• Title/Summary/Keyword: Black voltage

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A study on the investigation and the verification method of the regional restorative transmission (지역별 시송전선로 검토 및 검증방안에 관한 연구)

  • Lee, Nam-Ho;Song, In-Jun;Cho, Kyeong-Bo;Kwak, No-Hong
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.187-189
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    • 2003
  • Service restoration following a complete or partial collapse starts with reenergizing a transmission line from black-start generators. Voltage problems can arise from Ferranti effect as unloaded transmission line is reenergized and has to be required to consider it when KPX makes a restorative plan on the massive blackout. This paper presents the investigation of seven regional blackstart lines which are chosen by KPX restorative plan and suggests the verification method for the new designed line according to the system modification.

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Using the Multi-Excitation method, the high voltage SMPS design (다중 여자 방식의 고압 SMPS 설계)

  • Sin, Min-Jeong;Kim, Chun-Sung;Hwang, Jung-Goo;Park, Sung-Jun
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.528-529
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    • 2015
  • 본 논문은 DC-DC 플라이백 컨버터 회로를 바탕으로, 고전압 입력으로부터 다채널의 절연된 저전압을 출력하는 고압 SMPS에 관한 것이다. 제안된 토폴로지는 고전압을 분배하는 커패시터와 MCU 전용의 커패시터를 직렬로 구성하고, 각 커패시터에 분배된 전압을 입력으로 다중여자 방식의 플라이백 컨버터 구조로 되어있다. 직렬 커패시터 구조는 고압환경에서의 소자들의 절연 및 전압스트레스를 저감할 수 있으며, MCU 전용의 커패시터는 시스템의 초기구동을 위한 자가충전(Self-Power) 및 Black-Start의 시스템 안정화 구조이다. 또한 다중여자방식은 변압기의 단일 코어를 사용하여 스위칭 전류를 흘려줌으로서 커패시터의 전압불균형을 막을 수 있는 장점을 가지고 있다. 제안된 토폴로지는 시뮬레이션을 통하여 타당성을 검증하였다.

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Fabrication and Driving of Charged particle type display (대전입자형 디스플레이의 제조 및 구동)

  • Lee, Dong-Jin;Kim, Sung-Woon;Hwang, In-Sung;Kim, Chul-Ju;Kim, Young-Cho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.72-73
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    • 2007
  • The charged particle have characteristics of high-contrast ratio and wide-view angle, quick-response time. When positive voltage is applied to the upper electrode, the yellow particles with negative charge move toward the upper substrate and the black particles with positive charge move toward opposite direction. We have developed the putting method that can fill particles in cell of panel and control the amount of charged particles. We investigated putting method, fabrication process, aging and driving for charged particle type display.

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SMPS Design for high voltage input (고출력 SMPS 설계)

  • Song, Gwang-Cheol;Park, Sung-Min;Song, Kwang-Seok
    • Proceedings of the KIPE Conference
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    • 2015.11a
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    • pp.169-170
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    • 2015
  • 본 논문은 Forward Converter방식의 DC/DC 컨버터 회로를 기반으로, 1000[V]급에 해당하는 고전압 입력으로부터 절연된 저전압을 출력하는 고압SMPS에 관한 것이다. 제안된 토폴로지는 고전압을 분배하는 커패시터와 MCU 전용의 커패시터를 직렬로 구성하고, 각 커패시터에 분배된 전압을 입력으로 다중여자 방식의 컨버터 구조로 되어있다. 직렬 커패시터 구조는 고압환경에서 각 소자들의 절연 및 전압스트레스를 저감할 수 있으며, 제어기 전용의 커패시터는 시스템의 초기구동을 위한 자가충전 (Self-Power) 및 Black-Start의 시스템 안정화 구조이다. 또한 각 모듈에 연결된 모든 DC/DC컨버터 출력이 하나의 변압기에 연결되는 구조를 취하고 있어 Passive방식의 단일 코어를 갖는고주파 변압기를 통하여 자속을 공유함으로 밸런싱이 가능하다. 따라서 본 논문에서 제안된 공진회로는 PISM을 이용한 시뮬레이션과 실험을 통해 제안된 알고리즘의 타당성과 우수성을 검증하였다.

