This document discusses surge current protection using superconductors. It defines surge current as the maximum instantaneous current drawn by an electrical device when first turned on, which can be 100 times the normal steady state current. Surge current can damage electrical systems. Superconductors conduct electricity with zero resistance below a critical temperature. The document proposes using superconductors as surge current limiters, which maintain low impedance during normal operation but insert high impedance during surges to limit the current. Superconducting surge current limiters offer benefits like safety, reliability and protecting electrical systems from faults.

1. By
V. Vamshi Krishna
18S45A0258
SURGE CURRENT PROTECTION
USING SUPER CONDUCTORS

2. INTRODUCTION
 Modern power system are growing fast with more
generators, transformers and large network in the system,
whenever a fault occur there is a need for the protecting
of these system.
 Here we discussed the use of superconductor as
protective device for the surge current protection.
 Superconductors conduct electricity, offering zero
resistance at certain temperature.

3. WHAT IS SURGE CURRENT
 The maximum instantaneous input current drawn by an electrical
device when first it is turn ON, is defined as surge current.
 Surge current ca be as higher as 100 time the normal steady state
current.

4. Surge current waveform

5. Need of surge current protection
 High inrush current can affect the electrical systems by tripping
fuses and circuit breakers unnecessarily.
 If inrush protection is not in place, relays and circuit breakers
must be rated higher than any possible inrush current.
 Inrush current can also cause pitted contacts on switches and
relays due to arcing of the contacts.
 This surge current can cause component damage and/or failure
within the equipment itself, blown fuses, tripped circuit breakers .

6. What is superconductor
 Metallic elements, alloys or compounds that will conduct electricity
without resistance below a certain temperature, is called a
superconductor.
 The Dutch physicist ‘HEIKE KAMERLINGH ONNES’ of Leiden
university was the first person to observe superconductivity in
mercury.
 Superconductivity is a phenomenon of exactly zero electrical
resistance that apply in certain materials when cooled below critical
temperature.
 Superconductors are extraordinary because they take no energy to
make current flow .So no energy is lost to friction to sustain the
current.

7. TYPES OF SUPERCONDUCTOR
 Low temperature superconductor:- Those whose critical temperature is below
77 k.
Example :- lead and mercury etc.
 High temperature superconductor :- Those whose critical temperature is above
77 k.
Example :- YBCO, BSCCO etc.
YBCO-Yttrium barium copper oxide
BSCCO-Bismuth strontium calcium copper oxide

8. SURGE CURRENT LIMITER
A surge current limiter is a device which limit
Prospective surge current when a instant high Current
occurs at starting . generally SCL are Superconductor
SCL.

9. How does it works ?
 Superconductor SPD (surge protection device) or
SCL(surge current limiter) prevents the current from
exceeding a given value.
 It presents a negligible impedance for normal current
value.
 It naturally and automatically inserts a high impedance
above a given current.
 Superconductor spd’s impedance disappears automatically
after the surge clearance and a certain delay.

10. SUPERCONDUCTIVE SCL

11. (i) If current flow normally then ;
(ii) If surge current flows then ;

12. Why we use superconductors ?
 The losses are reduced by using superconductors.
 The best conductivity is provided by using
superconductors.
 These are the ideal conductors.

13. Other Methods For Surge Current
Protection
 Resistors
 Thyristors
 TRIACS
 Inductors
 NTC Thermistor

14. Advantages:-
 Safety, reliability, and power quality.
 Cost for circuit breaker And fuses can be reduced.
 Life of transformers extended.
 Reduced or eliminate wide area, blackouts.

15. APPLICATIONS
 We can implement this method to protection the electrical system
from threats.
 The true application for the superconducting FCL is at
transmission voltages of 500kv.

16. Conclusion
The purpose of this presentation was the study of surge
current protection using superconductors. The
Superconductor Fault Current Limiters offers efficient
advantages to power systems and opens up a major
application for superconducting materials.