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Sung-Hun Lim
Department of Electrical Engineering, Soongsil University, 369 Sangdo-ro, Dongjak-gu, Seoul 156-743, Korea

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Journal article
Published: 09 July 2021 in Energies
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In this paper, direct current (DC) fault current limiting and interrupting operation of hybrid DC circuit breaker (DCCB) using double quench, which consists of DCCB, a series resonance circuit, power electronic switch, surge arrestor, two separated current limiting reactor/resistor, and two superconducting elements, were suggested. The suggested hybrid DCCB can perform the interrupting operation after twice or once DC fault current limiting operation according to DC fault current amplitude. To verify the effective operation of the suggested hybrid DCCB, the modeling for the components of DCCB, the surge arrestor, and the SCE was carried out and its DC operational characteristics were analyzed. Through the analysis of the modeling results for the suggested hybrid DCCB, the advantages of hybrid DCCB were discussed.

ACS Style

Sang-Jae Choi; Jun-Hyup Lee; Jin-Wook Lee; Sung-Hun Lim. Improvement of DC Fault Current Limiting and Interrupting Operation of Hybrid DC Circuit Breaker Using Double Quench. Energies 2021, 14, 4157 .

AMA Style

Sang-Jae Choi, Jun-Hyup Lee, Jin-Wook Lee, Sung-Hun Lim. Improvement of DC Fault Current Limiting and Interrupting Operation of Hybrid DC Circuit Breaker Using Double Quench. Energies. 2021; 14 (14):4157.

Chicago/Turabian Style

Sang-Jae Choi; Jun-Hyup Lee; Jin-Wook Lee; Sung-Hun Lim. 2021. "Improvement of DC Fault Current Limiting and Interrupting Operation of Hybrid DC Circuit Breaker Using Double Quench." Energies 14, no. 14: 4157.

Journal article
Published: 04 May 2021 in Electronics
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In this paper, a DC fault short circuit was conducted to analyze the DC fault current limiting characteristics of a flux-coupling type superconducting fault current limiter (SFCL) that has two coils connected in series via one iron core. Similar to the AC power system, the flux-coupling type SFCL in a DC system, which has the two coils connected with each other in series and the secondary coil connected with the superconducting element in parallel, remains in the superconducting state before a short-circuit accident occurs. This results in magnetic flux getting generated by the two windings connected in series offsetting each other and the induced voltage at the two windings remaining at zero. However, in the event of a short-circuit accident on the DC line, a resistance is generated on the superconducting element, so that the magnetic flux generated at the two windings no longer offsets each other. Therefore, a voltage is induced on the two windings, and the fault current is limited accordingly. As a result of configuring a DC short-circuit device and experimenting with this SFCL, we could confirm the DC fault current limiting effect of a flux-coupling type SFCL with two windings connected in series. In addition, we could establish performance conditions of the flux-coupling type SFCL in a DC system by inferring the fault current, operating current, and limited impedance equations according to the connection direction of the flux-coupling type SFCL with two windings connected in series and by analyzing fault current limiting degree, power burden, magnetic flux, and energy consumption for each element composing the SFCL.

ACS Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. DC Current Limiting Operation and Power Burden Characteristics of a Flux-Coupling Type SFCL Connected in Series between Two Windings. Electronics 2021, 10, 1087 .

AMA Style

Seok-Cheol Ko, Tae-Hee Han, Sung-Hun Lim. DC Current Limiting Operation and Power Burden Characteristics of a Flux-Coupling Type SFCL Connected in Series between Two Windings. Electronics. 2021; 10 (9):1087.

Chicago/Turabian Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. 2021. "DC Current Limiting Operation and Power Burden Characteristics of a Flux-Coupling Type SFCL Connected in Series between Two Windings." Electronics 10, no. 9: 1087.

Journal article
Published: 26 April 2021 in Energies
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DC faults cause severe disruption in not only the DC system but also the AC system because the fault current is very large and rapidly increases. The DC circuit breaker used to separate the DC faults from the power system is still being researched, but it is very expensive due to the use of multiple power semiconductors to interrupt a large fault current in a short time. However, if the quench characteristic of a superconductor is used, the amplitude of fault current can be reduced. Therefore, it is possible to effectively interrupt a large fault current even if a relatively cheap mechanically passive DC circuit breaker is used. In the current study, a superconducting hybrid DC circuit breaker is proposed, and the limiting characteristics of each element are analyzed. By using two superconducting elements, the quench occurs sequentially twice according to the magnitude of the fault current, and the current-limiting reactor and resistance are used. If a current-limiting reactor is used in the DC system, the fault current rises slowly at the beginning of the fault, and the use of resistance can reduce the magnitude of the fault current. The inductance of the current-limiting reactor and resistance parameter settings of the hybrid DC circuit breaker was analyzed by the step-changing case method, and the interrupting characteristic of the DC circuit breaker was improved.

