Sharyland Utilities’HVDC Interconnection: Part 1

Sharyland Utilities, L.P.

• Newest Investor Owned Utility in Texas

• A “greenfield” utility focusing on power reliability

• Our Service Territory is encompassed by the Master Planned Development of Sharyland Plantation

South Texas Location

• Located in the Cities of Mission and McAllen, TX

• Directly across the border from Reynosa, Tamaulipas, MX

• 150 miles from Financial and Industrial Center of Monterrey, Nuevo Leon, MX

The Master Plan

• South Texas Metro Area– Young Work Force– Economy

• Reynosa, Tamaulipas, MX– Large Industrial Parks– Fortune 500 Companies

• Monterrey, Nuevo Leon, MX– Industrial Center

What is an HVDC Tie?

• Power transfer between grids (states/countries)

• Provides “firewall”protection for each side

• Neglects the system characteristics to allow them to be matched. (Asynchronous Tie)

South Texas Infrastructure

Mexico and United States Border Region CFE/ERCOT

S. Lane City

Austrop

KendallSan Marcos

Lytton

Saguin

Peters

FlewellerFPP

Flatonia

Hallettsville

So. Lane City

Columba

Edna

Carbia

Kingsville

Pleasantion

Kennedy

Skyline

HondoUvalde

Asherton

Del Reo Brackettville

Eagle Pass

Zapata

Bruni

Falfurrias

Edinburg

Stratton

DOW

T.H. WHARTONGREENSBAYOU

W.A. PARISH

SOMMERS

SAN ANTONIO

PEARSALL

SAN MIGUEL

LAREDO

FALCON DAMRaymondville

BARNEYDAVIS

LON C. HILL NUECESBAY

JOSLIN

RAYBURN

VICTORIA

COLETO

GIDEON

STP

VALASCOBlessing

Angleton

Zorn

LA PALMAJ.L. BATES

Coleto Creek

CPSLCRA

Center Point

AEP-TNC

Del Rio

Pawnee

Eagle Pass

PiedrasNegras

HERCULESPOT

LA AMISTAD

NAVA

( 2 )

N. ROSITA

RIO ESCONDIDO

CARBON II

NUEVOLAREDO

MATAMOROSRIOBRAVO

FALCON

TORREONSUR

LAMPAZOS

V. GARCIA

HUINALA

PVMONTERREY

REYNOSA

CD. VICTORIA

SALTILLO

ALTAMIRA

ESCOBEDO

PLAZA

( 2 ) ( 2 )

TEC

MONCLOVA

MONTE MORELOS

FRONTERA

AMISTAD

(2)(3)

ANDALUCIAGOMEZ

PALACIO

LERDO

PRESAFALCON

( 2 )( 2 ) ( 2 )

( 2 )

( 2 )LAUROVILLARANAHUAC

AEROPUERTO

( 2 )( 2 )

(3)

36 MWHVDC

AEP-TCC

CFE

Gulf of Mexico

CFEArea 1 Matamoros-BrownsvilleArea 2 Reynosa – McAllenArea 3 Nuevo Laredo – LaredoArea 4 Piedras Negras – Eagle PassArea 5 Presa Falcon – FalconArea 6 Ojinaga - Presidio

Area 1

Area 2Area 5

Area 3

Area 4

CAMARGOHERCULES

SANTIAGO

FCO.VILLAAVALOS

CUAUHTEMOC

CHIHUAHUA

Area 6

230 kV

138/115 kV69 kVGeneration

Substation

345/400 kV

United States

Mexico

PresidioOjinaga

AlamitoCreek

Marfa Alpine

( 2 )

PTO. ALTAMIRA

S. Lane City

Austrop

KendallSan Marcos

Lytton

Saguin

Peters

FlewellerFPP

Flatonia

Hallettsville

So. Lane City

Columba

Edna

Carbia

Kingsville

Pleasantion

Kennedy

Skyline

HondoUvalde

Asherton

Del Reo Brackettville

Eagle Pass

Zapata

Bruni

Falfurrias

Edinburg

Stratton

DOW

T.H. WHARTONGREENSBAYOU

W.A. PARISH

SOMMERS

SAN ANTONIO

PEARSALL

SAN MIGUEL

LAREDO

FALCON DAMRaymondville

BARNEYDAVIS

LON C. HILL NUECESBAY

JOSLIN

RAYBURN

VICTORIA

COLETO

GIDEON

STP

VALASCOBlessing

Angleton

Zorn

LA PALMAJ.L. BATES

Coleto Creek

CPSLCRA

Center Point

AEP-TNC

Del Rio

Pawnee

Eagle Pass

PiedrasNegras

HERCULESPOT

LA AMISTAD

NAVA

( 2 )

N. ROSITA

RIO ESCONDIDO

CARBON II

NUEVOLAREDO

MATAMOROSRIOBRAVO

FALCON

TORREONSUR

LAMPAZOS

V. GARCIA

HUINALA

PVMONTERREY

REYNOSA

CD. VICTORIA

SALTILLO

ALTAMIRA

ESCOBEDO

PLAZA

( 2 ) ( 2 )

TEC

MONCLOVA

MONTE MORELOS

FRONTERA

AMISTAD

(2)(3)

