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이성두(Seong-Doo Lee) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.9월
This paper gives a estimation of the conversion of AC transmission line to DC line. Transmission line conductors are suitable for either ac or dc operation, their current rating being very nearly the same for each since heating is approximately the same for one rms AC ampere as one continuous DC ampere. This paper show the result that DC transmission can be alternative to increase transmission capacity.
이성두(Seong-doo Lee),김찬기(Chan-ki Kim) 대한전기학회 2010 전기학회논문지 Vol.59 No.10
The HVDC system consists of ac side and dc side through thyristor valve. ac side protection is similar to conventional ac system protection schemes but dc side protection is different from ac side of HVDC system. AC system don't have controller but HVDC system has controller that controls and protects system from faults and disturbance. This paper show protectional function of HVDC dc side such as asymmetry protection, ac/dc differential protection, dc overvoltage, dc overcurrent protection. Protection models is developed using RTDS software and assessment of protection models is also performed by RTDS system.
HVDC시스템 적용을 위한 Triple-tuned 필터 설계방법 연구
이성두(Seong-Doo Lee),최순호(Soon-Ho Choi),김찬기(Chan-Ki Kim),차한주(HanJu Cha) 대한전기학회 2015 전기학회논문지 Vol.64 No.9
The ac side current of a line commutated converter(LCC) high voltage direct current (HVDC) is characterized by highly non-sinusoidal waveform. If the harmonic current is allowed to flow in the connected ac network, it may cause unacceptable levels of distortion. Therefore, ac side filters are required as part of the total HVDC converter station, in order to reduce the harmonic distortion of the ac side current and voltage to acceptably low levels. The ac filters are also employed to compensate the requested reactive power because LCC HVDC also consume substantial reactive power. Among different types of filters, triple-tuned filters have been widely utilized for HVDC system. This paper presents two design methods of triple-tuned filter; equivalent method and parametric method. Using a parametric method, in particular this paper proposes a design algorithm for a triple tuned filter. Finally, the performance of the design algorithm is evaluated for a 250kV HVDC system in Jeju island. The results cleary demonstrate the effectiveness of proposed design method in harmonics reduction.
HVDC시스템을 위한 Double Tuned Filter설계
이성두(Seong-Doo Lee),김재한(Jae Han Kim) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.9월
This paper gives a parameter calculation method of double tuned filter for HVDC system Double tuned filter has two capacitors and two reactors and consists of series loop and parallel loop. First of all the algorithm of the parameters of the single tuned filter are presented. Another way of double and triple tuned filter design, which is based on the analysis of circuits and impedance frequency characteristics of AC filters, is introduced.
이성두(Seong-Doo Lee) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.12
HVDC converter station consists of a number of equipment such as converter transformer, ac filter, thyristor valve and so on. They can be acoustic noise sources. In this paper, we analyzed the simulation results of the outdoor acoustic noise for HVDC converter station. It shows that maximum noise level in boundary of HVDC converter station exceeds regulation value. The main factors in generating maximum noise level are ac filter and converter transformer. Then we applied some soundproof countermeasures in HVDC converter station. Shielding wall is enough to reduce transformer noise level but not enough to reduce ac filter noise level. In case of ac filter, soundproof building is effective in satisfying noise level regulation in boundary of HVDC converter station. In addition, we also studied effects of season, soundproof woods, ground.
이성두(Seong-Doo Lee) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.9월
This paper gives a basic concept of asymmetry protection for HVDC system. The Asymmetry protection has functions that detect 60㎐/120㎐ components due to misfiring or commutation failure and protect HVDC system from overvoltage and overcurrent. The Asymmetry protection model consists of band-pass filter, RMS calculator, level detect, integrator, comparator. This paper shows model's configuration and operating characteristics.
PSCAD/EMTDC를 이용한 ±35kV급 MVDC 하이브리드 배전망의 사고해석에 관한 연구
강성현(Seong-Hyun Kang),이후동(Hu-Dong Lee),이성두(Seong-Doo Lee),노대석(Dae-Seok Rho) 대한전기학회 2021 전기학회논문지 Vol.70 No.8
Based on ±35kV-scale MVDC hybrid distribution system to demonstrate MVDC distribution technology, this paper presents scenarios of contingency fault analysis and modeling for impact evaluation on MVDC hybrid distribution system in order to examine the operation characteristics of MVDC facilities and customers. And also, this paper proposes a modeling of the ±35kV-scale MVDC hybrid distribution system using PSCAD/EMTDC, which is composed of distribution substation, MVDC distribution feeder, converter station and PV system. From the simulation results of fault analysis in MVDC distribution system based on the modeling for impact evaluation on distribution system with the fault scenarios, it is confirmed that tremendous fault current can be momentarily occurred due to discharging of DC link capacitor in converter station regardless of fault type. Furthermore, it is found that the faults in MVDC feeder can cause the phenomenon of under-voltage at customers in other feeder of the main transformer. In addition, it is clear that the malfunction of recloser in other feeder can be prevented due to ungrounded system of MVDC system, and also the voltages of AC 22.9kV bus and MVDC feeder are maintained in a stable manner even if ground fault is occurred in AC 22.9kV feeder.