Delivering Power For Texas’ Future, Tutorial on 765 kV Transmission

ERCOT Regional Planning Group CREZ Meeting September 28, 2007

Presenters

• Calvin Crowder, – AEPSC Executive Director, ETT – Introduction of presenters • Scott Moore, – AEPSC VP Transmission System & Region Operations – Operational Experience with 765 kV • Navin Bhatt, PhD – AEPSC Manager, Advanced Transmission Studies & Technologies – Planning Considerations for 765 kV • Paul Hassink, – AEPSC Manager, Texas Transmission Planning – Applications of 765 kV to CREZ 2

CREZ Challenges

• Efficiently collect and transport wind energy AND develop a robust transmission system to deliver the energy to load • Pioneer the long-term vision of a Transmission Superhighway for the 21 st Century • Build transmission in manner, addressing: the most cost effective  future generation development  pockets of rapid load growth  market efficiency (reduce congestion costs)  competitive wholesale markets  economic growth in the State of Texas 3

Why 765 kV can meet the CREZ Challenge

• Proven Technology  765 kV system operating since 1969 at AEP  Decades of experience worldwide; China, Brazil, S. Africa, Venezuela, Canada, Russia • Operational & Planning Flexibility  Addresses transmission congestion by unloading the existing bulk transmission system  Reduces losses resulting in production cost savings   Enables unconstrained interconnection for generation Provides connections to the existing 345 kV infrastructure wherever appropriate 4

AEP’s 765 kV Grid

2,100 miles of 765kV Across 6 states in PJM

( Accurate 2005) Jacksons Ferry-Wyoming 90-mile 765 kV transmission line placed in service June 20, 2006 5

Building an Interstate Transmission System: AEP’s I-765 ™ Concept

PJM PATH Project AEP-ITC Michigan Proposal

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SPP Overlay Study

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Operational Experience with 765 kV

Scott Moore,

AEPSC VP Transmission System & Region Operations

Operational Experience with 765 kV

• Unloads underlying network  Improved loading margins on lower voltage network • Single Phase switching and operation • Virtually no risk of thermal overload   Even heavily loaded 765 kV lines operate near ambient temperature Minimal line sag; tree contact less likely • Demonstrated Network Strength  8/14/03 blackout 9

8/14/03 Northeast Blackout

• Affected approximately 50 million people in 8 states and 2 provinces.

• 60-65,000 MW of load initially interrupted • Approximately 11% of Eastern Interconnection • 400+ transmission lines tripped • 531+ generating units at 261 plants tripped • High speed cascading lasted approximately 12 seconds 10

Conditions Prior to Blackout

• Electric demands high, but not unusually high  System was within limits prior to 3:05 PM, on both actual and contingency basis • Power transfer levels high,  but within established limits & previously experienced levels • Critical voltage day   Voltages within limits Operators taking action to boost voltages • Frequency  Typical for a summer day 11

East Lake 5 Trip: 1:31:34 PM

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Major Path to Cleveland Blocked after Loss of Sammis-Star 4:05:57.5 PM Remaining Paths

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345 kV Lines Trip Across Ohio to West

ONTARIO 14

Generation Trips 4:09:08 – 4:10:27 PM

ONTARIO 15

345 kV Transmission Cascade Moves North into Michigan 4:10:36 – 4:10:37 PM

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Northern Ohio and Eastern Michigan Served Only from Ontario after 4:10:37.5 – 4:10:38.6 PM

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Analogous to a Fire Break

• While other transmission systems opened under heavy transfers, the 765 kV system remained intact • The 765 kV system became the barrier that stopped the cascade from moving south • With virtually no risk of thermal overload, the 765 kV system demonstrated its network strength 18

Single Phase Switching

• 95 % of faults on 765 kV are single phase • Single phase tripping of faulted phase with high speed reclose • Two thirds of power is not interrupted during the trip and reclose cycle.

