• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.225_226
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• 2009

최근 전력산업의 화두가 되고 있는 지능형 전력망과 그린 에너지 사용의 확대로 인하여 배전계통은 더욱 복잡한 망구조를 띄고 있으며, 이에 따라 계통에서 발생하는 고장전류 증가 및 과도현상들도 매우 다양하게 나타나고 있다. 이와 같은 과도현상으로부터 배전계통을 보호하기 위해 전력용 퓨즈, Recloser, 과전류 계전기, 과전압 계전기 등이 사용된다. 이러한 보호 기기들이 정상 동작하기 위해서는 사전 모의를 통해 상시 부하 전류와 고장 전류 및 계통 이상 상태를 파악하고, 다른 보호기기와의 보호 협조를 고려해야 한다. 이러한 보호 장비들을 구현하고, 동작을 검증함에 있어 기존에는 EMTP(ElectroMagnetic Transients Program)와 같은 과도현상 해석 프로그램이 사용되어 왔다. 최근 상용 버전으로 개발된 EMTP-RV(ElectroMagnetic Transients Program-Restructured Version)는 기존의 컨트롤 소자들로만 구현해야 했던 한계점을 극복하기 위해 사용자 정의가 가능한 DLL(Dynamic Link Library) 기능을 제공함으로써 사용자가 EMTP-RV 개발자와 동일한 환경 하에서 계통 소자를 구현할 수 있도록 하였다. 본 논문에서는 새로운 모델링 기법인 DLL 기능을 이용하여 과전압계전기를 구현하고 결과를 검증하여 모델링 방법의 적합함을 보였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.82-93
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• 2006

In this paper, filters are designed to reduce transients overvoltage in inverter fed high-voltage large-capacity induction motor drive system. Design issues for a LCR filter at the inverter output terminals to reduce the dv/dt of the inverter output pulse and a RC filter at the induction motor input terminals to match the characteristic impedance between cable and induction motor are examined in detail. These filters are modeled to be suitable to high-voltage large-capacity induction motor. The performance of the filter is evaluated through simulation using EMTP(ElectroMagnetic Transients Program). We presented filters that used high voltage large-capacity induction Motor on the basis of this. Effect of the filter is analyzed for variation of the cable length. Characteristics of filters are analyzed to reduce harmonic in voltage waveform of induction motor input terminal. The switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. Filter for to mitigate transients overvoltage presents a required component in drive system of high-voltage large-capacity induction motor. Also, proposed filters are proved through simulation using EMTP.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.37-46
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• 2015

In order to charge EVs, they have to be connected to distribution system. Therefore, if unprecedented numbers of EVs are connected to power systems, it could result in deterioration of power quality, overload, and other system problems. In this paper, the effects of voltage sag on the distribution system due to the connection of EVs is evaluated by considering related field data of Republic of Korea such as the number of gasoline-fueled vehicles, seasonal load of power system and the monthly and daily real-time traffic volume. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP).

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.297-303
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• 2012

This paper presents the simulation results for the analysis of a lightning surge, switching transients and very fast transients within a thermal plant. The modeling of gas insulated substations (GIS) makes use of electrical equivalent circuits that are composed of lumped elements and distributed parameter lines. The system model also includes some generators, transformers, and low voltage circuits such as 24V DC rectifiers and control circuits. This paper shows the simulation results, via EMTP (Electro-Magnetic Transients Program), for three overvoltage types, such as transient overvoltages, switching transients, very fast transients and a lightning surge.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.10
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• pp.56-62
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• 2014

When fault currents contain decaying DC offset, the peak value of the fault current in the first cycle of the fault period is higher than the fault current during the steady-state period. To reduce the asymmetric fault current, this paper proposes an operation scheme using the series connection of two hybrid type Superconducting Fault Current Limiters (SFCLs) : an auxiliary SFCL and a main SFCL. The proposed method calculates the fault angle by comparing the zero-crossing time with fault detection time. According to the fault angle calculated, an auxiliary SFCL operates to reduce an asymmetric fault current during half a cycle after fault occurrence. After this process, the fault current is limited by a main SFCL. To confirm the usefulness of the proposed method, case studies using Electro-Magnetic Transients Program (EMTP)/Alternative Transient Program (ATP) Draw are perfomed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1720-1725
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• 2008

Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1789-1797
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• 2017

It is necessary to charge electric vehicles in order to drive them. Thus, it is essential to have electric vehicle charging facilities in place. In the case of a household battery charger, the power similar to that consumed by a household with a basic contract power of 3kW is consumed. In addition, many consumers who own an electric vehicle will charge their vehicles at the same time. The simultaneous charging of electric vehicles will cause the load to increase, which then will lead to the imbalance of supply and demand in the distribution system. Thus, a smart charging scheme for electric vehicles is an essential element. In this paper, simulated conditions were set up using real data relating to Korea in order to design a smart charging technique suitable for the actual situation. The simulated conditions were used to present a smart charging technique for electric vehicles that disperses electric vehicles being charged simultaneously. The EVs and Smart Charging Technique are modeled using the Electro Magnetic Transients Program (EMTP).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1065-1070
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• 2009

This paper presents the new technique of modeling using Dynamic Link Library(DLL) in ElectroMagnetic Transients Program - Restructured Version(EMTP-RV) in which we have simplified the procedures of OverCurrent Relay(OCR) modeling. The DLL function is designed to allow EMTP-RV users to develop advanced program model modules and interface them directly and intimately with the EMTP-RV engine. The modeled OCR is verified by simulating the various fault cases in the distribution system. Also, the performance for the modeling of OCR using DLL is compared with that of the method using the control components of EMTP-RV and using EMTP/MODELS. The results show the validity of modeled OCR and the effectiveness of the method using DLL function.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.873-878
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• 2009

When the transmission lines are initially energized for power system restoration, the power system suffers the various overvoltages that can be classified as steady-state, transient, and dynamic overvoltages. For the accurate analyses of these overvoltages, many researchers utilize different simulation tools such as Power System Simulator for Engineering(PSS/E). Although PSS/E provides good solutions in steady-state and dynamic overvoltages, it is not suitable for transient overvoltages. Therefore, transient overvoltages are simulated by using Electro-Magnetic Transients Program(EMTP) developed for the analysis of transients in the power system. Recently, EMTP can be also used to simulate dynamic behavior of the system. In order to analyze the transient overvoltages with steady-state and dynamic overvoltages, the authors adopt EMTP as the simulation tool for the analysis of overvoltages. This paper presents the simulation results for the analyses of various overvoltages, and the possibility of EMTP to be used for these types of analyses.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.33-41
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• 2010

There are several overvoltages by abnormal conditions in power system. We need to calculate these ovevoltages for the insulation design and the fault analysis. For these calculations, we used EMTP(Electro-magnetic Transients Program). During EMTP calculations, the accurate modelling of the equipments is very important for analysis results. In this paper, we considered the effects of the modelling condition's changes for transmission line within EMTP modelling cases of overvoltage analysis. Specially, we considered CB closing cases of 765[kV] system. So, we had changed the calculation frequencies of Line Constants, which is used for CB closing cases. In addition, we compared the calculation result and the measured result.