Resistive and Inductive Fault Current Limiters: Kinetics ...

TECHNOLOGYCENTRE Bruker HTS GmbHBruker Advanced SuperconBraunschweig; May 13, 2009 / Areva T&D+Bruker HTS

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Resistive and Inductive Fault Current Limiters:Kinetics of Quenching and Recovery

Inductive and Resistive HTS Fault Current Limiters: Prototyping, Testing, Comparing

F. Mumford, Areva T&D A. Usoskin, Bruker HTS

AREVA T&D Research & Technology Centre

Stafford, UK

Bruker HTS GmbH

Hanau, Germany


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SuperconductingFault Current Limiter

forElectrical Power System

Protection

Part 1

Resistive and Inductive Fault Current Limiters:

Kinetics of Quenching and Recovery

Part 2


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SuperconductingFault Current Limiter

forElectrical Power System

Protection

Part 1


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�Growing electricity demand in industrialised countries

� Evolution of 2.5% average per year

�Why such an evolution in electricity demand?

� Cities are becoming increasingly populated

� New gadgets

� Electric transportation

� Better life style

� Etc.

Future needs for Electrical Power

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High stresses result in higher probability of fault s

In the near future, networks may reach or exceed their short-circuit limits!

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Fault Current Limiters(FCL)

are urgently needed

� Increase of fault levels beyond existing circuit-breaker capacities

�Fault levels increasing before circuit-breaker opens (first peak)

Many networks may soon reach or Exceed their Short-Circuit Limits!

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Before and after a fault current…

�What are the causes of faults?

� Severe weather

� Errant tree branches

� Wandering squirrels

� Equipment failures

� Metal poles…

Consequences of a major a fault …… .

�What are the consequences?

� Interruption of customer service

� Increase costs

� Loss of income…

Consequences of a major a fault …… .Consequences of a major a fault …… .

�What are the consequences?

� Interruption of customer service

� Increase costs

� Loss of income…

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Aftermath of a major Short-Circuit FaultTransformer Damage

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Aftermath of a major Short-Circuit FaultTransformer Damage

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The network system reaction

�Present network systems are designed to tolerate hi gh currents for several cycles

�Faults interrupted within:

� 100 msec ( [[[[ 100 kV system)

� 60 msec (>100 kV system)

But, the system fault levels are increasing !But, the system fault levels are increasing !

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The main benefits of the insertion of a FCL …

�Improve power quality

�Avoid:

�Over-dimensioning of equipment

�High investments

�Replacing existing equipments that have a low ratin g

compared to the high rating required

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The Optimum Solution: Superconducting Fault Current Limiter

�Properties

�Self activating

�Fail safe

�Low maintenance

�High impedance in fault operation

�Low impedance in normal operation

�Limits fault current before first peak

�Tolerant to a 5 cycle fault current limiting (100 msec.)

�Operational before circuit-breaker re-closes

�Environmentally friendly (liquid nitrogen cooling,77K)

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Three Most Common types of FCL

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Resistive FCL with protective shunt

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FCL with saturated iron

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Inductive Shielded FCL in a network system

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How do Superconducting FCLs work� When operated below critical parameters:

� Tc (temperature )

� Ic (current )

� Hc (magnetic field )

�Superconductors have virtually zero resistance

� When operated above Tc, Ic, Hc, normal state resistance is restored

� The inherent ability to “switch”from virtually zero resistance to a finite value when Ic is exceeded can be used to limit short-circuit fault currents

� This switching property is utilised in the inductive shielded type FCL

� SFCL

Tc

Ic

Hc

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What is an SFCL?

�The SFCL is a transformer with:

�A shorted secondary superconducting winding

�A copper primary winding connected in series with a network line

�In normal network operation, magnetic flux is excluded from the transformer iron core

�Low impedance is seen by the system

�In a fault limiting scenario Ic for the superconductor is exceeded and flux enters the core

�Large impedance is seen by the system

Fault current is limited & the system protectedFault current is limited & the system protected

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Fault Current Limiting with an SFCL

-20000

-10000

0

10000

20000

30000

40000

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

Prospective Fault Current

Limited Fault Current

Fault Onset

Normal

operation

Cur

rent

(A

)

Time (s)

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Inductive Shielded type SFCL

Primary winding

Cryostat

Superconducting Cylinders

Laminated Iron Core

�Construction

�Transformer device with:

� Copper primary winding

� Superconducting “shorted”secondary winding.