ACS Style

Sang-Jae Choi; Sung-Hun Lim. Impact on Current-Interrupting Characteristic by Parameter Settings of Superconducting Hybrid DC Circuit Breaker. Energies 2021, 14, 2469 .

AMA Style

Sang-Jae Choi, Sung-Hun Lim. Impact on Current-Interrupting Characteristic by Parameter Settings of Superconducting Hybrid DC Circuit Breaker. Energies. 2021; 14 (9):2469.

Chicago/Turabian Style

Sang-Jae Choi; Sung-Hun Lim. 2021. "Impact on Current-Interrupting Characteristic by Parameter Settings of Superconducting Hybrid DC Circuit Breaker." Energies 14, no. 9: 2469.

Journal article
Published: 26 March 2021 in IEEE Transactions on Applied Superconductivity
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In the DC system, a larger fault current flows due to capacitor discharging than in an AC system. In the event of a fault in the MTDC (multi-terminal DC), although the magnitude of the cur-rent flowing through each DCCB (DC circuit breaker) varies de-pending on the fault location, all capacitors in MTDC may dis-charge and all DCCB may interrupt. In this paper, the trigger type SFCL (superconducting fault current limiter) was con-structed to limit large fault current, and DC OCR (overcurrent relay) was designed to prevent interrupting malfunction accord-ing to the impact of SFCL. When the fault current was small by operation of SFCL, the DCCB did not interrupt or trip time is delayed. These problems cause malfunction even when DC OCR is applied. Therefore, DC OCR requires an additional correction method. In this paper, a new correction method was proposed in consideration of the current direction and voltage slope. The sim-ulation was conducted according to four cases, and the proposed OCR correction was verified to eliminate malfunctions through case studies.

ACS Style

Sang-Jae Choi; Sung-Hun Lim. Directional Correction of Over-Current Relay using Voltage Slope in Multi Terminal DC System with SFCL. IEEE Transactions on Applied Superconductivity 2021, PP, 1 -1.

AMA Style

Sang-Jae Choi, Sung-Hun Lim. Directional Correction of Over-Current Relay using Voltage Slope in Multi Terminal DC System with SFCL. IEEE Transactions on Applied Superconductivity. 2021; PP (99):1-1.

Chicago/Turabian Style

Sang-Jae Choi; Sung-Hun Lim. 2021. "Directional Correction of Over-Current Relay using Voltage Slope in Multi Terminal DC System with SFCL." IEEE Transactions on Applied Superconductivity PP, no. 99: 1-1.

Journal article
Published: 23 March 2021 in IEEE Transactions on Applied Superconductivity
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Three-phase transformer type superconducting fault current limiter (SFCL) using two common connection points between secondary windings, which consisted of three-phase transformer windings wound on three legs of E-I iron core and two/three su-perconducting modules (SCMs), were suggested and its fault current limiting operations according to ground-fault types were analyzed. To verify the effective operation of the three-phase transformer type SFCL using two common connection points be-tween secondary windings, the unsymmetrical ground and the symmetrical ground faults were applied into three-phase power simulated system with the suggested SFCL. For the comparison, the ground faults were generated into three-phase transformer type SFCL with two/three SCMs. Through analysis on the test results, the SFCL with two SCMs was confirmed to have no dif-ferent fault current limiting operation from the SFCL with three SCMs. The structure of E-I iron core with three magnetically coupled legs and the constitution of three secondary windings with two common connection points were analyzed to be con-tributed to the same fault current limiting operation. Further-more, the power consumption and the joule energy of the SCMs comprising both the SFCL with two SCMs and the SFCL with three SCMs during the fault period had shown to be almost the same except for the transient period due to the quench time dif-ference in case of the single-line ground fault.

