• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1637-1640
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• 2005

This paper presents a technique for electromagnetic field analysis on surge response due to Mid-span back-flashovers effects in lightning protection system of 500 kV EHV single circuit transmission tower by the neural networks method. These analyses are based on modeling lightning return stroke as well as on coupling the electromagnetic fields of the stroke channel to the line. The ground conductivity influences both the electric field as well as the coupling mechanism and hence the magnitude and wave shape of the induced voltage. The technique can be used to analyzed the corona voltage effect, the effective of stroke to the span tower, the surge impedance of transmission lines. The maximum voltage from flashovers effects in the lines. The model is compatible with general electromagnetic transients programs such as the ATP-EMTP. The simulation results show that this study analyses for time-domain with those produced by a cascade multi-section model, the surge impedance of a full-sized tower hit directly by a lightning stroke is discussed.

• 전기학회논문지
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• 제67권8호
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• pp.994-1001
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• 2018

In this paper, to studied about future power system construction using PSS / E-Python API. Python-based future system automatical construction methods and modeling of renewable sources. it confirmed the stability of the powert system for each renewable area by calculating the weighted short circuit ratio (WSCR) index. it calculated the short circuit ratio (SCR) and selected the transmission line linkage scenario to improve the stability of vulnerable areas. it confirmed the WSCR index improvement through the selected transmission line linkage of scenario, and analyzed the stability of the renewable power system applying the scenario. It describes Facts and Shunt devices adjustment for the load flow convergence. It describes the stable methed of the bus voltage through the transformer Ratio Tap adjustment. By performing PSS/E ASCC using the Python it was performed three-phase short circuit fault capacity analysis, it is confirmed whether excess of the fault current circuit breaker capacity. In order to contingency accident analysis, it have described the generation of one or two line list of each areas using the Python. The list is used to contingency analysis and describe the soluted of the transmission line overload through comparison before and after adding the scenario line.

• 조명전기설비학회논문지
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• 제28권6호
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• pp.60-67
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• 2014

Power system fault analysis is commonly based on well-known symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. The majority of fault in transmission lines is unbalanced fault, such as line-to-ground faults, so that both positive and zero sequence impedance is required for fault analysis. When unbalanced fault occurs, zero sequence current flows through earth and ground wires in overhead transmission systems and through cable sheaths and earth in underground transmission systems. Since zero sequence current distribution between cable sheath and earth is dependent on both sheath bondings and grounding configurations, care must be taken to calculate zero sequence impedance of underground cable transmission lines. In this paper, EMTP-based sequence impedance calculation method was described and applied to 345kV cable transmission systems. Calculation results showed that detailed circuit analysis is desirable to avoid possible errors of sequence impedance calculation resulted from various configuration of cable sheath bonding and grounding in underground cable transmission systems.

• 한국전자파학회논문지
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• 제19권7호
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• pp.791-799
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• 2008

본 논문에서는 $DC{\sim}18\;GHz$에서 동작하는 GTEM 셀 설계를 위한 전자파 모델링과 회로망 해석 기법을 제시하였다. GTEM 셀의 동축선 입력 급전부의 모드 변환기, 전송선 길이가 5미터인 확장형 사각 동축선 그리고 전송부 동축선의 전류와 입력단으로부터 입사되는 전자파를 정합시킬 수 있는 종단 부하로 구성되는 3차인 전자파 수치 해석 모델을 제시하였다. GTEM cell의 급전부, 전송선부, 종단 부하부에 대한 등가 회로망 모델을 제시하였으며, 이를 이용하여 전자파 수치 해석 모델에서 구해진 산란 계수로부터 GTEM cell의 성능 평가 지수인 입력 반사 계수를 계산할 수 있도록 하였다. $DC{\sim}18\;GHz$에서 동작하는 $5.0{\times}2.5{\times}1.7\;m$ 크기의 GTEM cell을 설계, 제작, 성능 평가하여 제안한 기법의 효용성을 입증하였다.

