This document discusses fault current limiters using superconductors. It defines fault current and explains the need for limiting fault current due to increasing power demands. It describes the characteristics of an ideal fault current limiter and traditional limiting methods. The document then introduces superconductors as fault current limiters, explaining how their zero resistance below a critical temperature can be utilized. It outlines two main types of superconductor fault current limiters - resistive and inductive shielded core, and describes their operation and applications in limiting fault current.

1. Fault Current Limiters Using
Superconductors
Name – Jaypal
Singh
Roll no. –
104021
Branch –

2. Contents
1.What is fault current?
2.Need for fault current limiter
3.Characteristics of an ideal fault current
limiter
4.Traditional ways to limit fault current
5.Superconductors as fault current limiters
6.Types of SFCL
7.Comparison between different SFCL
8.Advantages of SFCL
9.Conclusion

3. What is fault current?
 Fault current is any abnormal
electric current that flows through
a circuit during the electrical fault
conditions like L-G, L-L-G, L-L-LG, L-L, L-L-L faults.
 Fault current may be several
times larger in magnitude than
the current that normally flows

4. Need for fault current limiter
 Increasing demand
of power and
addition of more
generators, transfor
mers and large
networks causes
higher stress on
power system.
 Higher stresses
results in higher
probability of faults.

5. Characteristics of ideal fault
current limiter
 Have zero impedance throughout
normal operation
 Provides sufficiently large
impedance under fault conditions
 Provides rapid detection and
initiation of limiting action
 Provides immediate recovery of
normal operation after clearing

6. Characteristics cont..

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


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Fully automatic
highly reliable
Light weight
Compact
Low cost
Longer life

7. Traditional ways to limit fault
current
Following methods are used to limit
fault current-:
 Circuit breakers with ultra-high
fault current rating
 High impedance transformers
 Current limiting fuses
 Air core reactors

8. New approach using superconductors
SuperconductorIt is an element, inter-metallic alloy or
compound that will conduct electricity
without offering resistance below a
certain temperature.
Types of superconductors Low temperature
superconductors(LTS)

9. Cont..
LTS are the substances that lose
all resistivity close to 4K, a
temperature attainable only by
liquid helium.
Examples of LTS - Lead and
Mercury
HTS are the substances that
lose all resistance below

10. Superconductor fault current limiter
(SFCL)
Superconductor is used because of
their sharp transition from zero
resistance at normal currents to
finite resistance at higher current
densities(above critical temp).
Parameters for superconductivity Temperature (T)
 Current (I)

11. How do SFCLs work
 when operated below critical
parameters:
• Temperature (Tc)
• current (Ic)
• Magnetic field (Hc)
 Superconductors have virtually
zero resistance
 When operated above

12. Cont..
 The inherent
ability to switch
from virtually
zero resistance
to a finite value
when Ic is
exceeded can be
used to limit
short-

14. Types of Superconductor FCL
 Resistive SFCL
 Inductive Shielded core SFCL

15. Resistive SFCL
 Utilize superconducting material as main
current carrying conductor under normal
grid operation
 To keep it superconducting, it is usually
immersed in a coolant that is chilled by a
refrigerator.
 In case of a fault the inrush of current
and magnetic field take the super
conductor into the transition
region, thereby the increasing resistance

16. Resistive FCL with protective
shunt
superconductor

17. Operation of SFCL
When a fault occurs, the current
increases and causes the
superconductor to quench thereby
increasing its resistance exponentially.

18. Inductive shielded core SFCL
 Device resembles a transformer with the
secondary side shunted by an HTS
element
 An electrical connection is made between
the line and the HTS element through
mutual coupling of AC coils via a magnetic
field

19. Operation of inductive shielded core
SFCL
During a fault, increased current on the
secondary causes the HTS element to
quench, resulting in a voltage increase
across L1 that opposes the fault current.

20. Applications of SFCL
Three main applications areas are Fault-current limiter in the main position the fault-current limiter FCL protects the
entire bus
Fault-current limiter in the feeder position the fault-current limiter FCL protects an
individual circuit on the bus. Underrated
equipment can be selectively protected as
needed in this manner.
Fault-current limiter in the bus-tie position

21. Advantages of SFCL
In comparison to conventional
technology, SFCL provide -
 Faster response time
 Shorter recovery time
Time-adjustable response
functions