ACS Style

Tae-Hee Han; Seok-Cheol Ko; Sung-Hun Lim. Fault Current Limiting Operations of Three-Phase Transformer Type SFCL using Two Common Connection Points Between Secondary Windings. IEEE Transactions on Applied Superconductivity 2021, PP, 1 -1.

AMA Style

Tae-Hee Han, Seok-Cheol Ko, Sung-Hun Lim. Fault Current Limiting Operations of Three-Phase Transformer Type SFCL using Two Common Connection Points Between Secondary Windings. IEEE Transactions on Applied Superconductivity. 2021; PP (99):1-1.

Chicago/Turabian Style

Tae-Hee Han; Seok-Cheol Ko; Sung-Hun Lim. 2021. "Fault Current Limiting Operations of Three-Phase Transformer Type SFCL using Two Common Connection Points Between Secondary Windings." IEEE Transactions on Applied Superconductivity PP, no. 99: 1-1.

Journal article
Published: 17 March 2021 in IEEE Transactions on Applied Superconductivity
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As the importance of renewable energy increases, the capacity of dispersed generations (DGs) has increased worldwide. However, the connection of DGs in the power distribution system can cause the fault current to increase as well as malfunction of the overcurrent relay (OCR) due to the reverse directional fault current. As the countermeasure to limit the fault current in the power distribution system with DG, though the superconducting fault current limiter (SFCL) is reported to be more effective, the research on the protection algorithm of the protective relay considering the application of SFCL is preferentially required. In this paper, the correction method of the OCR using voltage components for application of SFCL in a power distribution system with DG was suggested. To verify the effectiveness of the suggested method, the fault simulation for the power distribution system with DG including the OCR and the SFCL was performed. By applying the proposed correction method in the OCR, the protection coordination of OCRs for the application of SFCL in power distribution system with DG was confirmed to be improved through the suppression of the malfunction of the OCR.

ACS Style

Sung-Hun Lim; Min-Ki Park. Analysis on Protection Coordination of OCRs using Voltage Components for the Application of SFCL in a Power Distribution System with DG. IEEE Transactions on Applied Superconductivity 2021, PP, 1 -1.

AMA Style

Sung-Hun Lim, Min-Ki Park. Analysis on Protection Coordination of OCRs using Voltage Components for the Application of SFCL in a Power Distribution System with DG. IEEE Transactions on Applied Superconductivity. 2021; PP (99):1-1.

Chicago/Turabian Style

Sung-Hun Lim; Min-Ki Park. 2021. "Analysis on Protection Coordination of OCRs using Voltage Components for the Application of SFCL in a Power Distribution System with DG." IEEE Transactions on Applied Superconductivity PP, no. 99: 1-1.

Journal article
Published: 04 February 2021 in IEEE Transactions on Applied Superconductivity
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Superconducting fault current limiters (SFCLs) are emerging as an alternative to limit fault current in AC and DC power systems. SFCLs can perform faster current limiting operation and auto-matic fault current detection and recovery, regardless of the type of fault. In this paper, a laboratory-scale prototype SFCL was fabricated and analyzed for its magnetization characteristics due to the magnetizing current according to the change of the number of windings in pairs. This bridge type SFCL consists of two windings and two high-Tc superconducting (HTSC) elements on one iron core. When the number of windings of the two coils were changed in pairs, the variation of the induced voltage and Joule losses due to the magnetizing current, magnetic flux in each winding, and power losses for the bridge type SFCL were compared with each other. Through comparative analysis, it was confirmed that the size of the number of turns should be considered to reduce the power losses of SFCL while effectively limiting the fault current during the fault cycle.

ACS Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. Magnetization and Power Losses Characteristics Due to Variation in the Number of Windings of Bridge Type SFCL with Double HTSC Elements. IEEE Transactions on Applied Superconductivity 2021, PP, 1 -1.

AMA Style

Seok-Cheol Ko, Tae-Hee Han, Sung-Hun Lim. Magnetization and Power Losses Characteristics Due to Variation in the Number of Windings of Bridge Type SFCL with Double HTSC Elements. IEEE Transactions on Applied Superconductivity. 2021; PP (99):1-1.

Chicago/Turabian Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. 2021. "Magnetization and Power Losses Characteristics Due to Variation in the Number of Windings of Bridge Type SFCL with Double HTSC Elements." IEEE Transactions on Applied Superconductivity PP, no. 99: 1-1.

