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Most industrial technologies are automated by sensitive electric parts such as programmable logic controllers(PLCs) and magnetic contactors which are required high power quality. The voltage sags occur in the non-faulted power distribution feeders during the fault duration. Therefore, voltage causes economic losses in the production process of various companies. To solve the fault current and the voltage sags, the superconducting fault current limiter (SFCL) is in the spotlight. The SFCL where was located on starting point of the feeder improves the reliability of the facility by reducing the fault current. In addition, it compensates the voltage sags on the bus-bar. In this paper, evaluating the voltage sags based on fault location in the power distribution system with the SFCL through PSCAD/EMTDC simulation. Next, the expected the voltage sags frequency is predicted by the reliability analysis technique of the power distribution system. The expected voltage sags frequency of the power distribution feeder is compared with before and after the application of the SFCL. [ABSTRACT FROM AUTHOR]

This paper proposes automatic power changeover switch system applied superconducting fault current limiter (SFCL) of the Korea electric railway using 25 kV-AC Scott transformer. The electric railway needs neutral section to separate two different electrical power phase to m phase and t phase. While the train passes through the neutral section, the electrical power supply phase is changed over to other phase. And that time, the train must turn off the circuit breaker to avoid transient as ‘inrush-current’ and ‘arc’. These cause negative problems as speed decline of the train, a shorter life of the train circuit breaker. To improve the problems, the inrush current limitation method is proposed. In addition, we analysed the effect of proposed method using time-domain transient simulation software (PSCAD/ EMTDC). [ABSTRACT FROM PUBLISHER]

In this study, we analyse the coordination of protective relays between a primary feeder and an interconnecting transformer grounded by using a superconducting fault current limiter (SFCL) of a wind farm. Most wind farms and utility systems are interconnected by a transformer. The winding configuration of most interconnecting transformers is wye grounded-delta. Therefore, the utility-side grounding of the interconnecting transformer can support a new single line-to-ground fault current path. Because the coordination plan of a protective relay in a power distribution system does not consider the new fault path, an unintended relay operation can occur. To overcome this problem, an SFCL is applied to the ground connection of the interconnecting transformer. We analyse the effect of the resistive SFCLs on the coordination of the ground faults using time-domain transient simulation software (PSCAD/EMTDC). [ABSTRACT FROM PUBLISHER]

In this paper, we propose a protection scheme using a superconducting fault current limiter (SFCL) for the electric railway with traction power supply system with the automatic power changeover switch (ACS) system. The Korean electric railway uses a Scott transformer with many traction power substations. Each traction power substation has a neutral section. The ACS system is being installed at the neutral section and studied. In this system, shorting between the M- and T-phases prevents phase-to-phase faults, which was not considered for the conventional AC railway, due to the ACS. The proposed protection scheme using the SFCL mitigates this problem. In addition, we analysed the effect of the proposed protection scheme using the time-domain transient simulation software PSCAD/EMTDC. [ABSTRACT FROM PUBLISHER]

In this paper, the application method of superconducting fault current limiter (SFCL) for the protection coordination of the protective devices in a power distribution system was analyzed. The SFCL has been announced as better solution among many methods to limit a fault current effectively, which has continuously increased due to more complex network of a power system. However, the application of the SFCL in a power system affects the operation of the protection devices and the protection coordination, which requires the study on the protection coordination of the protective devices considering the application of the SFCL in a power distribution system. [ABSTRACT FROM PUBLISHER]

Generally, the peak amplitude of the fault current after the fault occurrence depends on the transient component of the fault current, which is determined by the fault condition such as the fault angle. In the suggested flux-lock type superconducting fault current limiter (SFCL), the fault current of the lower peak amplitude causes the only high-TC superconducting (HTSC) element connected in series with one of two coils comprising the flux-lock type SFCL to be quenched, which the fault current can be limited by the lower limiting impedance of the flux-lock type SFCL. On the other hand, the fault current with the higher peak amplitude makes another HTSC element connected with the third winding to be quenched after the HTSC element connected in series with one of the SFCL's two coils is quenched, which contributes to the higher limiting impedance of this SFCL. Therefore, the effective fault current limiting operation of the flux-lock type SFCL can be performed by generating the SFCL's limiting impedance in proportion to the peak amplitude of the fault current. To confirm the current limiting operation of the proposed flux-lock type SFCL, the short-circuit tests of the flux-lock type SFCL using its third winding according to the fault angle were carried out and its effective fault current limiting operations were discussed. [ABSTRACT FROM AUTHOR]

In this paper, the effects on the protective coordination of a superconducting fault current limiter (SFCL) with the protective devices were analyzed. The SFCL has been noticed as the best solution to limit fault current effectively, which has continuously increased due to the expansion of the power facilities for the increased power demand. However, the application of the SFCL in the power system affects the protective coordination of the existing protective devices and can deviate their operation time from the original one. Therefore, the studies on the protective coordination considering the introduction of the SFCL are necessary prier to its installation. [ABSTRACT FROM AUTHOR]

This paper assesses and analyses the effects of superconducting fault current limiter (SFCL) installed in power distribution system on voltage sags. First of all, resistor-type SFCL is modeled using PSCAD/EMTDC to represent the quench and recovery characteristics based on the experimental results. Next, typical power distribution system of Korea is modeled. When the SFCL is installed in various locations from the starting point to end point of feeders, improvement of voltage sag is evaluated using the Information of Technology Industry Council (ITIC) curve of customer's loads when a fault occur. Finally, future studies needing to apply SFCL to power distribution system are presented [ABSTRACT FROM AUTHOR]