• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.148-152
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• 2010

The superconducting fault current limiter (SFCL) applied into the neural line of a power system, which can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault, was reported to be the effective application location of the SFCL in a power system. However, the limiting operation for the symmetrical fault current like the triple line-ground fault is not effective because of properties of the balanced three-phase system. In this paper, the limiting method of the symmetrical fault current in a power system with a SFCL applied into neutral line was suggested. Through the short-circuit experiments of the three-phase fault types for the suggested method, the fault current limiting and recovery characteristics of the SFCL in the neutral line were analyzed and the effectiveness of the suggested method was described.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.37-44
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• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.289-289
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• 2008

We investigated the operational characteristics of the separated three-phase flux-lock type superconducting fault current limiter (SFCL). The single-phase lock type SFCL consist of two coils, which are wound in parallel through an iron core. The high-$T_c$ superconducting(HSTC) thin film connected in series with secondary coil. The separated three-phase flux-lock type SFCL consist of three single-phase flux-lock type SFCL. In a normal condition, the SFCL is not operate. When a fault occurs, the current of a HSTC thin film exceeds its critical current by fault current, the resistance of the HSTC thin film generated. Therefore fault current was limited by SFCL. The separated three-phase flux-lock type SFCL are operated in fault condition such as the the single line-to-ground fault, the double line-to-ground fault and the triple line-to-ground fault. The experimental results, the SFCL operational characteristics was dependent on fault condition.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.97-100
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• 2004

This paper introduced an artificial fault generator which was operated in the Go-Chang field-test center and explained the result of single line-to-ground fault by AFG. The AFG can basically experiment line-to-line and line-to-ground faults. This facility directly connected distribution transmission lines, so the test results are very useful for power system analysis and protection. Using the function of the AFG, we briefly said the test methods ud results for the 22.9[kV-v] and $6.6[kV-{\Delta}]$ system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.54-56
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• 2005

In this paper, we investigated the quench characteristics of HTSC elements in the integrated three-phase flux-lock type SFCL according to fault types such as the single-line-to-ground fault, the double-line-to-ground fault, the line-to-line fault and the three-line-to-ground fault. The integrated three-phase flux-lock type SFCL was the upgrade version of the single-phase flux-lock type SFCL. The structure of the integrated three-phase flux-lock type SFCL consisted of three-phase flux-lock reactor wound on an iron core with the ratio of the same turn between coil 1 and coil 2 in each phase. When the SFCL is operated under the normal condition, the flux generated in the iron core is zero because the flux generated between two coils of each single phase is canceled out. Therefore, the SFCL's impedance is zero, and the SFCL has negligible influence on the power system. However, if a fault occurs in any single-phase among three phases, the flux generated in the iron core is not zero any more. The flux makes HTSC elements of all phases quench irrespective of the fault type, which reduces the current of fault phase as well as the current of sound phase. It was observed that the fault current limiting characteristics of the suggested SFCL were dependent on the quench characteristics of HTSC elements in all three phases.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1807-1813
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• 2018

In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.960-962
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• 2005

In this paper, we investigated the quench characteristics of high-Tc superconducting(HTSC) elements in the integrated three-phase flux-lock type superconducting fault current limiter(SFCL) according to fault types such as the single-line-to-ground fault, the double-line-to-ground fault, the line-to-line fault and the triple-line-to-ground fault. The integrated three-phase flux-lock type SFCL is an upgrade version of single-phase flux-lock type SFCL. The structure of the integrated three-phase flux-lock type SFCL consisted of a three-phase flux-lock reactor wound on an iron core with the ratio of the same turn between coil 1 and coil 2 in each phase. When the SFCL is under the normal condition, the flux generated in the iron core is zero because the flux generated between two coils of each single phase is canceled out. Therefore, the SFCL's impedance is zero, and the SFCL has negligible influence on the power system. However, if a fault occurs in any single one of three phases, the flux generated in the iron core is not zero any more. The flux makes HTSC elements of all phases to quench irrespective of the fault type, which reduces the current in fault phase as well as the current of sound phase. It was obtained that the fault current limiting characteristics of the suggested SFCL were dependent on the quench characteristics of HTSC elements in all three phases.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.470-471
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• 2008

SVL is installed at underground transmission system to protect cables and insulation joint-box from overvoltages caused by lightning, switching, and line-to-ground fault. Domestic underground power system adopts cross bonding type to reduce the induced voltage at sheath, but single-point bonding is required depending the system installation configuration. SVL can be easily broken by overvoltages induced at joint-box because single-point bonding has uneffective system structure to extract fault current. ANSI/IEEE recommends Parallel Ground Continuity Conductor(PGCC) to prevent SVL breakdown. In this paper, EMTP simulation is performed to analyze effects on SVL under PGCC installation when single-line-to-ground fault occurs. The result shows that PGCC and short single-point bonding distance can reduce overvoltages at SVL.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.1-7
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• 2011

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.39-40
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• 2007

The analysis of fault current limiting characteristics according to variation of fault current level in the integrated three-phase flux-lock type superconducting fault current limiter (SFCL), which consisted of three-phase flux-lock reactor wound on an iron core with the same turn's ratio between coil 1 and coil 2 for each single phase, was performed. To analyze the current limiting characteristics of this integrated three-phase flux-lock type SFCL, the short circuit experiments was carried out the various three-phase faults such as the single line-to-ground fault, the double line-to-ground fault, the triple line-to-ground fault. From the experimental results, the fault current limiting characteristic was improved according to increase of fault current level.