Journal article
Published: 08 November 2020 in Energies
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Due to the increase in DC load and DC Power generation, the need for DC power system is emerging. Accordingly, FRT (fault ride through) and LVRT (low voltage ride through), which are related regulations for renewable energy sources, have been enacted, and operation algorithms of each converter are required for this. However, the operation of the converter according to LVRT regulations causes DC voltage fluctuations. In the current study, DC voltage fluctuation is suppressed through converter control of DC-linked battery. The controller was designed from the relational equation between DC voltage and instantaneous power of battery. The pattern of DC voltage fluctuations to the output of the PV (photovoltaic), which is a DC power generation source, was confirmed, and voltage fluctuation suppression was verified by applying the designed converter cooperation algorithm and controller.

ACS Style

Sang-Jae Choi; Sung-Hun Lim. Fluctuation Suppression of DC-Link Voltage Using Control of Converters Connected with DC Distributed Generation. Energies 2020, 13, 5832 .

AMA Style

Sang-Jae Choi, Sung-Hun Lim. Fluctuation Suppression of DC-Link Voltage Using Control of Converters Connected with DC Distributed Generation. Energies. 2020; 13 (21):5832.

Chicago/Turabian Style

Sang-Jae Choi; Sung-Hun Lim. 2020. "Fluctuation Suppression of DC-Link Voltage Using Control of Converters Connected with DC Distributed Generation." Energies 13, no. 21: 5832.

Journal article
Published: 22 October 2020 in Energies
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In this study, the characteristics of the double quench and instantaneous power of a superconducting fault current limiter (SFCL) using two magnetically coupled windings were analyzed. In the proposed model of SFCL, two magnetically coupled windings are wound on the iron core and each winding is connected to one superconducting element. When a fault occurs, the SFCL can limit the fault current by the double quench occurrence of two superconducting elements. In order to analyze the influence of the winding direction on the fault current limiting characteristics of the proposed SFCL, two magnetically coupled windings were designed to allow the same and the reverse directions. From the simulated short circuit experiment, the currents and the voltages of two coupled windings and two superconducting elements were measured and the instantaneous power and the double quench occurrence were analyzed. It was confirmed from the experimental results analysis that the fault current limiting characteristics of the SFCL were more favorable in the reverse winding direction than in the same winding direction.

ACS Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. Analysis on Double Quench and Instantaneous Power of SFCL Using Two Magnetically Coupled Windings According to Winding Direction. Energies 2020, 13, 5533 .

AMA Style

Seok-Cheol Ko, Tae-Hee Han, Sung-Hun Lim. Analysis on Double Quench and Instantaneous Power of SFCL Using Two Magnetically Coupled Windings According to Winding Direction. Energies. 2020; 13 (21):5533.

Chicago/Turabian Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. 2020. "Analysis on Double Quench and Instantaneous Power of SFCL Using Two Magnetically Coupled Windings According to Winding Direction." Energies 13, no. 21: 5533.

Journal article
Published: 02 October 2020 in Energies
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In this paper, a superconducting fault current limiting breaker (SFCLB) using flux coupling with a tap changer is suggested and its effective fault current limiting and breaking characteristics due to the winding method using its tap changer are analyzed. The suggested SFCLB using flux coupling, which consists of the SFCLB using flux coupling with a tap changer, mechanical switch and driving coil, can perform the circuit-breaking function without external driving power after the fault current limiting operation. To examine the suggested SFCLB’s operation, the small scale SFCLB using flux coupling was fabricated and alternative current (AC) short-circuit experiments due to the winding method using the tap changer of the SFCLB were executed. From the experimental results, a lower fault current limiting rate and faster breaking time in the case of a SFCLB with a series connection could be obtained compared to one with a parallel connection.

ACS Style

Sung-Hun Lim; Jin-O. Kim; Youngjin Jeong. Fault Current Limiting and Breaking Characteristics of SFCLB Using Flux Coupling with Tap Changer. Energies 2020, 13, 5138 .

AMA Style

Sung-Hun Lim, Jin-O. Kim, Youngjin Jeong. Fault Current Limiting and Breaking Characteristics of SFCLB Using Flux Coupling with Tap Changer. Energies. 2020; 13 (19):5138.

Chicago/Turabian Style

Sung-Hun Lim; Jin-O. Kim; Youngjin Jeong. 2020. "Fault Current Limiting and Breaking Characteristics of SFCLB Using Flux Coupling with Tap Changer." Energies 13, no. 19: 5138.

