Valentin Abe Rafael Mihali FAULTCURRENT LIMITATION IN SLOVENIAN

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

Contents of the presentation o Introduction o Effect of topology on fault currents o Devices for fault-current limitation o Fault currents in Slovenian electricpower system o Conclusions

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

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

The effect of bus coupler

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

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

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

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

Devices with explosive charge “IS-limiter”

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

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