• 한국광학회지
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• 제18권4호
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• pp.235-240
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• 2007

본 논문에서는 10 Gbps급 데이터 전송을 위한 CPW(coplanar waveguide) 피드라인(feed-line)을 이용한 세라믹 스템(stem) 기반의 TO 패키지를 제안하였다. 기존의 금속 기반 TO 패키지에서 사용되는 실린더형 피드라인의 주파수 특성과 세라믹 패키지에서 사용되는 CPW 피드라인의 주파수 특성의 차이를 이론적으로 분석 비교하였다. 그리고 이들 패키지에 DFB 레이저다이오드(laser diode: LD)를 실장하여 측정된 3 dB 주파수 대역폭은 각각 3.5 GHz와 7.8 GHz로 사용된 패키지에 따라 큰 차이를 갖는 것을 밝혔다. 이러한 측정결과는 등가회로를 이용한 이론적인 계산결과와 잘 일치함도 확인하였다. 이상의 결과를 바탕으로 LD 광모듈의 주파수 특성을 개선하기 위한 방안으로 세라믹 재질의 비전도성 유전체를 스템으로 이용한 세라믹 스템 기반의 CPW 피드라인을 장착한 새로운 TO 패키지를 제안하였다. 제안된 패키지는 HFSS(high frequency structure simulator)를 이용하여 추출된 S 파라미터 값으로부터 기존의 금속 기반의 TO 패키지보다 월등히 넓은 주파수 특성을 얻을 수 있다는 것을 알 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.128-133
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• 2003

In this paper, we have proposed a method by using virtual simulation to calculate the behaviors of spacers to avoid conductor galloping with the hanging composite polymer spacer between conductors on different phases. We have considered with three types of modeling considerations for the analysis of galloping in power transmission lines, such as iced-single conductors without spacer, iced-single conductors with spacers, and iced-two bundle conductors with spacers. In simulation, the finite element method is used to calculate the structural response with geometric nonlinear behavior. The iced conductor is modeled by two beam-element faces with which it is connected. The ANSYS program is applied too. First, the calculation results show that the two beam-element model is very suitable to make a virtual simulation. Second, the amplitude of conductor galloping is reduced after hanged spacers. Third, when number of spacer is increased, the maximum magnitude of natural frequency of iced conductor will reduce. Final, the behaviors of spacers are verified in viewpoint of standard cases.

• 전자공학회논문지D
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• 제36D권1호
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• pp.1-7
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• 1999

본 논문에서는 마이크로 스트립 다중 전송 선로의 고속 디지털 펄스 신호에 대한 상호 결합 특성을 시간영역에서 해석하기 위해 FDTD법을 사용하였고, SPICE에 의한 결과 및 측정결과와 상호 비교하였다. 기존 SPICE에 의한 다중 전송 선로의 해석은 FDTD법에 비해 정확도가 저하되고, 손실 특성에 대한 해석을 할 수 없으므로, 본 논문에서는 FDTD법을 이용하여 무손실 및 손실을 고려한 다중 전송 선로의 디지털 전송 특성을 해석하고 누화 특성을 비교하여 나타냈다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• Journal of Power Electronics
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• 제10권1호
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• pp.85-90
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• 2010

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

• 한국통신학회논문지
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• 제24권8B호
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• pp.1593-1600
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• 1999

본 논문은 적외선 유도 무기의 표적 추적 시뮬레이션을 위한 공중 표적 추적 모델링에 대한 연구이다. 표적의 적외선 특성, 대기 투과 특성, 및 검출기 특성에 대한 모델링이 핵심 기술을 이루는 이 모델링은 시선, 거리, 및 대기 상태에 따른 다양한 추적 조건에서 공중 표적을 포착하는 과정을 보여준다. 계산된 결과를 측정값과 비교하거나 제안된 모델링을 적외선 표적 추적에 관련된 여러 시뮬레이션들에 적용하여 그 효용성을 확인하였다. 또한, 제안된 모델링은 유사 표적으로부터 표적만을 효과적으로 찾아내기 위한 최적 검출기 및 검출 대역 설정을 위한 이정표로 활용될 수 있다.