Original article
Published: 08 September 2020 in Journal of Electrical Engineering & Technology
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In this paper, a transformer type superconducting fault current limiter (SFCL) with two isolated secondary windings was fabricated to increase the current limiting capacity. As the magnetization current increased due to the large transient fault current immediately after the fault, the magnetization force variation, the operating range of the flux linkage, and the voltage region variation were compared at fault angles of 0° and 90°, respectively. The short-circuit test analyzed the current limiting operation, power consumption, and energy consumption characteristics according to the fault angle immediately after the fault occurrence. The results showed that the fault angle of 0° could limit the fault current much more than the fault angle of 90°. In addition, it was confirmed that the magnetization force variation, the operating range of the flux linkage, and the voltage induced in the primary winding were all much larger at the fault angle of 0° than at the fault angle of 90°.

ACS Style

Tae-Hee Han; Sung-Hun Lim; Seok-Cheol Ko. Magnetization Characteristics Due to Fault Angle of Transformer Type SFCL with Two Isolated Secondary Windings. Journal of Electrical Engineering & Technology 2020, 15, 2501 -2508.

AMA Style

Tae-Hee Han, Sung-Hun Lim, Seok-Cheol Ko. Magnetization Characteristics Due to Fault Angle of Transformer Type SFCL with Two Isolated Secondary Windings. Journal of Electrical Engineering & Technology. 2020; 15 (6):2501-2508.

Chicago/Turabian Style

Tae-Hee Han; Sung-Hun Lim; Seok-Cheol Ko. 2020. "Magnetization Characteristics Due to Fault Angle of Transformer Type SFCL with Two Isolated Secondary Windings." Journal of Electrical Engineering & Technology 15, no. 6: 2501-2508.

Original article
Published: 26 August 2020 in Journal of Electrical Engineering & Technology
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Recently, the requirement of the electrical energy from the renewable source has been growing in the South Korea since government’s energy plan to generate the electrical power of 20% as renewable source. In addition, these renewable power plants have been constructed on not only the existing power plant’s side but also customer’s side. These changes in power distribution system cause the fault current to increase higher and to reverse the direction of the fault current. Variable countermeasures to reduce the fault current have been studied and the introduction of the superconducting fault current limiter (SFCL) in the power distribution system, one of them, has been actively reported. However, the installation of the SFCL can affect the power system protection because of the fault current’s decrease or increase, which depends on the construction of the power distribution system. Especially, the application of the SFCL in a closed-loop power distribution system can cause the delayed trip operation or the fast trip operation of the over-current relay (OCR), one of the representative protective devices widely used in a power distribution system. This change can influence on the existed protective coordination. In this paper, the OCR with voltage component, one of the methods to suppress its trip operation’s change in a power distribution system with a closed loop construction due to the application of the SFCL, was suggested and the protection coordination between the OCRs in a power distribution system with a closed loop was analyzed. It was confirmed that a simple using voltage component in the OCR could cause the trip variation of the reverse direction OCR in loop power system and it can be improved by matching the relaying voltage components.

ACS Style

Seung-Taek Lim; Sung-Hun Lim. Protective Coordination of the OCR with the Voltage Component in a Closed-Loop Power Distribution System with the FCL. Journal of Electrical Engineering & Technology 2020, 15, 2451 -2457.

AMA Style

Seung-Taek Lim, Sung-Hun Lim. Protective Coordination of the OCR with the Voltage Component in a Closed-Loop Power Distribution System with the FCL. Journal of Electrical Engineering & Technology. 2020; 15 (6):2451-2457.

Chicago/Turabian Style

Seung-Taek Lim; Sung-Hun Lim. 2020. "Protective Coordination of the OCR with the Voltage Component in a Closed-Loop Power Distribution System with the FCL." Journal of Electrical Engineering & Technology 15, no. 6: 2451-2457.

Journal article
Published: 14 August 2020 in Energies
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Recently, a lot of interesting research has been conducted to solve the fault current problem of the DC system. In long-distance transmission, DC transmission is more economical than AC transmission. The connection of power grids with a DC system can also better control the power flow and provide high stability. However, the control of the fault current in a DC system is more difficult to handle than in an AC system because the DC system does not make a zero point, unlike the AC system. In addition, there is a disadvantage, in that an arc occurs when a circuit breaker operates. In this paper, a new type of DC superconducting fault current limiter (SFCL) is proposed. This new type of SFCL is composed of two superconducting elements, a current limiting resistor/reactor (CLR), and a transformer. With the proposed SFCL, the DC fault current limiting experiments were performed and the DC fault current limiting characteristics of this SFCL due to the component of the CLR were analyzed.