• Underlying network is not materially effected 19

Planning Considerations for 765 kV

Navin Bhatt, PhD

AEPSC Manager, Advanced Transmission Studies & Technologies

Planning Considerations

Outline

• Planning with 765 kV  Advantages of 765 kV  Generation Integration with 765 kV 21

Planning with 765 kV

1. High Load Carrying Capacity (Loadability) St. Clair Curve

22

Loadability (St. Clair Curve)

• Valid for 138-765 kV Lines • Surge Impedance Loading (SIL) VS. Line Length • Considers – Line Voltage Drop Limitation – Steady-State Stability Limitation Line Length 50 (Miles) 3 (PU SIL) 100 150 200 300 Loadability 2 1.6

1.3

1 23

Loadability (St. Clair Curve)

• SIL - 345 kV Double Circuit (DCT) = 800 MW • SIL - 765 kV Single Circuit = 2400 MW • Loadability of 100-Mile Long Line  1600 MW for 345 kV DCT  4800 MW for 765 kV 24

Planning with 765 kV

2. Favorable ROW Requirements

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Planning with 765 kV

3. Favorable Visual Impact Double-circuit 345 kV line that uses lattice towers is 170 feet tall, while a 765 kV line using lattice towers is 127 feet tall

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Planning with 765 kV

4. Lower Cost ($/MW Delivered)

27

Planning with 765 kV

5. Line Loss Savings

• 765 kV Line Resistance - - Lower compared to 345 kV • Latest 6-conductor bundle more efficient than early design • Unloading of underlying network • AEP System Savings Due to 2100-Mile of 765 kV Lines, Compared to 345 kV Lines – 220 MW of Generating Capacity – 830,000 MWH/Year of Energy Consumption – $37M Annual Savings – 425,000 Tons/Year Reduction in CO 2 28

Planning with 765 kV

6. Favorable Forced Outage Statistics

  Lower likelihood & severity of circuit disruption Improved line reliability/availability through single phase switching 765 kV: 1 outage per year per 100 miles 345 kV: 1.6 outages per year per 100 miles (Source: 1993 IEEE Paper, “An IEEE Survey of U.S. and Canadian Overhead Transmission Outages at 230 kV and Above.”) 29

Generation Integration with 765 kV

• 17,000 MW generation integrated through AEP’s 765 kV network • Gavin-Flatlick-Monutaineer Generation Complex = 4,800 MW • Gavin-Flatlick 765 kV Line = 15 Miles • Gavin-Mountaineer 765 kV Line = 11 miles 30

Generation Integration with 765 kV Gavin-Flatlick Monutaineer Generation Complex = 4,800 MW

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Generation Integration with 765 kV

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Generation Integration with 765 kV Using St. Clair Loadability Curve

• Integration of 4800 MW Generation  345 kV DCT – 3 Lines  1600 MW (or 2 PU SIL) per line  Corresponding line length = 100 miles  “Generation reach” = 100 miles  765 kV – 3 Lines  1600 MW (or 0.67 PU SIL) per line  Corresponding line length = 500 miles  “Generation reach” = 500 miles  765 kV – 2 Lines  2400 MW (or 1.0 PU SIL) per line  Corresponding line length = 300 miles  “Generation reach” = 300 miles 33

Generation Integration with 765 kV Bottom Line:

• 765 kV enables interconnection of

more generating capacity with less transmission lines

• 765 kV provides flexibility in siting

& delivering generation

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Experience at Rockport Generating Plant

• Generator Installation  Located in Southern Indiana  1300 MW in 1884 & 1300 MW in 1987  Steel Mill Load (110 MW) Connected at 138 kV • Two (2) 765 kV Transmission Lines  Rockport-Jefferson Line (110 Miles)  Rockport-Sullivan Line (97 Miles) • Challenge:  Operating the plant with only 2 outlets  Designing stability controls  Making sure all controls work as expected 35

