• Title/Summary/Keyword: AC Electric field

Search Result 268, Processing Time 0.027 seconds

고압중전기기용 절연신소재 EMNC와 EMNSC의 특성연구 (Properties of EMNC and EMNSC for Insulation New Material as Apply to High Voltage Heavy Electric Machine)

  • 박재준
    • 전기학회논문지
    • /
    • 제61권10호
    • /
    • pp.1454-1460
    • /
    • 2012
  • In order to develop an new electric insulation material for heavy electric equipments, epoxy/micro/nano composite (EMNC) was prepared by mixing micro-silica with nano layered silicate, where the nano layered silicate was synthesized by our electric field dispersion method, EMNSC was prepared by treating the EMNC with a silane coupling agent. Thermal properties such as glass transition temperature (Tg) and thermal expansion coefficient, and DMA characteristics were studied, and mechanicla properties such as tensile and flexural tests were performed. AC electrical insulation strength was also tested. All properties of EMNSC were modified by treating EMNC with silane coupling agent and it was confirmed that our new developed composites could be used in the heavy electric equipments.

Space Charge Measurement as a Diagnostic Tool to Monitor Ageing in Polymeric Materials

  • Chen, George
    • Transactions on Electrical and Electronic Materials
    • /
    • 제7권5호
    • /
    • pp.235-239
    • /
    • 2006
  • Charge dynamics in polymeric materials after aged under ac electric field using the pulsed electroacoustic (PEA) technique is reported. The emphasis is placed on charge decay. The charge dynamics of the ac aged additive free low density polyethylene (LDPE) samples under dc bias differ from the sample without ac ageing, indicating changes brought in by ac ageing. It is believed that a slow decay rate of charge in the ac aged sample is related to the formation of deep traps in the material. However, chemical analysis by infrared spectroscope (FTIR) and Raman microscope reveals no significant chemical changes taken place in the bulk of the material after ac ageing. Further experiments on irradiated LDPE have revealed a similar behaviour, i.e. the charge decay is slower in irradiated samples than that of fresh sample. The findings presented clearly indicate that space charge measurement can be used as a diagnostic tool to monitor ageing in polymeric materials.

대용량 전력 전송을 위한 초전도 전력케이블의 교류손실 특성 분석 (AC Loss Characteristic Analysis of Superconducting Power Cable for High Capacity Power Transmission)

  • 이석주
    • 한국산업정보학회논문지
    • /
    • 제24권2호
    • /
    • pp.57-63
    • /
    • 2019
  • 점차적으로 늘어나는 전력 수요의 공급을 원활히 하기 위해서 발전 설비 뿐만 아니라 전력을 전송하기 위한 전력케이블의 증설도 반드시 필요하다. 하지만 대부분의 도심지에 전력을 공급하기 위한 전력케이블의 증설은 추가적인 케이블의 설치공사를 위한 공간을 필요로 하고 현재 국내 도심지에 케이블 설치를 위한 공간이 부족한 실정이다. 이에 동일한 사이즈로 더 많은 전력을 전송할 수 있는 초전도 전력 케이블은 부족한 케이블의 설치공간을 극복할 수 있는 대안으로 등장하였다. 하지만 대용량의 전력 전송의 이점을 가지고 있는 초전도 전력케이블은 교류 시스템에서의 일부 손실을 가지고 있다. 따라서 교류 전력 전송 시스템에서 초전도 전력 케이블을 도입하기 위해서는 교류손실의 설계 및 분석이 반드시 필요하다. 이에 본 논문에서는 다양한 초전도 전력케이블의 교류 손실 분석을 통하여 실제 초전도 전력 케이블의 제조 및 실계통 적용에 고려하고자 한다. 단일 초전도 선재에 대한 교류 손실의 이론적인 계산 방법은 존재하지만 많은 수로 구성된 초전도 전력 케이블의 교류손실 계산은 쉽지가 않다. 저자는 초전도의 E-J (Electric field-current density) 특성이 고려된 전자기적 유한요소해석법을 이용하여 다양한 종류의 초전도 전력케이블 교류 손실을 분석하고자 한다. 또한 본 초전도 전력케이블의 교류손실 특성 분석은 실계통에 적용될 초전도 전력케이블의 설계 및 개발에 중요한 요소로 작용될 것이다. [1-4].

