24 overhead lines and cables

7/28/2019 24 Overhead Lines and Cables

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Room 6.2

.Wednesday, 14th September(11.00 - 12.45)

Rpt: Marco Marelli

241 HV submarine cables for renewable offshore energy - G. Dell Anna,P. Maioli, A. Micheletti, E. Zaccone

242 Past experience and future trends with compact lines to solve theright-of-way issue - K.O. Papailiou, F. Schmuck

-

AC/DC hybrid line with regard to audible noise - U. Straumann, C.M.Franck

au curren m ng power ca es or m ga on o au eve s ntightly interconnected systems - K. Howells, D. Folts, J. Mccall, J. Maguire


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HV Submarine Cables For

Renewable Offshore Energy

Gaia Dell Anna, Prysmian Power Link,

Andrea Micheletti, Prysmian Power Link,Ernesto Zaccone, Prysmian Power Link,

Paolo Maioli, Prysmian S.p.A.

CIGRE Bologna 2011

, ,


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The Offshore power generation

The recent years have shown a large

generation especially in the European northern

Sea areas

The location of these large off shore wind farms

and requested the adoption of submarine cableconnections that are the unique possiblesolution

epen ng on e s ance an e power o etransmitted both ad hoc HVAC and/or HVDCsolutions have been ado ted.

CIGRE Bologna 2011


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Ambitious European Projects

Moreover, a so-called" "is proposed for integratingoffshore wind ener in theNorth and Baltic Seas into afuture EU internal electricity

market.

SCOTLAND is also

mentioned as a key region

various renewable energysources accountin for u to

CIGRE Bologna 2011

68 GW by 2050.


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Characteristics of HVAC Cables

Cable structure description

Armoring Losses IEC 60287vs laboratory experience

capabili ty test experience

Mechanical performance

CIGRE Bologna 2011


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Typical HVAC submarine Cable

1) Copper conductors

3) XLPE extruded insulation

4) Semiconducting insulation screen

5) Swelling tapes

6) Lead alloy sheath

o yet y ene ac et

8) Polypropylene fillers

9 Pol ro lene bindin

10) Polypropylene string bedding

11) Galvanized steel wire armour

12) Polypropylene string serving

13) Fiber optical unit

CIGRE Bologna 2011


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Typical HVDC submarine Cable

1) Conductor

3) Extruded insulation

4) Semiconducting insulation screen

and Swelling tapes

5) Lead alloy sheath

6) Polyethylene jacket7) Polypropylene string bedding

8) Galvanized steel wire armour

9) Polypropylene string serving

Typical diameter: 90 to 120 mm

CIGRE Bologna 2011

THE VSC COVERSION TECHNOLOGY;TRADITIONAL MI CABLES ARE ALSO AVAILABLE IF

NECESSARY


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Cable testing

Magnetic field measurement

Very low EMF emissions

Phase resistance of HV tricore cable.-

4,5E-05

, -

/m

]

3,5E-05

4,0E-05

e

resistance

[Oh Pb closed wi th armouring

Pb closed no armouringMagnetic field measurement

3,0E-05

Phas


CIGRE Bologna 2011

, -

0 200 400 600 800 1000 1200 1400 1600 1800

Current [A]


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Cable testing

Mechanical testing in laboratory

Magnetic field of 132 kV tricore cable: current 400 A.

1000,00

measured wi th armourning

computed parallel

10,00

100,00

ld[microTesla]

computed helix

Magnetic field measurement

0,10

,

Magneticfie


CIGRE Bologna 2011

,

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 2,8 3,0

Distance from cable axis [m]


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HVAC or HVDC ?

HVAC is more practical and simple, but may have some limitation in the lengthand transmissible power.

HVDC require the conversion stations; the VSC technology converters allow the

installation on offshore platforms and advantages in the management andregulation of the transmissible load.

The adoption of the solution isevaluated case by case, on atechnical and economicalevaluation.

As a rule of thumb the ran e ofconvenience of HVAC Vs HVDC can

be summarized by this graph.

