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AŽBE, V., MIHALIČ, R.
FAULT-CURRENT LIMITATION IN SLOVENIAN ELECTRIC-POWER TRANSMISSION SYSTEM
KOMUNALNA ENERGETIKA / POWER ENGINERING, 10
Reinforcement of electric-power systems (EPS) with construction of new power lines, additional interconnections between networks, a growth in generating capacity and upgrade to a higher voltage levels (e.g., from 220 kV to 400 kV) is a natural and logical way of development of EPS in order to improve the stability and reliability. However, on the other side, these reinforced networks can reach or even exceed their limits with respect to the short-circuit current withstand capability. The problem of too high fault currents can be firstly expected in reinforced networks that supply big cities. This paper presents and discusses various methods for limiting these fault currents in 110 kV electric-power network. These methods can be either passive (i.e., increase of impedance at nominal and fault conditions) or active (i.e., small impedance at nominal load and fast increase of impedance at fault occurrence). As typical structure of substation at 110 kV level is in the form of double busbar with two transformers, special attention is paid on inserting fault-current limiters at the position of bus coupler. The results of application of various fault current limiters are presented on the case of Slovenian EPS for the year 2030.
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