ANDALUCIAGOMEZ

PALACIO

LERDO

PRESAFALCON

( 2 )( 2 ) ( 2 )

( 2 )

( 2 )LAUROVILLARANAHUAC

AEROPUERTO

( 2 )( 2 )

(3)

36 MWHVDC

AEP-TCC

CFE

Gulf of Mexico

CFEArea 1 Matamoros-BrownsvilleArea 2 Reynosa – McAllenArea 3 Nuevo Laredo – LaredoArea 4 Piedras Negras – Eagle PassArea 5 Presa Falcon – FalconArea 6 Ojinaga - Presidio

Area 1

Area 2Area 5

Area 3

Area 4

CAMARGOHERCULES

SANTIAGO

FCO.VILLAAVALOS

CUAUHTEMOC

CHIHUAHUA

Area 6

230 kV

138/115 kV69 kVGeneration

Substation

345/400 kV230 kV

138/115 kV69 kVGeneration

Substation

230 kV

138/115 kV69 kVGeneration

Substation

345/400 kV

United States

Mexico

PresidioOjinaga

AlamitoCreek

Marfa Alpine

( 2 )

PTO. ALTAMIRA

Texas - Mexico Border Systems

Sharyland HVDC Project

• 150 MW Back-to-Back HVDC tie expandable to 300 MW

• Classic Technology• Operating at:

• 138 kV AC• +/- 21 kV DC

• In-Service October 2007

Basic Criteria

• The Interconnection must be “open-access”.– By Tariff design, the unit is open to all users.

• The technology must block disturbances from spreading into either system.– The inherent nature of DC technology acts as a firewall to

prevent disturbances from spreading system to system.• It must provide for all of its own Reactive Power

support.– Additional filter capacity (Var support) provides for rapid

injections of power from CFE into ERCOT and vice-versa during periods when peak loads or disturbances require additional support.

Basic Criteria

• It must provide for frequency regulation and maintain voltage at appropriate levels. – The control system can control or follow the frequency.

• Load pick-up and/or the ability for BlackStart in the range of 25 MW to full rated capacity was required.– Not inherent to conventional HVDC. However, BlackStart

capability was achieved with the addition of a bypass circuit.– “Make-Before-Break” capability during restoration of power

Design Issues

Load Flow and Contingency Stability Studies

– Determine power flow levels and system response in various contingency situations

• Loss of lines• Loss of generation

– Dynamic system response• Reactive support• Voltage and current disturbance

CFE-Sharyland2007Maximum Import

ERCOT System

Case 1

Variables IV

Variables V

Case 1: Three-phase-to-ground fault at Aeropuerto 400 kV on line to Villa de García. Fault clearing in 6 cycles.

Generator speed of Rio Bravo unit 3 (RIB-U3)Generator speed of Río Bravo gas turbine (RIB-TG) unit

Generator speed of Rio Bravo III units (RIBIIIG1)

Generator angle of Rio Bravo unit 3 (RIB-U3)Generator angle of Río Bravo gas turbine (RIB-TG) unit

Generator angle Rio Bravo III units (RIBIIIG1)

Design IssuesSubsynchronous Torsional Interaction - SSTI

Determine the effects of vibration due to oscillation on the turbine-generator shafts on the AC Network in the vicinity of the unit.

GeneratorIP-HPTurbineLP

Turbine

RotatingExciter

GSU

HVDCControls

Idc

ω

Ig

αVac

Vg

Design Issues

Additional Issues– Short Circuit Ratio– Determine Harmonic effects– Protection Coordination– BlackStart Sequence Coordination– Over and under voltage Coordination

Regulatory and Permitting

Presidential Permit from the United States Department of Energy• Justification of need• Environmental • Operational Requirements

Certificate of Convenience and Necessity (CCN) from the Public Utility Commission of Texas• Stakeholder discussions• Commercial Policy implications

Regulatory and Permitting

Physical Permits• US Army Corps of Engineer• International Boundary and Water Commission

• Clearance over navigable waters• Hydrology issues• Levee considerations

• Mexican Counterparts• CILA

Regulatory and Permitting

Interconnection Agreement - Sharyland Utilities and Comisión Federal de Electricidad (CFE)

System Support Agreement - Electric Reliability Council of Texas and Comisión Federal de Electricidad (CFE)

ERCOT Requirements - Protocols Revisions and changes to the Operating Guides

FERC Jurisdictional Issues - Declaratory Order

Mutual Benefits

• Enhances system reliability• Provides access to

additional generation resources

• Provides access to new wholesale markets

• Reduces environmental impact through avoidance or deferral of new generating facilities

• Reduced electric rates to consumers in both Countries.

Why a DC Tie now?

• Studies emphasize need for interconnections along the Texas and Mexican Border - specifically pointing out availability in Brownsville, Laredo and McAllen Areas.

• Infrastructure needed to support growth in the Rio Grande Valley – Joint Planning– More efficient use of existing infrastructure

• A DC Tie will remain useful even as economic conditions change. It is not a stranded investment.

Mark E. Caskey, P.E.Sharyland Utilities, L.P.

4403 W. Military Highway, Suite 700McAllen, Texas 78503

(956) 687-5600mcaskey@su-power.com

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