ACS Style

Kang-Cheol Cho; Min-Ki Park; Sung-Hun Lim. Analysis of the DC Fault Current Limiting Characteristics of a DC Superconducting Fault Current Limiter Using a Transformer. Energies 2020, 13, 4210 .

AMA Style

Kang-Cheol Cho, Min-Ki Park, Sung-Hun Lim. Analysis of the DC Fault Current Limiting Characteristics of a DC Superconducting Fault Current Limiter Using a Transformer. Energies. 2020; 13 (16):4210.

Chicago/Turabian Style

Kang-Cheol Cho; Min-Ki Park; Sung-Hun Lim. 2020. "Analysis of the DC Fault Current Limiting Characteristics of a DC Superconducting Fault Current Limiter Using a Transformer." Energies 13, no. 16: 4210.

Journal article
Published: 07 April 2020 in Energies
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A bridge type superconducting fault current limiter (SFCL) with simultaneous quench using two high-temperature superconducting (HTSC) elements and two coils was fabricated to analyze the fault current limiting characteristics. Before and after the fault occurrence, the current limiting operation and the voltage waveforms of each device were compared according to the change of the input voltage. We also analyzed flux linkages and instantaneous powers of the bridge type SFCL with simultaneous quench using flux-coupling composed of HTSC elements with different critical currents. During the fault period, the magnetization power area and the flux linkage’s operating range variation due to the magnetizing current were compared with each other.

ACS Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. Magnetizing Characteristics of Bridge Type Superconducting Fault Current Limiter (SFCL) with Simultaneous Quench Using Flux-Coupling. Energies 2020, 13, 1760 .

AMA Style

Seok-Cheol Ko, Tae-Hee Han, Sung-Hun Lim. Magnetizing Characteristics of Bridge Type Superconducting Fault Current Limiter (SFCL) with Simultaneous Quench Using Flux-Coupling. Energies. 2020; 13 (7):1760.

Chicago/Turabian Style

Seok-Cheol Ko; Tae-Hee Han; Sung-Hun Lim. 2020. "Magnetizing Characteristics of Bridge Type Superconducting Fault Current Limiter (SFCL) with Simultaneous Quench Using Flux-Coupling." Energies 13, no. 7: 1760.

Journal article
Published: 28 March 2020 in Electronics
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In this paper, a bridge type superconducting fault current limiter (SFCL) with a single high-temperature superconducting (HTSC) element is proposed to allow fault current limiting operation in direct current (DC) conditions. First, the principle of operation of the bridge type SFCL with a single HTSC element using flux-coupling was presented. After the fault occurrence, the fault current limiting operation and voltage characteristics, the power load characteristics of each device, and the energy consumption of the two coils and the HTSC element were analyzed in the proposed SFCL. As a result, it is confirmed that in the case of the additive polarity winding, the power consumption and the energy consumption of the HTSC element were lower than those in the subtractive polarity winding, and the fault current limiting characteristics were excellent.

ACS Style

Tae-Hee Han; Seok-Cheol Ko; Sung-Hun Lim. Fault Current Limiting Characteristics of a Small-Scale Bridge Type SFCL with Single HTSC Element Using Flux-Coupling. Electronics 2020, 9, 569 .

AMA Style

Tae-Hee Han, Seok-Cheol Ko, Sung-Hun Lim. Fault Current Limiting Characteristics of a Small-Scale Bridge Type SFCL with Single HTSC Element Using Flux-Coupling. Electronics. 2020; 9 (4):569.

Chicago/Turabian Style

Tae-Hee Han; Seok-Cheol Ko; Sung-Hun Lim. 2020. "Fault Current Limiting Characteristics of a Small-Scale Bridge Type SFCL with Single HTSC Element Using Flux-Coupling." Electronics 9, no. 4: 569.