Rockport Plant Rockport Generating Plant 1300 MW in 1884 & 1300 MW in 1987

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Experience at Rockport Generating Plant

• Stability Controls Implemented  improve plant stability & voltage performance  maximize plant output • Generator Systems  Fast valving  Rapid unit runback  Emergency unit tripping 37

Experience at Rockport Generating Plant

• Single-phase-switching implemented on both Rockport 765 kV lines • Results: 3 plant trip-outs since 1987 • None related to line performance • Bottom Line: Savings

High capacity, reliable 765 kV lines have allowed the Rockport plant to operate successfully with only 2 outlets for over 2 decades

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Advanced Technologies for 765 kV Application

• 6-Conductor Phase Bundle • Phase & Shield Wire Transposition • Fiber-Optic Shield Wires • Wide Area Monitoring & Control • Remote Equipment Diagnostics • Independent Phase Operation • Voltage Compensation & Control for

Optimum Steady-State & Dynamic Support

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Summary of 765 kV Technology

• Proven, Reliable, Efficient • Highest capacity; Lowest land use per MW • Ideal for: • integrating large amount of generation • transporting large amounts of power over long

distances

• Provides planning & operational flexibility • Easy to integrate with existing underlying

network

• Provides flexibility to integrate future

transmission & generation infrastructure growth

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Applications of 765 kV to CREZ

Paul Hassink,

AEPSC Manager, Texas Transmission Planning

CREZ Applications of 765 kV Outline

• Pre-CREZ Constraints • Alternative Analysis of 345 kV vs 765 kV • 765 kV Transmission Information 42

CREZ Base Case Assumptions

• Existing 345 kV system in West Texas is exhausted at about 5 GW of wind generation   Assuming that West to East power flow diverted away from 138 kV and 69 kV systems, and Oklaunion to Bowman 345 kV line is constructed • Pre-CREZ transmission upgrades include   Isolation of the 138 kV system from the 345 kV system where practical Upgrades to the 138 kV system in the path of West to East power flow 43

138 kV System Upgrades

• Bypass Red Creek with Ballinger to Ben Flicken 138 kV line • Split SAPS bus to separate West and East 138 kV systems • Add Abilene Plant to Putnam 138 kV circuit on existing 69 kV line • Upgrade limiting segment of Paint Creek to Murray to Graham 138 kV line • Rebuild Oran to Barton to Graham 138 kV line • Add 138 kV circuit to Stephenville to Comanche Switch 345 kV line and open Comanche Switch 345/138 kV autotransformer 44

345 kV Constraints

Limiting 345 kV Circuit

Willow Creek to Jacksboro Graham to Long Creek Willow Creek to Parker Graham to Benbrook Bowman to Jacksboro

West Texas Wind Generation (MW)

5,100 5,200 5,200 5,500 5,600 45

CREZ Base Case Assumptions

• At 6 GW of West Texas Wind Generation and ERCOT minimum load of 30 GW  All simple cycle and significant amounts of combined cycle gas generation is offset   Remaining gas and solid fuel generation should be retained to maintain system security An incremental 12 GW of wind generation requires additional load in order to securely operate ERCOT across the minimum hour • Level 2 of CREZ as proposed by the PUCT is an incremental 12 GW of wind generation above a 2008 level of approximately 6 GW  Roughly 5 GW in Zones 1, 2, & 4   Nearly 5 GW in Zones 9, 10, & 19 Nearly 2 GW in Zones 5 & 6 46

Components of CREZ Transmission

• Backbone transmission system   Facilitates the infrastructure needed to serve load growth in areas of new development Supports the 20+ years of load needed to absorb 12 GW of incremental wind generation • Transport system goals   Avoid further burdening existing 345 kV infrastructure Collect the most wind energy for the least cost 47

