A

Amps

Proposed 345 by AEP in RPG

Loss of this line causes angular

divergence

Loss of this line causes overload of the other under 2020 loads and

angular divergence under 2030 MW loads

April 5th,201117LTS


L N H I L L 6

R I O H N D 6

E D N B R G 6

L A P A L M 6

W H I T E P T 6

L H E D M

L H E D L

L H R H M

L H R H L

8 4 5 5

8 3 8 3

8 3 1 8

8 3 1 7

8 9 0 1

8 9 0 5

8 9 0 3

8 9 0 2

R I O H N S T R

8 9 5 6

C I D - 2 3 08 6 1 0 5

ARANSASSAN PATRICIO

NUECES

DUVALWEBB J IM WELLS

ZAPATA

J IM HOGGBROOKS

KLEBERG

KENEDY

STARR

HIDALGO

WILLACY

CAMERON

ADC-23086103

RI OBRAV

112%A

Amps

112%A

Amps

113%A

Amps

Double circuit increases stability limit and thermal

rating.

Double circuit increases stability limit and thermal

rating.

Tie reduces contingency impact.

Series Compensation adjusted back to 50% after adding second

circuit.

Proposed new line is does not address all issues on a 20 year horizon. Contingent

flows on this line are low due to long distance to

generation.

April 5th,201118LTS

Houston under 2030 Load + 5%

• Large amounts of shunt reactive compensation, some likely dynamic, appears necessary.

• Preliminary analysis indicates that a new import path will be needed before 2030 to solve angular stability issues on the north (Singleton) and west (Fayette) import paths

• Analysis is ongoing

April 5th,201119LTS

Future Economic Studies

• Map the simplified transmission model to Promod

• Remove and replace any generation added for stability with generation fuel / location derived from Promod results.

• Perform a Promod run, identifying LMP values at each bus

• Identify opportunities for economic projects


Questions?


Documents

Long Term Study Task Force Update Transmission Study Practices and Methodologies April 5th,2011 LTS