국내 전철 및 가전제품을 대상으로 한 전자장 수준 실태조사 (A survey on the EMF Levels of Study and Electric Appliances in Korea)

  • 장성기;조용성;이석조;유승화;정경미;임준호
    • 한국산업보건학회지
    • /
    • 제15권1호
    • /
    • pp.71-81
    • /
    • 2005
  • The purposes of this study was to collect, analyze, and describe the MF exposure levels from subways in Korea and to measure and evaluate the MF levels generated from electric appliances used at general homes. The target subway lines were Seoul Metropolitan Line 1 to Line 8, Bundang Line, Incheon Line, Daegu Line, Gwangju Line, and Busan Line 1 and Line 2. We measured at each station in those subway lines and, all the train types (pantograph-equipped, motor-equipped, and common), and platform types(facing and isolating) were investigated by the distance(80, 200, 400 cm) from the train on 19 targeted subway lines using 3 magnetic field measuring devices (EMDEXII, Enertech Co.) during the survey from January till October, 2004. On the other hand, the levels of the 60Hz magnetic fields generated from 14 items of home electric appliances such as electric blankets, hair dryers, electric razors, etc. were measured at 10 general homes using 5 EMDEXII meters with a sampling interval of 1.5 second by the distance(surface, 30, 50, 100, 300cm ) from the target electric appliances. The survey results in the whole subway lines examined in this study were as follows; Seoul Metropolitan Line 4 using AC(alternating current) power source showed the highest mean value of $2.85{\mu}T$, followed by Seoul Metropolitan Line 1 running between Seoul and Incheon using AC($2.78{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Uijongbu using AC($2.73{\mu}T$), Bundang Line using AC($1.79{\mu}T$), Seoul Metropolitan Line 1 connected from Yongsan using AC($1.67{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Suwon using AC($0.79{\mu}T$), and so on. In general, the intensity of the magnetic field in the subway systems in Korea was significantly higher when using AC($2.14{\pm}0.91{\mu}T$) than when using DC($0.29{\pm}0.44{\mu}T$) power source. Among the home electric appliances examined, microwave ovens showed the highest mean value of $7.69{\mu}T$, followed by hair dryers($6.47{\mu}T$), vacuum cleaners($5.27{\mu}T$), televisions ($2.26{\mu}T$), electric blankets($1.38{\mu}T$), personal computers ($0.81{\mu}T$), and so on. Two items of electric appliances showed the excess value of $0.2{\mu}T$ at the distance of 30cm in the MF exposure level; electric razors $1.58{\pm}2.13{\mu}T$ and vacuum cleaners $0.48{\pm}0.44{\mu}T$. As a whole, this study showed a tendency that the shift of the MF levels according to the increase of distance from the electric appliances was lower than those of the results surveyed in UK and USA. As a result, this study is expected to suggest meaningful data for the future study in exposure assessment of magnetic fields and for the establishment of guidelines for subways and electric appliances in Korea. More detailed and large scaled exposure assessment studies should be performed continuously to get the various and useful information on health risk assessment of MFs in Korea.

고효율 전기기기 특허동향 분석 (Patent map development of High-efficiency electric machineries)

  • 박종진;이창호;김남정
    • 한국기술혁신학회:학술대회논문집
    • /
    • 한국기술혁신학회 2000년도 추계 학술대회(The 2000 Autumn Conference of korea Technology Inovation Society)(한국기술혁신학회)
    • /
    • pp.177-193
    • /
    • 2000
  • In foreign countries, high-efficiency electric machineries have been developed in view of cost reduction, environmental issues, energy conservation etc. Especially they focus on developing energy conservation measures and demand-side management. Thus, patent application and secure of patent claims are on the rise as important issues in this field. In this paper, we analyzed patent application trends about inverters, ac/dc converters, reactive power control equipments, high-efficiency transformers and electric ballasts among high-efficiency electric machineries. First, we analyzed general technology trends, and constructed patent technology data. Second, we graphed patent application trends in terms of application years, assignees and nations.

  • PDF

전동차용 고성능 AC구동시스템의 개발 (A High Performance AC Propulsion System for Electric Car)

  • 정기찬;방이석;김두식;서광덕;김남해
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1996년도 하계학술대회 논문집 A
    • /
    • pp.278-280
    • /
    • 1996
  • This paper presents a high performance AC propulsion system for electric car to improve traction capability. The presented VVVF inverter was composed of as GTO thyristor and the the controller was fully digitalized by using 32bit DSP. The improved PWM algorithms and the new adhesion control were adapted to improve traction characteristics. This system could be possible the higher reliability and flexibility. The field test results showed the higher performances characteristics of the presented system.

