Superconducting Fault Current Limiters

kitefleaUrban and Civil

Nov 15, 2013 (3 years and 8 months ago)

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Current Solutions

for Future Networks

Chris Waller

CRYOGENIC CLUSTER DAY PROGRAMME SEP 28 2011

Superconducting Fault Current Limiters

The John Vandore Challenge


Squeeze my normal 110 slides which takes an hour
into 15 minutes!



So here goes.

Current Solutions

for Future Networks

The fault current challenge
-

1

Current Solutions

for Future Networks

G

Generator

Circuit breaker

Load

Copper line

G

Short circuit:

Fault Current
unrestricted
by load

G

Circuit breaker
interrupts fault
current

The fault current challenge
-

2

Current Solutions

for Future Networks

Image © Palm Harbor Fire Department

The fault current challenge


3

Current Solutions

for Future Networks

G

G

G

G

G

G

Climbing
fault
current

The fault current challenge
-

4

Current Solutions

for Future Networks

G

G

Split the
network

Upgrade Circuit
Breakers


Install
Reactors



Install high resistance
Transformers


The fault current challenge
-

5

Current Solutions

for Future Networks

G

G

Circuit breaker
can operate
safely


G

G

Instant rise in
resistance
limits fault
current


G

G

Zero resistance


The fault current challenge
-

6

Current Solutions

for Future Networks

132kV

fault prone
network

Rural
Semi
-
Urban
Urban

Sensitive

Load

Too
Much
Load

Plenty of
capacity

132kV

33kV

11kV

11kV

11kV

33kV

40M
W

Wind
farm

11kV

11kV

Load

sharing

Security

of supply

Generator

Generator

Generator

Key characteristics of Fault Current Limiters based on
superconducting materials



Under normal operation a fault current limiter inserts
negligible impedance into the network



When a fault occurs the limiter‘s impedance rises rapidly,
reducing the current flowing through it



The fault current challenge


eureka

Some types of
Superconducting

Fault Current Limiters

Resistive

Shielded core

Pre
-
saturated

Core

Induced current in the Superconducting
tube shields the iron core until
excessive current causes quench.

Superconductor quenches under
excessive fault current reverting to a
normal conductor, inserting resistance.

Iron core driven into saturation by
superconducting DC winding. Fault
current opposes the saturation and
increased impedance switched into the
circuit.

DC

Fault Current Limitation

Early Projects

Current Solutions

for Future Networks



Project 1 & 2

Resistive Type utilising Bulk
BSCCO

Nexans

Superconductors




Project 3 & 4

Pre Saturated Core Type utilising
BSCCO Tape

Zenergy

Power


Early Projects

Current Solutions

for Future Networks

11kV /
100A

2010

2011

2012

2009

11kV/400A

11kV/1250A

33kV / 800A

11kV/ 1250A

MgB2 demonstrator

operation

2013

1
st

in commercial network

B (magnetic field)

J (current density)

T (Temperature)

Superconducting

properties

Normal

conducting

properties

Normal

conducting

properties

Normal

conducting

properties

Superconductors remain in the
superconducting state as long as the
current, temperature and flux density
remain below the
critical values
.

Critical Characteristics

Resistive Limiters

Resistance

Superconducting
range

Normal
range

Critical
Value

Low

High

Equivalent circuit

Superconducting Characteristics


Resistive Fault Current Limiters


Resistive Limiters

fault current

limited fault current

Up to 90% clamping

Clamps within 1.5 ms

Removes DC component

Resistive FCL


Limiting Behaviour



ETI Commissioned Project secured in June 2011 to develop a MgB2 type
SFCL with a view to targeting the future mass market.


The prototype will be installed
i
n substation on Western Power
Distribution’s network in Summer 2013.


Key parameters










Nominal operational voltage and frequency:


11kV, 50Hz



Maximum normal load current:




1250A





Prospective
fault current


50kA
pk
(20kA
rms
) reduced to less than 7kA
pk




Resistive MgB
2

SFCL Development

HV
Bushings

Helium
Compressors


Heat
Exchanger

Current Limiting
Modules

Resistive FCL


Key Components



Using the quench: Even quenching, no hot spots, material homogeneity




Wire heating:


Removal of the heat (0.96MJ in 120ms)




reset within 3 minute




Low thermal losses

Current leads




AC losses in superconductor/sheath




Induced losses in cooling systems




Enclosed volume & thermal radiation


Resistive MgB
2

SFCL
-

Challenges


Customer driven issues


Fail safe





No maintenance.





Low carbon footprint





Competitive with alternative options





Low noise.



Suppliers:



Limited MgB
2

wire suppliers. All





interested in MRI as mass market.










Cryogenic components suppliers needed.





This is why we are here!




Resistive MgB
2

SFCL
-

Challenges

Current Solutions

for Future Networks

Thank you !


Superconducting Fault Current Limiters

are a bottleneck component in the rise of Clean Technologies
and Smart Grids

and critical to meet Low Carbon targets