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Southwire Entergy HTS Cable Project

David KnollProject Manager

HTS Cable Systems

Eigth Annual EPRI Superconductivity Conference

Oak Ridge, TN

November 12-13, 2008

Erik Guillot

Project ManagerTransmission EMCC

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Project Partners

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Project Specs

Cable Design HTS TriaxTM - Superconducting

Length 1760 meters (1.1 miles)

Voltage 13.8 kV

Load 48 MVA

Cooling Single Point, Closed Cycle

Splices 2 (Cable Sections = 3)

In-Service Date 1Q2011

Cooling Plant13.8 kV, 2.0 kA (48 MVA) Triax HTS Cable

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Project Location

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Cable Route

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Project Overview:Replace Copper HV Transmission with HTS MV Distribution

Problem:

Saturated 13 kV distribution anticipate high load growth

230/13 subs to north & south of area - Need new sub at mid-point

Challenges:

OH RoW for 230 or 13 kV very difficult or impossible

Small footprint available for new substation

230 kV solution: placing transformer in dense residential area.

13 kV conventional: Voltage drop, power quality

Solution:

13 kV HTS cable to transmit 48 MVA into small footprint station.

1.1 mile HTS cable that meets load growth needs.

Leverage existing transformer capacity No new transformers needed

Single point cooling station.

13 kV HTS replaces 230 kV underground. Cost effective with DOE support.

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Southwire - HTS TriaxTM 2000A Cable

Cryostat

Former Phase 1 HTS

Phase 2 HTS

Dielectric

Phase 3 HTS

Copper Neutral

LN

LN

HTS TriaxTMAdvantage vs Competition:

1. HTS tape usage = substantially cheaper

2. Single Cable = simplified mfg & installation

3. Smaller cold surface area = lower cooling & operating cost

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Southwire Triax Cable Termination

3 Phase Connections

Neutral Connection

- Provides transition from

superconducting materials to

copper materials.- Thermal transition from 200 C to

ambient temperature

- Controls electrical stresses.

- Provides input and/or output

location for LN coolant.- Provisions made for temperature

and pressure measurements and

monitoring.

- Electrical connections to utility

made by means of industry

standard NEMA pad.

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Cable Installation

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On Going Effort - HTS Tape Options

1G BSCCO vs 2G YBCO

Mechanical testing Compatibility with cabling process

Electrical Properties Ic, n-Value, AC Loss

Magnetic Properties Piece Lengths

Wire availability

Per meter costs

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On Going Effort Cable Configuration

1G 2GComposite 1

1G

Segment 1 Segment 2 Segment 3 Spare

1G 2G2G 1G

1G 1G

2G2G

1G

1G 1G

2G 2G

Composite 2

All 1G

All 2G

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On Going Thermal / Hydraulic Analysis

Former, RT

Heater - Qknown

Insulation RT

Heater - Qknown

Insulation RT

Heater - Qknown

Insulation RT

Cryostat WallLN2

LN2

Temp

Sensors

THERMAL MODEL

Former, RT

HTS AC Loss, RT

Insulation RT

HTS AC Loss, RT

Insulation RT

HTS AC Loss, RT

Insulation RT

Cryostat WallLN2

LN2

CABLE ASSEMBLY

66

67

68

69

70

71

72

73

74

0 500 1000 1500 2000

L [m]

T

[K]

Annulus

Former

Tmax

Ph1

Ph2Ph3

Neutral

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On Going Effort Cryogenic System Design

~ 10kW cooling required

Closed loop cooling system

Cryocooler Options

Pulse Tube

Sterling Cycle Brayton Cycle

RFPs out after AC Loss study

System supplier will performdetailed system design

Heat Exchanger

Closed Cycle

n

HTS Cable

Back-up

Open Cycle

21

Cryocooler Bank

LN2

Tank

Sub-Cooled LN2

Counter Flow Cooling

Out = thru former

In = thru annulus

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Previous Experience AEP, Columbus, OH

AEP-Bixby

200 meters8/2006 to present

13.2 kV, 3.0 kA,

Triax Cable

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5 DAY Bixby Peak Load August 2007

Peak Load = 2,715 A

0

500

1000

1500

2000

2500

3000

0:00:00 0:00:00 0:00:00 0:00:00 0:00:00

Curre

nt(Amps)

Phase 1

Phase 2

Phase 3

Neutral

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AEP Data Fault Currents

07/11/2008

01:24:20.500

07/11/2008

01:24:27.425

No measurable thermal response in

HTS cable or terminations.

Transient event: I 3.0 kA (2,121 A-rms)

74 total events

39 events with >4,242 A-pk (3,000 A-rms)

19 events with >5,657 A-pk (4,000 A-rms)

13 events with >7,071 A-pk (5,000 A-rms)

7 events with >14,142 A-pk (10,000 A-rms)

Highest current = 17,765 Apk (222

milliseconds)

Longest duration = 1.785 seconds (5209Apk, 3683 Arms)

HTS cable never taken out of service.