• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.1
• /
• pp.54-57
• /
• 2001

We have developed a new multidomain vertical-alignment (MVA) mode using a homeotropic photopolymer that provides a wider viewing angle for nematic liquidcrystal (NLC) with negative dielectric anisotropy. Good voltage-transmittance curves for he new MVA cell using the homeotropic photopolymer were observed. The viewing angle of the new MVA cell using the homeotropic photopolymer was wider than that of the conventional VA cell. The wide viewing angle using the new MVA cell is attributable to 4-domain by the ribs with UV exposure on the photopolymer.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.524-525
• /
• 2013

(주)효성에서는 FACTS(Flexible AC Transmission System) 기기 중 하나인 1 MVA STATCOM(Static synchronous Compensator)을 개발하여 제주 행원의 풍력단지에 설치하였으며, 이에 대한 실증운전 및 시험을 완료하였다. STATCOM은 연계된 전력계통의 상황에 맞게 일정전압 제어 및 무효전력 제어모드로 운전되며, 이를 이용하여 계통전압의 안정화에 기여함으로써 전력품질을 향상시키는 역할을 한다. 본 논문에서는 1 MVA STATCOM의 실증운전을 통해 전력품 질향상 사례를 분석하였다.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1003-1005
• /
• 2003

In this paper, 3-D nonlinear electromagnetic analysis of a single phase 1MVA 22.9 kV/6.6 kV high temperature superconducting(HTS) transformer with double pancake windings was accomplished. The characteristics of 1MVA HTS transformer such as The efficiency, voltage regulation and % impedance voltage drop were obtained by the 3-D non-linear electromagnetic analysis. And in order to verify the 3-D non-linear electromagnetic analysis of a single phase 1MVA HTS transformer, a 1MVA test transformer with windings made of copper tapes with the same size as BSCCO-2223 HTS tape was manufactured. The energy conservation method to perform the analysis of leakage impedances of both a 1MVA HTS transformer and test transformer was used. The characteristic analysis such as efficiency, voltage regulation and % impedance voltage drop of transformer was performed. And the obtained values of both 1MVA HTS transformer and test transformer were compared.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.200-202
• /
• 2003

In this paper, 3-D electromagnetic analysis of a single phase 1MVA 22.9kV/6.6kV High Temperature Superconducting(HTS) transformer with double pancake windings by using the OPERA 3D was accomplished. And in order to perform the analysis of leakage impedances of a 1MVA HTS transformer, the energy conservation method was used. The efficiency voltage regulation and ％ impedance voltage drop of a 1MVA HTS transformer were obtained by the analysis of leakage impedances.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.160-161
• /
• 2012

(주)효성에서 자체 설계 및 개발한 FACTS(Flexible ACTransmission System) 기기중 하나인 1 MVA STATCOM(Static synchronous Compensator)은 전압 안정도 개선 및 역률제어를 통해 계통전력품질을 향상시킨다. 현재 개발된 1 MVA STATCOM은 제주 행원 풍력단지 내 풍력 발전기 14호기가 연계된 22.9 kV 계통에 병렬접속 되어있으며 현재 실증 운전 중에 있다. 본 논문에서는 1 MVA STATCOM의 설치 및 실증 운전사례를 소개한다.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.1
• /
• pp.72-84
• /
• 2017

This study aimed to suggest a method to establish vessel-lumen-area chronologies in domestic Quercus spp. from Mt. Songni and to verify their potential as a climate proxy. In order to establish vessel-lumen-area chronologies, three options were applied to filter vessels. Options 1 and 2 use vessels having lumina larger than or equal to $6,000{\mu}m^2$ (MVA-60) and $7,500{\mu}m^2$ (MVA-75), respectively, to establish the chronologies by their mean values in each year, and option 3 uses the largest one (MAX) in each tree ring. MVA-60 and MVA-75 had mostly significant relationships with the winter precipitation between November in the previous year and January in the current year, however, MAX had only significant relationship with November precipitation in the previous year. Based on these results, it was verified that the potential of vessel lumina in domestic Quercus spp. could be a climate proxy in dendroclimatology.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.259-262
• /
• 2001

본 논문은 2003년 한전 실계통(154kV 강진 S/S)에 적용예정인 80MVA UPFC(Unified Power Flow Controller)시스템의 동적특성을 EMTDC/PSCAD를 이용하여 분석한 결과이다. UPFC는 FACTS 기기중 전압, 임피던스, 위상각등 전력전송 제어를 위한 송전선로의 모든 파라미터를 동시에 독립적으로 제어 할 수 있는 FACTS기기[1]로서, 미국 Inez S/S, Marcy S/S에 이어 강진 S/S에 80MVA 용량의 UPFC가 실계통 적용될 예정이다. 본 논문은 과도현상 해석 프로그램인 PSCAD/EMTDC를 이용하여 80MVA UPFC 제어기와 적용 대상 계통인 강진 S/S 인근 계통을 모델링하고 상정사고에 대한 UPFC 제어효과 분석에 대하여 기술하였다. 적용된 EMTDC UPFC모델은 실제 80MVA UPFC 기기에 채용된 전력회로, 제어기, 보호시스템과 동일하게 모델링하였으며 적용 대상계통은 PSS/E 해석결과와 동일하도록 강진 S/S인근 계통을 축약 등가화한 계통모델을 사용하였다.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.93-96
• /
• 2001

본 논문은 2003년 한전 실계통(154kV 강진 S/S)에 적용예정인 80MVA UPFC(Unified Power Flow Controller) 시스템의 적용효과를 EMTDC/PSCAD 프로그램을 이용하여 분석한 결과이다. UPFC는 현재까지 개발된 FACTS 기기중 전압, 임피던스, 위상각등 전력전송 제어를 위한 송전선로의 모든 파라미터를 동시에 제어 할 수 있는 유일한 FACTS기기[1]로서 미국 Inez S/S에 이어 세계 두번째로 강진 S/S에 80MVA 용량의 UPFC가 실계통 적용될 예정이다. 본 논문은 대표적인 과도현상 해석프로그램인 EMTDC를 이용한 80MVA UPFC의 적용시 계통 제어효과 분석에 대하여 기술하였다. 적용된 EMTDC UPFC모델은 실제 80MVA UPFC 기기 전력회로, 제어기와 동일하게 모델링하였으며 적용 대상계통은 한전 계통 데이터를 바탕으로 강진 S/S인근 계통을 축약 등가화한 계통모델을 사용하였다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.41-44
• /
• 2003

We manufactured double pancake type windings with BSCCO wire for 1MVA HTS transformer. To verify cracks of HTS wire and performance of manufactured windings, the transportation current was measured. In this paper, we present result of the transportation current test as a DC current and compare a drop of current performance of HTS wire due to tension and rounding during the manufacturing with technical data. We obtained good results and this will be useful for another manufacturing of HTS winding

• Proceedings of the KIEE Conference
• /
• 2008.11a
• /
• pp.98-100
• /
• 2008

This study proposes a model of 1.5MVA wind power system in Go-chang field demonstration and performs simulation according to variable wind speed. 1.5MVA wind power system was verified by computer simulations with PSCAD/EMTDC software. Terminal voltage, grid voltage and active/reactive power can be observed through the simulation results.