�Primary winding is in series with the line to be protected.

SFCL has the potential to meet all FCL objectivesSFCL has the potential to meet all FCL objectives

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Safety assured with the SFCL

Bruker HTS GmbH

Resistive and Inductive Fault Current Limiters: Kinetics of Quenching and Recovery

Part 2

TECHNOLOGYCENTRE

Bruker HTS GmbH

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FCL demonstrators

- Constructions

- CC Tapes

- FCL Assembling

- Measurements

- Results and further steps

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Processing route for YBCO coated conductor

deep polishing

US cleaning

ABAD YSZ buffer

HR-PLD

CeO2

HR-PLD

YBCO

PVD

Ag or Au

Annealing

Cu platin

g

150µm

Vacuum, mbar 10-5 10-1 10-1 10-5

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Shunt layer in SFCL

0

1

2

3

0 2 4Shunt thickness (µm)

Ele

ctric

al fi

eld

(V/c

m)

1

2

3

dA

dP

dE ⋅= ρ ρ is resistivity of the shunt metal,

d is a shunt thickness and dP/dA is a surface density of power dissipation.

200 W/cm2

50 W/cm2

100 W/cm2

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Inductive shielded and resistive SFCL

SUPERPOLI FCL-5.5-50 module based on YBCO-coated stainless steel tubes and Au shunt layer.

Nominal (non-limited) current 2 500 A (ampl.)Nominal power losses ~ 0.1 WFault current, max. 50 000 A (ampl.)Peak power at fault current: 150 000 W

∅ 55 mm

500 mm

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Bruker HTS GmbH

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Inductive shielded FCL: Components

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Inductive shielded FCL: Components

TECHNOLOGYCENTRE

Bruker HTS GmbH

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R(I) curves

0

2

4

6

0 2 4 6Current (kA)

Res

ista

nce

(mO

hms)

1 2 3

IS-SFCL

IS-SFCL

R-SFCL

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Inductive SFCL: I(V) curves

0

200

400

600

800

1000

0 20 40 60

Voltage (V)

Cur

rent

(A

)

0,2

1

0,6

2

3

A B C D

0,4

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Bruker HTS GmbH

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Cu losses are subtracted

Test SU240b cu100trns, 11x7CC-mod

0

1000

2000

3000

4000

5000

6000

7000

0 10 20 30 40 50 60 70 80 90 100

voltage 1, V

curr

ent 2

, pro

sp. c

urre

nt 1

, A

3800A Oscill.

Z1(at 3000A)=0.25 V/30 A= 8.3 mOhms => ∆U = 0.8 V at 100A

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Kinetics of quench and recovery: inductive SFC

-2

0.6ms

<0.2ms

20 40 60 80 0 0

1

2

-1

Cur

rent

(kA

)

Time (ms)

Kinetics of quench and recovery in SFCL with a shielding module exhibiting 0.9 kA critical current.

Current versus time at quench event with duration of 31 ms. Prospective current of 30 kA (peak value) is limited to 1.2 kA (second peak).

TECHNOLOGYCENTRE

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I

UFCL

1ms

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Current versus time at quench event with duration of 90 ms.

Prospective current of 20 kA (peak value) is limited to 5 kA (second peak).

During quench current in primary winding corresponds to 40-50 A.

Cur

rent

(kA

)

Time (ms)

0 50 100 200 150 250

0

2

4

6

-2

-4

-6

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Shunt layer in SFCL: R-SFCL

00

5 time [ms]15

2

4

-2

-4

current [kA]

0.5 ms

fault current

limitedcurrent

nominal current

10 20

TECHNOLOGYCENTRE

Bruker HTS GmbH

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Summary

A. There is no difference in performance of inductive SFCL andresistive SFCL

B. Nevertheless, the inductive SFCL

- has favorable functionality at HV

- exhibits less cooling losses (no current leads in the cryostat)

- should have similar dimensions and weight (!)

C. Low loss (Z<0.015 Ohm) in the nominal regime aredemonstrated in 100kVA

TECHNOLOGYCENTRE

Bruker HTS GmbH

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SFCL Demonstrator

EHTS Design for a 10kV Demonstrator

TECHNOLOGYCENTRE


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Thank you for your attention

Resistive and Inductive Fault Current Limiters: Kinetics ...

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