  • PDF

불평등전계에서의 건조공기/에폭시 복합절연물의 에폭시 두께에 따른 AC 파괴전압 분석 (Analysis of AC Breakdown Voltage accoding to epoxy thickness of Composite Insulation for Dry-Air/Epoxy under non-uniform electric field)

  • 허준;이승수;임기조;정해은;강성화
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
    • /
    • pp.113-114
    • /
    • 2008
  • The purpose of this paper is to analyze AC Breakdown of solid/air composite insulation depending on the thickness and the pressure of dry air for eco-friendly insulation. SF6 gas has been widely used in electric equipment as gas insulation because of high dielectric strength and arc extinguishing performance. However, because SF6 gas is one of the green house effect gases, alternative insulation such as SF6 mixture, extremely low temperature gas, vacuum, liquid and solid insulating are being investigated.

  • PDF

액체 질소중 교류방전 진전에 따른 방사전자파의 주파수 스펙트럼 특성 (The Characteristics of Frequency Spectrum of Radiated Electromagnetic Waves with AC Discharge Progress in Liquid Nitrogen)

  • 박광서;윤대희;이상훈;이현동;김충년;최병주;김기채;이광식
    • 대한전기학회논문지:전기물성ㆍ응용부문C
    • /
    • 제52권3호
    • /
    • pp.123-129
    • /
    • 2003
  • In this paper, a relationship between AC discharge progress and the radiated electromagnetic waves was investigated by measuring electromagnetic waves using a biconical antenna and a spectrum analyzer. The frequency spectrum of the radiated electromagnetic waves were measured at the atmospheric pressure in liquid nitrogen($LN_2$) during partial discharges progressed by AC high voltage in nonuniform electric field. Front the results of this study, a new method was introduced for measurement and analysis of the radiated electromagnetic waves with discharge progress in $LN_2$ Besides. according to the consideration of the mutual relation between frequency spectrum of the radiated electromagnetic waves and discharge progress, it was confirmed that detecting partial discharge and estimating discharge progress could be possible. It is considered that these results obtained from this investigation may be used as fundamental data for diagnosis and prediction of electric insulations about superconducting and cryogenic power equipments.

복합절연물내 기체의 압력 및 고체의 두께변화가 AC 절연파괴에 미치는 영향 분석 (AC Breakdown Analysis of Composite-Insulation by the Thickness of epoxy and the Variation of Pressure)

  • 정해은;김병철;윤재훈;강성화;임기조
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
    • /
    • pp.194-195
    • /
    • 2007
  • $SF_6$ gas used widely as insulating component in electric power industry has excellent in insulation and arc extinguishing performance in gas-insulated switchgear. However, the concern about eco-friendly alternative gas is currently rising because $SF_6$ gas is one of the main greenhouse gases. In this paper, dry-air and composite-insulation (dry-air+epoxy) as the alternative technology for $SF_6$ gas insulation is studied. Under the gas pressure ranged from 0.1 to 0.6MPa, the breakdown voltage of dry-air were measured in AC electric field. The data of composite-insulation were acquired by changing the thickness of epoxy used in each composite-insulation under the same condition.

  • PDF

고온 초전도 케이블 시스템 설치 밀 운전을 위한 연구 (Research for Installation and Operation of High Temperature Superconducting Cable System)

  • 최형식;손송호;황시돌
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
    • /
    • pp.653-657
    • /
    • 2005
  • The commercial contract was made firstly in the world for one set of high temperature superconducting(HTS) cable system between buyer, Korea Electric Power Research Institute and seller, Sumitomo Electric Industries, Ltd. in August 2004. After fabrication, test and examination, the HTS cable system will be installed at the KEPRI's test field in Gochang, Jeonbuk province from the time of July 2005. KEPRI is preparing measurement and test facilities for field test of the HTS cable system and carrying out researches into the design and construction of superconducting cable test building, evaluation of cooling performance, measurement of AC loss, analysis of the quench phenomena due to excess current and means of linking the HTS cable system to the existing electric power supplying system. The constitution of, the method to install and the plan of test operation of the HTS cable system will be presented in this paper.

  • PDF