Alternative Analysis

• Two Transport System Alternatives  345 kV double circuit 5000 a terminals  765 kV single circuit 4000 a terminals • Backbone transmission system  765 kV with three deliver points  Unchanged between alternatives • Wind generation scaled from 6 GW up to 18 GW, incrementally 12GW 48

Mid-Level CREZ adopted by PUCT +2.9GW

Incremental Transfer of Wind to Load

+12GW -12GW

+2.4GW

-6GW +4.8GW

-5GW

Backbone Lines Transport Lines Load Growth CREZ

+1.9GW

-1GW

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Transport System Constraints

Line Rating - Alternative Limit (MW) Limiting Circuit

Clear Crossing to Graham Long Creek to Graham Graham to Parker Oklaunion to Clear Crossing Graham to Benbrook Bowman to Jacksboro Jacksboro to Willow Creek Comanche Switch to Comanche Peak Willow Creek to Parker Morgan Creek to Sweetwater Mulberry Creek to Long Creek Sweetwater to Graham Bitter Creek to Mulberry Creek Morgan Creek to Clear Crossing

345 kV

11,900 12,300 12,900 13,500 13,900 14,000 14,400 14,700 14,800 15,400 15,700 15,900 16,300 16,600

765 kV

16,800 15,100 15,600 >18,000 16,700 >18,000 17,500 >18,000 17,900 >18,000 >18,000 >18,000 >18,000 >18,000

Increase

4,900 2,800 2,700 >4,500 2,800 >4,000 3,100 >3,300 3,100 >2,600 >2,300 >2,100 >1,700 >1,400 The usual 345 kV line segments are the limiting elements 50

Transport System Constraints

Voltage Stablity - Alternative Limit (MW) Limiting Contingency 765 kV

CREZ #4 to Oklaunion line Buchanan to Comanche Switch line San Angelo to Buchanan line Graham to Mesquite line Mulberry Creek to Graham line San Angelo to Buchanan circuit Ranger to Comanche Peak line Comanche Switch to Ranger line Bluff Creek to Ranger line Spring to Oklaunion line Clear Crossing to Ranger line 17,400

345 kV

14,000 16,700 16,700 17,100 17,200 17,200 17,200 17,200 17,200 17,400 18,000 Wind Generation levels were derived employing unlimited shunt reactive support and the application of series compensation on the Panhandle to DFW 345 kV segments of the transport system. 51

Observations from Alternative Analysis

• Line Rating  Transport lines for both alternatives appear to be adequate, if line rating = 5 GVA (2x2500@345 kV)   The existing 345 kV system in and out of Graham is the most constraining condition for both 345 kV and 765 kV alternatives.

The 765 kV alternative has at least a 3 GW advantage over the 345 kV alternative and 5 GW and greater advantage except for Long Creek and Willow Creek • Voltage Stability  Both alternatives are most stressed for loss of the most southern leg from San Angelo to Austin  The 345 kV alternative is stressed for 11 different contingencies, and much more like to be Transient Stability limited 52

765 kV Transmission Information

Typical 765 kV Transmission Line Cost ($000/mile) Engineering & Right-of-way Materials & Administration Acquisition Construction

80 278 2,242

TOTAL

2,600

Typical 765 kV Substation

Station equipment required including breakers, reactors, buswork, P&C and site Typical autotransformer with 4-765/345kV 500MVA single phase units

($000)

40 20

765 kV Line Data

Conductor Structure Max Op Temp circuit 95°C Wind Speed Conductor Rating Terminal Rating Compensation per 100 mile 3 ft/s @ 60° 10,900 MVA 4000 a 300 Mvar 53

Additional Losses at 345 kV Compared to 765 kV

Power Losses (MW)

1200 1000 800 600 400 200 0 6 12

Wind (GW)

18 54

Summary

• Long term transmission planning provides a more efficient, environmentally-friendly, lower cost grid • 765kV has a clear role in the ERCOT grid • ETT looks forward to working with stakeholders to advance the transmission superhighway of the 21 st century 55