CIGRE Bologna 2011


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Greater Gabbard

One of the largest offshore wind farms

Customer:

InnerGabbard

Fluor Ltd

Project ownership:

site

NPower

Project Scope:

Main offshore

section 3 x 132kV

Cables 800mm2

(each 47km)

Cable to connect 2platforms1 x 132kV Cable800mm2(19km)

504 MW with 140 wind turbinegenerators

Gallopersite

160 km 3 core 800 mm2 CuXLPE Pb SWA Submarine cable

CIGRE Bologna 2011


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Typical Layout of an Offshore Wind Farm

Transmission Grid

HV station

HVAC or HVDC cableMV Cables 20 or 30 kV

contribution

-transformer platform

CIGRE Bologna 2011


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BorWin 2

400 km cable, 300 kV, 800MW HVDCGrid Connection of offshore wind farms

Route Length:

76.4 km HVDC Onshore Route (150 km cable)

123.4 km HVDC Offshore Route (246.8 km cable)

2x11.4 km & 2x28 km HVAC Offshore Route (79.8 km cable)

ower a ng o age eve :

800 MW @ 300 kV

155 kV AC

CIGRE Bologna 2011


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HelWin1

HelWin1 260 km HVDC cable, 250 kV, 576 MW

Route Length:


85 km HVDC Offshore Route (170 km cable)

x . m s ore ou e . m ca e

Options: 2 x 7.6 km HVAC Route

Power Rating / DC Voltage Level:

576 MW @ 250 kV

CIGRE Bologna 2011


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SylWin1 & HelWin2

SylWin1 410 km cable

320 kV, 900 MW HVDC

HelWin2 260 km cable

320 kV, 690 MW HVDC

Route Length:


159 km HVDC Offshore Route (318 km cable)

Route Length:

46 km HVDC Onshore Route (92 km cable) 85 km HVDC Offshore Route (170 km cable)

x . m s ore ou e . m ca e Options: 2 x 40km & 2 x 35km HVAC Route


900 MW @ 320 kV

2x8 km HVAC Offshore Route (16 km cable)


690 MW @ 320 kV

CIGRE Bologna 2011


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Alpha Ventus

First Major German Offshore Wind farm

E.ON Netz Offshore

Cable scope:66 km 110 kV 3 core 240 mm2 CuXLPE Pb SWA cable and accessories

CIGRE Bologna 2011


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Thanet Project

Customer:Thanet Offshore Wind Ltd

Cables:55 km 132 KV 3 Core 630/1000 mm2

72 km 33 KV 3 Core 95 300 400 mm2

140000

160000

180000

G1F1E1

D1

C1

B1

Line 8

Line 7

80000

100000

120000

A1

G11

Line 1

Line 2

Line 3

Line 10

Line 9

20000

40000

60000

A12 D17C15B14

E17

F14Line 4

Line 5

Line 6

CIGRE Bologna 2011

0

0 100000 200000 300000 400000 500000 600000 700000


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an you or your a en on

CIGRE Bologna 2011


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Cigr 2011 Bologna Symposium The Electric Power System of the Future

Paper 242

RIGHTOF

WAY

ISSUE

by

.

.

.

PFISTERERHOLDINGAG PFISTERERSEFAGAG

. . . .

UniversityofBologna,FacultyofEngineering September13th 15th,2011


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CompactionLine

means

50m 9.6m

UniversityofBologna,FacultyofEngineering September13th 15th,2011January2006IdeaforCompaction


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easons

or

ompact

ne

rrangements

Reduction of total line costs.

Right of Way (ROW).

Redundancy due to bracing longrod.

Reduction of influence of the electroma netic field.

aesthetic-visual impact, pleasing to public.

in service since the 80ies. e.g. nUSA,Ita yan Greece



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Prosan

Cons

o

Compact

Lines

Pros

Cost savings for tower and foundation construction.

Aesthetically pleasing.

Reduced EMV on ground level. Higher power transfer capacity because of lower surge

impedance.

Fail-safe redundancy because of the use of twoinsulators in the case of braced line posts.