Journal article
Published: 17 December 2019 in Energies
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Recently, studies on connecting distributed generation (DG) to power distribution systems through DC links have been actively conducted. When a fault in feeder of this power distribution system occurs, a voltage dip can happen in the grid. In order to prevent voltage dips, there are several solutions such as the application of a superconducting fault current limiter (SFCL). If a SFCL with a larger impedance is applied, the voltage dip of the grid is effectively prevented. However, this action can bring about the malfunction or the delayed operation of the over-current relay (OCR) due to the decreased fault current, which causes another problem of protection coordination between the protective relays. On the other hand, if the impedance of the SFCL is too low, excessive reactive power is supplied by the fault ride-through (FRT) regulation and the active power is reduced. This causes an active power imbalance on the DC link and increases the DC link’s voltage. As previous solutions to prevent the rise of DC links’ voltage, the deloading method and the application of a chopper resistor have been suggested. In this paper, a technique called active power tracking control (APTC), was proposed to suppress the rise of DC links’ voltage. Case studies considering the impedance of SFCL in the constructed power distribution system were carried out, and the rise of DC links’ voltage could be effectively suppressed without any significant delay in the operation of the OCR. This study is expected to solve both the voltage dip of the grid and the rise of DC links’ voltage when distributed generation is connected to a grid.

ACS Style

Sang-Jae Choi; Sung-Hun Lim. Enhancement on the Fault Ride through Capability of Power Distribution Systems Linked by Distributed Generation due to the Impedance of Superconducting Fault Current Limiters. Energies 2019, 12, 4810 .

AMA Style

Sang-Jae Choi, Sung-Hun Lim. Enhancement on the Fault Ride through Capability of Power Distribution Systems Linked by Distributed Generation due to the Impedance of Superconducting Fault Current Limiters. Energies. 2019; 12 (24):4810.

Chicago/Turabian Style

Sang-Jae Choi; Sung-Hun Lim. 2019. "Enhancement on the Fault Ride through Capability of Power Distribution Systems Linked by Distributed Generation due to the Impedance of Superconducting Fault Current Limiters." Energies 12, no. 24: 4810.

Original article
Published: 23 October 2019 in Journal of Electrical Engineering & Technology
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The newly increased electrical energy is needed around the metropolitan area, and therefore, the transmission system is needed to be reorganized. MVDC (medium voltage direct current) system is an attractive one for constructing these new systems. This MVDC system, which is composed of two or more VSCs (voltage-sourced converters), prevents the degradation of system reliability due to renewable energy resource and is contributed to making it more stable for power supplying companies to supply the electrical power. Furthermore, to connect the increased renewable energy resource with larger capacity into the main grid through this MVDC system, the regulations such as FRT (fault ride through) for the grid have been more and more required. According to the FRT, the VSC system is required to supply the reactive current to grid when the grid voltage drops below the allowed voltage range. However, the FRT operation can cause the DC-link voltage in the MVDC system to increase. If the DC-link voltage exceeds the nominal voltage, the damage to the DC-related application may occur. In this paper, as the method to solve this problem, the application of the APTC (active power tracking control) into the MVDC system was proposed. The APTC is based on the principle that the DC-link voltage is determined by the power balance between the incoming and the outgoing active powers into the DC-link. If the outgoing active power decreases due to the short circuit in grid side, the DC-link voltage rises with the constant incoming active power. However, if the incoming active power is controlled to be reduced by the APTC performance of the MVDC system at the same time, the DC-link voltage is expected to be maintained at a constant level. The effectiveness of the suggested APTC application was verified through the PSCAD (power system computer aided design)/EMTDC (electro magnetic transient design and control) simulation.

ACS Style

Sang-Jae Choi; Sung-Hun Lim. Active Power Tracking Control for DC-Link Voltage Suppression of MVDC System with Voltage-Sourced Converter. Journal of Electrical Engineering & Technology 2019, 15, 287 -292.

AMA Style

Sang-Jae Choi, Sung-Hun Lim. Active Power Tracking Control for DC-Link Voltage Suppression of MVDC System with Voltage-Sourced Converter. Journal of Electrical Engineering & Technology. 2019; 15 (1):287-292.

Chicago/Turabian Style

Sang-Jae Choi; Sung-Hun Lim. 2019. "Active Power Tracking Control for DC-Link Voltage Suppression of MVDC System with Voltage-Sourced Converter." Journal of Electrical Engineering & Technology 15, no. 1: 287-292.

Journal article
Published: 18 April 2019 in Energies
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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.

