1. Komunalna energetika 2014, Maribor, Slovenija
Valentin Ažbe
Rafael Mihalič
FAULT-CURRENT LIMITATION IN SLOVENIAN ELECTRIC-POWER TRANSMISSION SYSTEM
OMEJEVANJE KRATKOSTIČNIH TOKOV V SLOVENSKEM ELEKTRIČNEM PRENOSNEM OMREŽJU
Komunalna energetika 2014, Maribor, Slovenija  

2. Contents of the presentation
Introduction
Effect of topology on fault currents
Devices for fault-current limitation
Fault currents in Slovenian electric-power system
Conclusions

3. Introduction
Developement of electric-power system enables better reliability, stability and quality of electric-energy supply…
On the other hand, short-circuit power is also increasing - withstand capacity can be exceeded.

4. Methods for fault-current limitation
Topological measures
Devices – fault current limiters
The effect of bus coupler

5. The effect of bus coupler

6. Fault current limiters
Current limiting reactors
Solid-state devices
Devices that apply superconductors
Devices with explosive charge – IS-limiter
FACTS devices
Magnetic fault current limiter
Devices with PTC resistors

7. Current limiting reactors
Permanently connected
Connected in series to electric-power system
Air-core reactors

8. Solid state devices GTO or IGBT
Limitation or interruption of fault current
Expensive

9. Super-conducting Fault Current limiters (SCFCL)
Resistive or inductive SCFCL
Very low impedance in normal operation
Increased impedance at faults
Still in research / test phase
Weak point: energy needed for cooling of superconductor

10. Devices with explosive charge “IS-limiter”

11. Fault current in slovenian EPS
For year 2030, in [kA]
measures
With-out
5 Ω
10 Ω
15 Ω
20 Ω
Separa-tion
Substation RTP Beričevo
57,4
41,0
38,1
36,9
36,1
33,4
Substation RTP Kleče
57,3
41,6
38,0
36,3
35,3
31,8
Withstand capacity: 40 kA

12. Conclusions
Sooner or later, fault currents will reach substations’ withstand capacity
Only topological measures and current limiting reactors are currently available
Other fault current limiters are in research/developement phase