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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]

The increase of various dispersed generations (DGs) such as wind power and solar cell in a power distribution system has been reported to increase the short-circuit current. In addition, the introduction of the DG in a power distribution system is expected to affect the operation of the protective device as well. The superconducting fault current limiter (SFCL), which has been continuously studied for the reduction of the circuit breaker's power burden, recently starts to be noticed as effective method to solve the fault current problem due to the introduction of the DG. Since the fault current limiting operation of the SFCL and the operations of the protective devices such as the over-current relay or the recloser are affected by the application location of the DG, the study on the protection cooperation of the protective devices with the SFCL considering the application location of the DG in a power distribution system is firstly required. [ABSTRACT FROM PUBLISHER]

The introduction of various dispersed generation (DG) in a power distribution system has caused the short-circuit current to increase, which can make the operation of the protective device deviate from its original set value. Especially, the increase of a short-circuit current in a power distribution system due to the increase of the DG is expected to be required for the related power utilities such as the circuit breaker to be replaced with a larger one. Among the countermeasures to solve the short-circuit problem in a power distribution system considering the increase of the DG, the superconducting fault current limiter (SFCL) has been noticed as one of the promising devices. [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, 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]

In this paper, we describes how to coordinate between recloser and fuse in power distribution system with superconducting fault current limiters (SFCL). The recloser and fuses are the main overcurrent protective devices in power distribution system. Universally, to protect against permanent faults, fuses are installed on overhead feeder laterals and the reclosers as a backup protection against temporary faults remove many unnecessary outages. Here, the recloser is set to trip using TCC curve for a temporary fault before any of the fuses can melt. If the fault is a permanent fault, the fuse has to melt just before the last delay trip of the recloser. However, the application of a resistive SFCL in power distribution system affects the recloser- fuse operation and coordination as decreased fault currents. In case that when a permanent fault occurs, the recloser could be locked-out after the last delay trip before the fuses operate. [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]

We suggested that the neutral line is a more effective location for a superconducting fault current limiter (SFCL) in a three-phase power system. To confirm it, we analyzed the quench and recovery characteristics of SFCL applied into the neutral line in cases of non-symmetrical ground faults, such as single line-to-ground and double line-to-ground faults. Through a comparative analysis based on the experimental results for two SFCLs applied either to the neutral line or to the three-phase power line, it was confirmed that the SFCL applied into the neutral line of the power system was more advantageous from the viewpoint of both the practical use of the SFCL and the SFCL's coordination with other related protective devices in the power system. [ABSTRACT FROM AUTHOR]

As the application of low-voltage-direct-current system increases, fault analysis in the low-voltage-direct-current system has essential because the fault response has different from the conventional AC distribution system. Especially, the fault current by the discharge current of the capacitor in the low-voltage-direct-current distribution system has very large compared with the conventional AC distribution system. Therefore, this paper proposed the application of the superconducting fault current limiter for limiting the fault current on the low-voltage-direct-current system. As one of the protected methods against fault current, the superconducting fault current limiter which could quickly limit the fault current has been noticed as an attractive method. However, the protection relay may malfunction such as over current relay, selective protection relay due to limiting fault current by applying superconducting fault current limiter. Therefore, in this paper proposed a solution to malfunction problem of the protection relay using the voltage components of the high temperature superconductivity. This paper verified the effect of the proposed method through test modelling and PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

The penetration of wind turbine generators onto the grid has grown worldwide at unprecedented rates in recent years. This raises the concern that the tripping of wind turbine generators could potentially cause system collapses. To alleviate these concerns, wind turbine generators need to maintain connection with the grid when a grid fault occurs. This has provoked many countries to adopt low-voltage ride-through (LVRT) for wind turbine generators. The LVRT is the capability of wind turbine generators to maintain connectivity during certain periods of voltage sag. The wind turbine generators should be connected to the grid to support fault recovery. Also, wind turbine generators must provide reactive power according to the grid voltage sag. Therefore, much research has been focused on enhancing LVRT capability. To enhance LVRT capability, this paper proposes the application of a superconducting fault current limiter (SFCL) in the system. The fault current was suppressed and the voltage sag was improved through the application of the SFCL. By improving the voltage sag, the wind turbine generator and the grid were able to maintain a connection. However, suppression of the fault current can cause a problem in the overcurrent relay (OCR) trip time delay. The trip time delay was solved by OCR resetting. Through a power system computer-aided design/electromagnetic transients including DC (PSCAD/EMTDC), the enhancement of LVRT capability and improvement of the trip delay was confirmed. [ABSTRACT FROM AUTHOR]

In this paper, we propose a protection scheme using a superconducting fault current limiter (SFCL) for the power transmission system with Thyristor Controlled Series Capacitor (TCSC). TCSC can lead effectiveness such as power flow control, increase in transmission capacity, and improvement for system transient phenomena. But, because this has same effect to the reducing series impedances in transmission system, there are serious problem such as increase in fault current, transient stability deterioration and series voltage stress of TCSC in the transmission line. The proposed protection scheme using the SFCL into TCSC configuration can mitigate these problems. In addition, SFCL can be expected to protect the TCSC from a large transient current generated by lightning or switching surge in power transmission system. To verify the effect of the proposed protection scheme, PSCAD/EMTDC is used. From simulation result, we had good results for fault current limitation and insulating protection of TCSC. [ABSTRACT FROM AUTHOR]