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Prosan

Cons

o

Compact

Lines

Cons

Increased corona level because of shorter distances

Shorter span lengths (if no phase spacers are used)

More demanding conductor stringing process Maintenance issues, especially live-line-work

Mechanical stability problems.



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e

w ssexper ence


Ci 2011 B l S i Th El i P S f h F


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e

w ssexper ence

420kV

com act

420kV

traditional

Steellatticetowerof125kV19m

lineandSwisscompacttower

for400kV/132kVlineaswellas125kV

8.6m

9m



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Real-life a earance of Profiles o timized for mechanical

unique compact tower strength versus material use

Ci 2011 B l S i Th El t i P S t f th F t


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ons era ons compactconventional

UniversityofBologna,FacultyofEngineering September13th 15th,2011Simulation

for

current

of

1000

A

and

at

1

meter

above

ground

Cigr 2011 Bologna Symposium The Electric Power Systemof the Future


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xamp eo

w ss

tra t on

van age e erer




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T eSwiss

experience

Combinationofinnovativeconcepts

CarbonFiberReinforcement

+lowerweight

+ no corossion




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So utionso

Con uctor

Attac ment

Sus ended

Multifunctional

solutionwitha

plasticbumper

rigidattachmentrigidattachment




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equ remen s

or

es ngMechanicalDesign

FEMSimulation,especiall FullScaleTesting

ForceProbe

ResultingForce

Angle




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equ remen s

or

es ngElectricalDesign

FEM(BEM)Simulation,especiall FullScaleTesting

PhaseB PhaseB

PhaseC PhaseA




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Summary

-solutions to solve right-of-way constraints and to provide

a technical solution to reduce electromagnetic field onground.

They are a very attractive solution when upgrading an

existing transmission system, e. g. from (123 kV as inCH) 245 kV to 420 kV.

They have been introduced for voltage levels up to 420kV so far, further developments for 525 kV and if possible

.

A full scale mechanical and electrical testing is highly-

UniversityofBologna,FacultyofEngineering September13th 15th,2011.


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g g y p y

esponseto

uest ons

+

solution in comparison to cable or gas-insulated line

(GIL). Due to the reduced mechanical load to the pole ortower, very aesthetic solutions can be introduced.

It is recognized to be the only solution when upgrading an

existing transmission system, e. g. from (123 kV as inCH) 245 kV to 420 kV.

The existing standard IEC 61952 provides general rulesfor composite post insulators, however the solutions are

-conditions and locally applicable laws.



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Discussion of Converting a Double-Circuit AC Overhead

Line to an AC/DC Hybrid Line with Regard to Audible Noise

. , . .High Voltage Laboratory, ETH Zrich

Cigr-Symposium, Bologna, September 13-15, 2011

Cigr-Symposium, Bologna, September 13-15, 2011 Slide 2


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Problem

RenewablesCapacity increase of transmission

Contents of the presentation

s nee e

No new transmission corridors

1)Interaction Between Circuits in aHybrid Line

alternatives to increase capacitieswithin existing ROWs e. .: convertin AC to DC

Investigated Conversions

3)Audible Noise Characteristics of

Existing lines

s

4)Tower Geometries, CalculationMethods

(limiting land use):multi-circuit lines

5)Calculation Results

lines

U. Straumann and C.M. Franck



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1. Interaction Between Circuits in a Hybrid Line

Coupling between AC/DCsurface gradients

capacitive and magnetic coupling (AC-current in the DC-poles) ion current from coronating DC- pole collected by AC phases (DC--

Technical consequence

overvoltages of the DC circuit is increased in hybrid environmentunknown consequence on requirements on insulators in a hybrid




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2. Investigated Conversion

Original line400 kV AC double circuit line

Conductors and their thermalratings

Conversion

Replacing one circuit with a500 kV DC circuit

Transmission capacity

1)Corridor: 160 %


2)Single circuit: 220 %



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3. Audible Noise Characteristics of OHLs

Corona leads toIon currents

DCOnly broadband crackling &

a o n er erenceLosses

Audible noises (AN)

ss ng no seStrongest in dry weather

AC

Broadband and tonal noise (2f)DC vs. AC

Example (EPRI)

tonall

crackling

ise

lev

100 HzNo

~ (1-10) kHz

A-wei htin


Frequency [HVDC Transmission Line Reference Book]