ACS Style

Hyeong-Jin Lee; Sung-Hun Lim; Jae-Chul Kim. Application of a Superconducting Fault Current Limiter to Enhance the Low-Voltage Ride-Through Capability of Wind Turbine Generators. Energies 2019, 12, 1478 .

AMA Style

Hyeong-Jin Lee, Sung-Hun Lim, Jae-Chul Kim. Application of a Superconducting Fault Current Limiter to Enhance the Low-Voltage Ride-Through Capability of Wind Turbine Generators. Energies. 2019; 12 (8):1478.

Chicago/Turabian Style

Hyeong-Jin Lee; Sung-Hun Lim; Jae-Chul Kim. 2019. "Application of a Superconducting Fault Current Limiter to Enhance the Low-Voltage Ride-Through Capability of Wind Turbine Generators." Energies 12, no. 8: 1478.

Journal article
Published: 12 March 2019 in IEEE Transactions on Applied Superconductivity
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To reduce the more increased fault current due to the increase of the power generation with the power demand, the superconducting fault current limiter (SFCL) has received attention as one of the effective methods to resolve the fault current problem. However, the operation of the protection device, especially dependent on the amplitude of the fault current, can be affected by the application of the SFCL. For the protection coordination between the SFCL and the over-current relay (OCR), one of the typical protection devices in the power distribution system, the resetting of operational parameters in the OCRs, which can be troublesome, is required. For these resettings of the protection devices, the fault current calculation from the power distribution system considering the impedance of the SFCL is inevitable. In this paper, the method using the voltage component as the effective parameter of the OCR for the protection of the power distribution system with the SFCL was suggested. Through the analysis on the simulation results from the modeling of the OCR, the suggested method using the voltage component in the OCR could be confirmed to be more effective compared to the previous resetting method of the OCR.

ACS Style

Sung-Hun Lim; Seung-Taek Lim. Analysis on Coordination of Over-Current Relay Using Voltage Component in a Power Distribution System With a SFCL. IEEE Transactions on Applied Superconductivity 2019, 29, 1 -5.

AMA Style

Sung-Hun Lim, Seung-Taek Lim. Analysis on Coordination of Over-Current Relay Using Voltage Component in a Power Distribution System With a SFCL. IEEE Transactions on Applied Superconductivity. 2019; 29 (5):1-5.

Chicago/Turabian Style

Sung-Hun Lim; Seung-Taek Lim. 2019. "Analysis on Coordination of Over-Current Relay Using Voltage Component in a Power Distribution System With a SFCL." IEEE Transactions on Applied Superconductivity 29, no. 5: 1-5.

Regular paper
Published: 06 February 2019 in Transactions on Electrical and Electronic Materials
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Recently, the power system has been changed to introduce the loop power distribution system or the distributed generations for stability and flexibility of power supply. These changes tend to influence on the capacities of protective devices and may cause the malfunctions due to excess of the devices’ capacity. So, as one of the countermeasures of reduction of the fault current, the superconducting fault current limiter (SFCL), has been noticed. However, the reduction of the fault current due to the application of the SFCL in a power distribution system may be able to cause the unexpected malfunctions of the overcurrent relay (OCR). As the OCR, one of the representative protective equipment in a power distribution system, requires the current exceeding the pickup current to be operated, the reduction of the fault current may affect to trip operation of OCR. So, this paper will deal with a trip delay caused by application of the SFCL, which is one of the unexpected malfunctions. To improve OCR’s trip delay, the OCR with voltage component is proposed and the operational characteristics of the OCR with voltage component have been analyzed using the PSCAD/EMTDC in a power distribution system.

ACS Style

Seung-Taek Lim; Sung-Hun Lim. Study on Operational Characteristics of OCR with Voltage Component in a Power Distribution System with SFCL. Transactions on Electrical and Electronic Materials 2019, 20, 118 -123.

AMA Style

Seung-Taek Lim, Sung-Hun Lim. Study on Operational Characteristics of OCR with Voltage Component in a Power Distribution System with SFCL. Transactions on Electrical and Electronic Materials. 2019; 20 (2):118-123.

Chicago/Turabian Style

Seung-Taek Lim; Sung-Hun Lim. 2019. "Study on Operational Characteristics of OCR with Voltage Component in a Power Distribution System with SFCL." Transactions on Electrical and Electronic Materials 20, no. 2: 118-123.