• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.388-390
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• 2008

This paper discusses the effect according to the change of grounding system modeling in substation. Substation grounding system is modelled by CDEGS and EMTP. Node voltages of grounding system is variously analysed by 3 grounding cases and 4 kinds of transient frequency ranges. The results of this paper will contribute to advance the grounding system modeling of substation in the range of high frequency transient such as lightning surge.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.35-40
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• 2007

The one step type and two step type pole are used in distribution line. If the three phases are not balanced, the communication line can be damaged by induced voltage. This paper calculates the neutral current using KEPCO's distribution system model which is only composed by one step type pole. The used system model is modelled by using ATPDraw and the neutral current is calculated by using EMTP/MODELS. Many cases for abstracting the neutral current characteristics in KEPCO's distribution system are simulated and analyzed.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.104-110
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• 2004

This paper describes the lightning overvoltage occurred differently according to installation methods of arresters and overhead grounding wire in case of double circuits distribution systems. First, the analysis models are established considering the severe case between upper and lower distribution line, when the direct lightning surge strikes to the overhead grounding wire. The lightning overvoltage is variously analyzed with the change of grounding interval and resistance, arrester installation interval as well as the magnitude of surge using EMTP. After simulation results are compared with the BIL which is now used at field, the authors propose the methods for suitable shielding in domestic distribution systems.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.173-174
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• 2008

Wavelet transform is a new method for power system analysis. On the basis of extensive investigation, optimal mother wavelets for the detection of leakage current are chosen. The recommended mother wavelet is 'Daubechies 4' wavelet. This paper proposes a technique for modeling toe finding point of leakage current in distribution system using wavelet transform and EMTP MODELS.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.379-380
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• 2008

For proper application and operation of a SFCL(Superconducting Fault Current Limiter), the prior investigation of fundamental characteristics and its effects to the distribution systems are needed. In this paper, the resistive type SFCL and recloser were developed by using EMTP/ATPDraw and MODELS language. To analyze the effect of recovery characteristics of SFCL according to recloser operation in distribution systems, case studies have been simulated and investigated.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.381-382
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• 2008

This paper presents a novel scheme for reducing an asymmetry current with SFCL (Superconducting Fault Current Limiter) operation during transient period, when a fault occurs in power systems. The main idea is installation an auxiliary SFCL with characteristics, which reduces the asymmetry fault current in first half cycle before the operating of main SFCL. For proper activities of SFCLs, the principle of asymmetry current nature is reviewed. A scheme of asymmetry components reduction with SFCL is then explained. The EMTP/ATPDraw model of SFCLs using MODELS language developed and simulated to verify the performance and effectiveness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.7
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• pp.1135-1140
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• 2008

Superconducting fault current limiters (SFCL) have been progressing due to the development of superconducting technology. The resistor type SFCL is one of the promising current limiting devices in power system for its effective operation. For proper application and operation of a SFCL, the prior investigation of fundamental characteristics and its effects to the distribution systems are needed. The most important current limiting behavior of a SFCL is dominated by quenching and recovery characteristics. In this paper, the resistive type SFCL was developed by using EMTP/ATPDraw and MODELS language. The operating characteristics and current limiting behaviors of the SFCL in distribution systems have been simulated and investigated.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2069-2072
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• 1999

The extended 765 kV system may have severe electrical transients according to the interconnection of transmission lines and have long transmission line over 250 km. So we need to analyze the transient phenomena to confirm the insulation coordination which is designed for 765 kV project step I. In particular, this paper shows the analysis results of secondary arc extinction by HSGS (high speed ground switch) application. The EMTP/MODELS were used to simulation study of secondary arc phenomena. We had confirmed the TRV(transient recovery voltage) and rated current of HSGS which will be used in the KEPCO 765 kV system.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.763-765
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• 1998

Flicker embrace all diverse effects of rapid voltage fluctuation. To minimize these effects, the voltage fluctuation must be kept below the limit. The aim of this study is to simulate TCR for flicker suppression. To do this, we built models similar to electrical systems of fields using EMTP and attached TCR to them. After attaching TCR, we confirmed reduction of incoming voltage fluctuation and reactive power compensation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.698-704
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• 2003

Autoreclosure provides a mean of improving power transmitting ability and system stability. The conventional reclosure adopts the fixed dead time interval strategy, that is, the reclosure is activated after a time delay to restore the system to normal as quickly as possible without regard to the system conditions, however, these simple techniques cannot give the optimal operating performance. For this reason, various adaptive reclosure algorithms have been proposed recently, This paper presents an adaptive autoreclosure algorithm including the variable dead time, optimal reclosure, sequential reclosure and emergency extended equal-area criterion (EEAC) algorithm in order to improve the system stability. The reclosure algorithm performs out the operations that are attuned to the power system conditions. The proposed adaptive reclosure algorithm is verified and tested by using EMTP MODELS, and the simulation results show that the system oscillations are reduced and the transient stability is enhanced by employing the proposed adaptive reclosure algorithm.