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4. Tower Geometries, Calculation Methods

Geometries LiteratureDC ions do not affect the AC

corona significantlyAC and DC corona may be

affected by superimposed fields,but: Emission may be calculatedby combining the formulas forure AC- and DC-lines

Tonal emission is notcommented

Calculation of audible noise

Formulas from EPRI

Ground wire: 22.4 mmAC-conductor: 27.0 mm

DC noise: HVDC TransmissionLine Reference Book

AC: Transmission Line


-con uc or: . mm Reference Book


5 C l l ti R lt


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5. Calculation Results

HybridOriginal (2 x AC 400 kV) fair (DC)

fair rev. DC

40[d

B(A)]

[d

B(A)]

40

foul weather (AC)

3

35

velL

eq

circuit 1 velL

eq

30

35

- -

25noise

le circuit 2

totalnoisel

25

-100 -50 0 50 100

lateral distance from line axis [m] lateral distance from line axis [m]

AC AC DCAC



C l i


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Conclusion

1) Increase of transmission capacity by the investigated conversion isquite considerable

2) Even though a larger coupling between the AC and DC circuits may

be disadvanta eous in some technical res ects intermixin the ACphases and DC poles on both sides of the tower reduces the surfacegradients and the AN levels in the investigated examples.

3) Polarity reversal may be accompanied by a remarkable change of DCAN levels.

Outlook

Quantification of space charges (ion flow fields):determining electric fields


evoking the DC-current in the AC-phases



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2 Origin of the Audible Noises


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2. Origin of the Audible Noises

PD-patternCorona-discharge

roa an omponen ,

on uc or:ESurface: 20.9 kVpeak/cm

Rain: 8 mm/h

conductor

rotrusion(water drop) 20

]

Strong pulsative dischargesoccur at the ositivel stressed

10itude

[n

electrode

Ampl

AC: Only positive half-waveDC: Only positive pole

0 180 360Phase []



4 Tower geometries calculation methods


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4. Tower geometries, calculation methods

Geometries LiteratureDC ions do not affect the AC

corona significantlyAC and DC corona is affected by

the superimposed fields Emission may be calculated bycombining the formulas forure AC- and DC-lines

Tonal emission is notcommented

Calculation of audible noise

Formulas from EPRI

Ground wire: 22.4 mmAC-conductor: 27.0 mm

DC noise: HVDC TransmissionLine Reference Book

AC: Transmission Line


-con uc or: . mm Reference Book


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Fault Current Limiting Power Cables for Mitigation of FaultLevels in Ti htl Interconnected S stems

Kyle Howells Doug Folts J ack McCall J im MaguireAmerican Superconductor Corporation

CIGRE Symposium

Electric Power System of the Future

Bologna, 13-15 September 2011

Paper 244

1

F lt C t B i


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Fault Current Basics

The maximum

magnitude offault current is a X/R Ratio Typical Systems

for both AC and

DC components

High, 14 Transmission Systems

Industrial Feeders

-

Higher Z reducesfaults at the

,8 14 Large Distribution S/S

Long Feeders

2

expense of

higher losses

,

Th R l f X/R


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The Role of X/R

The maximum The X/R ratio affectsthe duration of the DC

affected by the fault

closing angle

offset

Higher X/R will have

X/R neither helps norhurts in these terms

slower decay

Adding R damps offset

3

S t I d d F lt


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S stem Im edance and Faults

Adding X to system impedance- Lowers overall fault magnitude

- Increases losses

- Increases DC offset decay time

- Negative impact to system stability

Adding only R to system impedance-

- Increases losses

-

- Positive impact to system stability

4

Adding resistance during faults is preferable

S d t F lt C t Li it


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Su erconductor Fault Current Limiters

Superconductor FCLs fall into two categories:

