The document describes experimental tests of a self-triggering high temperature superconducting fault current limiter (SFCL). It discusses: 1) The SFCL consists of a non-inductive HTS module and reactor to limit fault currents in power grids. 2) During normal operation, the SFCL has low impedance but during faults its HTS resistance rapidly increases to limit current. 3) Tests measured the SFCL's critical current and AC losses under different frequencies and operating currents to characterize its performance.

1. EXPERIMENTAL TESTS OF CRITICAL CURRENT
AND AC LOSS FOR A SELF-TRIGGERING HIGH
TEMPERATURE SUPERCONDUCTING FAULT
CURRENT LIMITER (SFCL) WITH MAGNETO-
BIASED FIELD

2. INTRODUCTION:
• Rapidly growing power demands account for an increasing level of short circuit fault
current in recent years. It is difficult for the conventional circuit breaker to meet the
capacity requirements for fault current limiting.
• High temperature superconducting fault current limiter (SFCL) can instantaneously
protect power grids by using the HTS quench properties.
• SFCL has a non-inductive high temperature superconducting module, a reactor with
two split symmetrical windings and a circuit breaker.
• The critical current and AC loss characteristics of a SFCL unit have been tested and
compared considering the effects of joints.

3. PROBLEM IN POWER GRID:
• When power demand increasing , the critical fault current increases. This problem is
solved by high impedance transformer and a reactor but they cause transmission loss,
effect the voltage regulation capacity and increase the cost of power grid.
• This problem can be resolved by using High temperature superconducting fault
current limiter.
• SFCL has advantages like:
• Quick response
• Self-triggering
• Low loss
• High current performance

4. SFCL :
• There are three common methods for AC loss measurement, which are electrical
method, magnetic method and thermal method.
• The electrical measurement method has high accuracy and fast speed, however, it is
easy to be interfered by the test environment.
• A novel magneto-biased SFCL was proposed firstly which has two-level current
limiting ability. It is capable to trigger automatically during this two-level fault current
limiting period.
• The inductive voltage compensation measuring principle is applied to build a
measurement system for AC losses then its results are compared and analyzed under
the various frequencies and different operation currents.

5. OPERATION OF SFCL:
• In the First stage, the non-
inductive HTS module doesn’t take
place quench, the reactance of the
two branches of L1 and L2 is the
leakage reactance and the induced
voltage of two branches is a
mutual voltage which cancels each
other. Because the impedances of
the reactor and non-inductive HTS
module are very small, they have
little influence on the normal
operation of the power grid.

6. OPERATION OF SFCL:
• In the second period, the current of i1 and i2 increases sharply due to the fault current
takes place.
• The resistance of the non inductive HTS module grows quickly after i2 exceeds the
critical current of superconductor. he non-inductive HTS module self-triggers and
decreases the fault current.
• Because the reactance of the two branches is not the same, the quench resistance of
HTS module causes the most short-circuit fault current transfers to branch of L1.
• After that, circuit breaker K1 triggers itself to open when the resistance of non-
inductive HTS module achieves its quench value.

7. OPERATION OF SFCL:
• In the third period, branch of L2 is disconnected and only branch of L1 is
connected to the circuit. The current of branch of L2 is 0.
• The non-inductive HTS module quickly return to the superconducting state and
the next closure of circuit breaker K1 is ready for self-triggering.
• Therefore, the branch of L1 impedance limits the fault current further after K1
opens. Until K2 is open, this SFCL can complete the second level of current
limiting.

8. CONSTRUCTION OF SFCL:
• The HTS module is made from ten non-
inductive superconducting units in series.
• Each superconducting unit has positive
and negative S-bend winding and includes
four segments of superconducting tapes.
• The current flows from Joint 1 to Joint 2.
The tape voltage of each segment is V1,
V2, V3 and V4.

9. REPLICATE PROBLEM IN ETAP:
• In the shown single line diagram there is no
distribution generator , the fault current value
is 13.2 KA.

10. REPLICATE PROBLEM IN ETAP:
• When the distribution generator is applied,
then short circuit current rating is 22.8 KA.
• Short circuit rating increased due to the
installation of distribution generator.

11. REPLICATE PROBLEM IN ETAP:
• SCFL is a self-acting system this type
limiter protects grid from damaging
current peaks.
• Due to placement of the series reactor
the short circuit rating is reduced to
16.15 KA.

12. FUTURE WORK:
• SFCL can be placed at new generating units which will help in increase the power
transfer capability of transmission system and operating the distributed
generation with effective manner.

13. THANKS
• ANY QUESTION YO MAY ASK.