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The Multi-objective Optimal Design of Thermopile Sensor Having Beam or Membrane Structure (빔 혹은 멤버레인 구조를 가지는 써모파일 센서의 다목적 최적설계)

  • Lee, Jun-Bae;Kim, Tae-Yoon
    • Journal of Sensor Science and Technology
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    • v.6 no.1
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    • pp.6-15
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    • 1997
  • This paper presents the multi-objective optimal design of thermopile sensor having beam or membrane structure. The thermopile sensor is composed of $Si_{3}N_{4}/SiO_{2}$ dielectric membrane, Al-polysilicon thermocouples and $RuO_{2}$ thin film for black body. The sensing method is based on the Seebeck effect which is originated from the temperature difference of the two positions, black body and silicon rim. The objective functions of the presented design are sensitivity, detectivity and thermal time constant. The modelling of the sensor is proposed including the package. The multi-objective optimization technique is applied to the design of the sensor not only inspecting the modelling equation but also simulating mathematical programming method. Especially, fuzzy optimization technique is adapted to get the optimal solution which enables the designer to reach the more practical solution. The design constraint of the voltage output originated from the change of the environmental temperature is included for practical use.

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Study on the new development of combined electrochemical processes using pulse current (마이크로 펄스 전해 복합가공에 관한 연구)

  • 박정우;이은상;문영훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.918-921
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    • 2002
  • Some investigators who have tried to achieve the highly smooth surface finish using electrochemical processes have reported that high current density produced lustrous surfaces while the opposite conditions produced a passive layer and had a tendency to produce a black surface. However, processing at a low current density may produce a non-lustrous surface but the improvement of dimensional accuracy of the surface is significant. The surface with pulse process was a bit more lustrous than with continuous current but the black passive layer still could be found at grooved surface. There are two ways to achieve highly smooth surface finish. One is brushing it with a brush the other is electrochemical machining (ECM) with high current. The former method is the most common polishing practice, but not only may the surface obtained differ from operator to operator, but precision smooth surface on micro grooves are difficult to obtain. The latter one recently has been used to produce a highly smooth surface after EDM process. However, the material removal rate in ECM with high current is relatively high. Hence the original shape of the micro grooves, which was formed by electrochemical micro-machining (EMM) process, may be destroyed. In this study, an electrochemical polishing process using pulse current is adopted as a possible alternative process when micro grooves formed by EMM process should be polished. Mirror-like micro grooves with lustrous and smooth surface can be produced electrochemically with pulse current because the voltage and current used can be lower than the case of continuous current. This study will discuss the accurate control of physical and electrical conditions so as to achieve mirror-like micro grooves with lustrous and smooth surface without destroying the original shape of micro grooves.

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Operating Characteristic Analysis of Optic Temperature Sensor for Overheat Detection in Panel Board (분전함에서 이상발열 감지를 위한 광온도센서의 동작특성 분석)

  • Moon, Hyun-Wook;Kim, Dong-Woo;Gil, Hyung-Jun;Kim, Dong-Ook;Lee, Ki-Yeon;Kim, Hyang-Kon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.10
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    • pp.100-106
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    • 2009
  • In this study, methods of overheat detection at the coupling or wire in electrical facility are investigated, operating characteristic about the optic temperature sensor for continuous on-line temperature monitoring in diagnostics system of electrical facility is analyzed. Heating sources in the experiment for operating characteristics of optic temperature sensor use black body and hot plate, output voltage of optic temperature sensor in accordance with temperature variation is analyzed. Overheat generation due to poor contact at the circuit breaker in panel board detects using a thermocouple, infrared thermal camera and optic temperature sensor, and experiment results are analyzed. The effect of optic temperature sensor is the same that of other methods. These results expect to use basic research material for adjusting field of electrical diagnostics system using RFID type optic temperature sensor in the near future.