Inductive- These often take the form of a saturable core reactor

field

-Uses superconductors highlynon-linear resistive impedance during

ResistiveBypass Element

quenc o res s ve y m curren an

- To bypass the current into a

arallel b ass elementNon-linear

superconductorelement

5

Key HTS Cable ELECTRICAL Characteristics


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y

Ver hi h ower transfer ca abilit com ared toconventional cables solves many siting problems

ery ow mpe ance re uces oa ng on para e nesand equipment

Minimal magnetic field and elimination of heatsimplifies placement concerns, minimizes right-of-way,an s easy on e env ronmen

O tional HTS cables with fault current mana ementcapabilities eliminate need to upgrade existing equipmentHTS Cables offer unique capabili ties

Power Transfer Equivalency ofSuperconductor Cables


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Superconductor Cables

230kV XLPE

HTS

,Power

- Greatly increased

ower transfer ca acit

69kV XLPE

XLPE

HTS

at any voltage level

Same Power, LowerVoltage

34.5kV

XLPE

XLPE

HTS

HTS- New MV versus HV

Siting Opportuni ty MV Transmission

0 200 400 600 800 1000

.

Power Transfer Capabili ty - 3-phase MVA

ea or ROW sparseenvironments

* No XLPE cable de-rating factors applied.Superconductor rating based on conventional 4000A breaker rating

Superconductor cables provide transmission-level power transfer at medium voltage

Superconductor Example:138 kV 575MW Capacity


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138 kV, 575MW Capacity

200 ft ROW Self contained thermal

envelope No thermal de-ratin

Self contained thermalenvelope No thermal de-ratin

Minimal magnetic field

No parallel line de-rating

Minimal magnetic field

No parallel line de-rating

Longer practicaldistance

Longer practical

distance

4 ft ROW

Superconductor Cables Simplify Placement and Offer New

Options to Siting Lines

Fault Current Limiting Cable Operation


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high resistance layer

Load

zero resistance superconductor layer

Superconductor wire has zero resistance up to

Current

high resistance layer

the critical current

switched high resistance superconductor layer

au

Current

SimplifiedView of

Supercond

uctor wire

Superconductor wire instantly introduces highresistance above the critical current

Immediate limi tation of fault current magnitudes

Insertion of resistance decreases X/R and faultasymmetry

The switching of conductive state is a function of the

superconductor material itself and requires no external control

Current Division in Superconductor FCL CableDurin Quench


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Durin Quench

10

FCL Cable O erational Characteristics


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FCL Cable O erational Characteristics

Fast Res onse- Millisecond

operation

First Peak

RMS Limiting Photo: Courtesy U.S. Dept. of Energy,Oak Ridge National Laboratory- es s ance u s as au

progresses

- Lowers X/R ratio, reducing DC

offset

A Com lex S stem Exam le


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A Com lex S stem Exam le

Paralleling 3 substations-

- Improves load servingcapacity

esu s n g au currencontributions

FCL method re uired

Superconductor Cables Equivalent X/R Cables

17% additionalfault current

re uc on ueto phase shifteffect of

12

cable

Paralleling Urban BusesParalleling Urban Buses

Servin Additional LoadServin Additional Load


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Servin Additional LoadServin Additional Load

HTS Interconnected Substation Loading IncreaseHTS Interconnected Substation Loading Increase apa y; n- r er a

140%

160%

180%

ad

Capabilit y; n -1 Criteria

80%

90%

100%

d

60%

80%

100%

120%

Increas

edLo

Capab

ility

3 XFRMR

4 XFRMR5 XFRMR

30%

40%

50%

60%

70%

ncrease

dLo

Capab

ility

3 XFRMR

4 XFRMR

5 XFRMR

0%

20%

40%

2 3 4 5

Number of Interconnected Substations

%

0%

10%

20%

2 3 4 5

%I

Interconnecting Substations significantly increases load serving capabili ty*

* Theoretical limits

Summar


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Summar

inductance

- 3-10x the normal MVA capacity of XLPE cables

- Simplified right-of-way and placement requirements

- No external EMF

Resistive fault current limiting can be added tosuperconductor cables

- Provides first cycle current limiting

-Lowers X/R, reducing DC offset

- Provides system damping

-

14

24 overhead lines and cables

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