• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.5
• /
• pp.22-28
• /
• 2003

This paper describes the frequency dependence of the grounding impedance. In order to propose the evaluation method of the transient response of powered grounding systems, the grounding impedances were measured with varying the frequency of incoming currents by way of the variable frequency inverter and band pass filter. The magnitude and phase of the grounding impedance were analyzed in the frequency range of 20 [Hz]∼2.1[kHz]. The grounding impedance were increased with increasing the frequency of the test current. The grounding impedance at the frequency of 2[kHz] in the actual 22.9[kV] substation grounding system was approximately 3 times as large as the 60[Hz] grounding impedance. It was found that the frequency dependence of the grounding impedance is mainly subject to the inductive reactance of the grounding conductors. As a result, it is critical to determine the shape and size of grounding grid reducing the resultant inductance in grounding systems for lightning surge protection.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.5
• /
• pp.857-862
• /
• 2008

This paper evaluate the performance using a simulated 490KHz narrow band filter based on characteristic parameters appropriately extracted from 490KHz band-pass filter after considering each characteristic, which is modeled on equivalent circuit and applied to NAVTEX receiver using crystal oscillator. The evaluation results show that the value of a series capacitor of crystal oscillator has only little capacity by Cs=21.094fF and the bandwidth characteristics of filter go worse as the capacity value of crystal oscillator grow increase. Moreover, the series inductance value of crystal oscillator has a relatively big value by L=5H, therefore the bandwidth characteristic according as inductance's capacity shows more little effect than the capacity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.6
• /
• pp.18-25
• /
• 2000

This paper describes the design and fabrication of a home-panel board for electromagnetic compatibility which can protect home-electric appliances from transient voltages and power line noise. The proposed panel board include a transient voltage blocking device and a EMI filter which consisted of varistors, capacitors, and bus line inductance.A performance test of the prototype panel board, blocking characteristics to transient voltages and reduction characteristics to power line noise, are carried out by using a combination surge generator standardized in IEC and a network analyzer.The results showed that the proposed panel board is satisfied with the surge immunity level of IEC 61000-4-5, and has an over 20[dB] noise reduction performance in ranges from 150[kHz]∼30[MHz].

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.1
• /
• pp.92-99
• /
• 2002

Transient in an electric distribution system are mainly generated by switching. This paper presents analysis of switching surge and means of limiting the voltage magnification transient for high voltage power systems by using the EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor contraction capacitor banks to harmonics filters. An inductance in series with the capacitor bank was used to decrease the transient voltage at the customer bus to acceptable levels. And also simulation results used the EDSA harmonics analysis program show the effect of harmonics reduction.

• Proceedings of the KIPE Conference
• /
• 2019.07a
• /
• pp.251-253
• /
• 2019

본 논문은 1.8kW (4.5kV, 450mA)출력의 마그네트론을 구동하기 위한 2.5kW (5kV, 0.5A) 고전압 DC 전원장치 설계에 대해 기술한다. 무선 전력 전송을 위한 위상배열 시스템에 이용되는 마그네트론의 경우 인가되는 전압의 리플 최소화는 필수적이다. 본 논문에서는 소프트 스위칭을 기반으로한 400kHz 이상의 스위칭 주파수로 컨버터를 설계함으로써 출력리플을 저감하고 필터성분을 최소화 하여 전력밀도를 높일 수 있도록 한다. 변압기의 누설인덕턴스 만을 이용하여 공진 인덕터를 구현하고 변압기의 기생 커패시터 성분과 직렬로 스택킹 된 출력 정류 다이오드의 전압 밸런싱을 위한 커패시터를 병렬 공진 커패시터로 활용한 LCC 공진형 컨버터 고밀도 설계에 대하여 기술한다. 또한, 공진전류의 Trapezoidal 해석 및 설계를 통해 도전 손실을 줄일 수 있는 LCC공진형 컨버터 기반의 마그네트론 구동전원 설계에 대하여 상세 기술하고 PSpice를 이용한 Simulation 및 실험 결과를 통하여 개발된 전원의 우수성을 검증한다.

• Journal of IKEEE
• /
• v.23 no.3
• /
• pp.1046-1053
• /
• 2019

In a multi-channel single-ended system, the far-end crosstalk (FEXT) due to mutual inductance and mutual capacitance between two adjacent channels critically limit the bandwidth. FEXT causes crosstalk-induced jitter (CIJ) and crosstalk-induced glitch (CIG) which leads to timing margin and voltage margin degradations, respectively. Therefore, FEXT must be compensated in order to increase eye opening and achieve high data-rate. It can be compensated in transmitter by controlling the timing of the data or reshaping the waveform of the signal. Also, FEXT can be compensated in receiver by generating mimicked FEXT using high-pass filter. In this paper, recent techniques to compensate FEXT are investigated, with discussions of their pros and cons.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.5
• /
• pp.10-24
• /
• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch $S_5\;and\;S_6$ in the secondary switch which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household