AMOLED Pixel Circuit with Electronic Compensation for Vth and Mobility Variation in LTPS TFTs (LTPS TFT의 Vth와 mobility 편차를 보상하기 위한 AMOLED 화소 회로)

  • Woo, Doo-Hyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.4
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    • pp.45-52
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    • 2009
  • We proposed a new pixel circuit and driving method for the large-area, high-luminance AMOLED applications in this study. We designed with the low-temperature poly-silicon(LTPS) thin film transistors(TFTs) that has poor uniformity but stable characteristic. To improve the uniformity of an image, the threshold voltage($V_{TH}$) and the mobility of the TFTs can be compensated together. The proposed method overcomes the previous methods for mobility compensation, and that is profitable for large-area applications. Black data insertion was introduced to improve the characteristics for moving images. AMOLED panel can operate in two compensation mode, so the luminance degradation by mobility compensation can be released. The scan driver for controlling the pixel circuits were optimized, and the compensation mode can be controlled simply by that. Final driving signal has large timing margin, and the panel operates stably. The pixel circuit was designed for 14.1" WXGA top-emission ANGLED panel. The non-uniformity of the designed panel was estimated under 5% for the mobility compensation time of 1us.

Study on the Magnetic Shield Effect of Carbon-based Materials at Extremely Low Frequency (탄소계 소재를 이용한 극저주파 영역에서의 자기 차폐효과 연구)

  • Oh, Seong Moon;Kang, Dong Su;Lee, Sang Min;Baek, Un Gyeong;Roh, Jae Seung
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.15-20
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    • 2015
  • To examine the magnetic shielding effect for carbon-based materials at extremely low frequencies (60 Hz), two types of carbon black (Super-P and Denka Black) and a natural graphite (HC-198) were mixed into organic binder at 10 wt.% to produce a coating solution, and a powder coating with varying thickness was applied on an aluminum disk measuring 88 mm in radius. A device was developed to measure the sheielding effect at extremely low frequencies. A closed circuit was achieved by connecting a transformer and a resistor. The applied voltage was fixed at 65 V, and the magnetic field was measured to being the range of 4.95~5.10 mG. Depending on the thickness of the coating layer, the magnetic field showed a decreasing trend. The maximum decrease in the magnetic field of 38.3% was measured when natural graphite was coated with specimens averaging $455{\mu}m$. This study confirmed that carbon-based materials enable magnetic shielding at extremely low frequencies, and that the magnetic shielding effect can be enhanced by varying the coating thickness.

Research on the Manufacturing Technology for a PDMS Structure-Based Transpiration Generator Using Biomimetic Capillary Phenomenon (생체모방 모세관 현상을 이용한 PDMS 구조체 기반 증산발전기 제조기술 연구)

  • Seung-Hwan Lee;Jeungjai Yun;So Hyun Baek;Yongbum Kwon;Yoseb Song;Bum Sung Kim;Yong-Ho Choa;Da-Woon Jeong
    • Journal of Powder Materials
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    • v.30 no.3
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    • pp.268-275
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    • 2023
  • The demand for energy is steadily rising because of rapid population growth and improvements in living standards. Consequently, extensive research is being conducted worldwide to enhance the energy supply. Transpiration power generation technology utilizes the vast availability of water, which encompasses more than 70% of the Earth's surface, offering the unique advantage of minimal temporal and spatial constraints over other forms of power generation. Various principles are involved in water-based energy harvesting. In this study, we focused on explaining the generation of energy through the streaming potential within the generator component. The generator was fabricated using sugar cubes, PDMS, carbon black, CTAB, and DI water. In addition, a straightforward and rapid manufacturing method for the generator was proposed. The PDMS generator developed in this study exhibits high performance with a voltage of 29.6 mV and a current of 8.29 µA and can generate power for over 40h. This study contributes to the future development of generators that can achieve high performance and long-term power generation.