• 제목/요약/키워드: Power quality

검색결과 959건 처리시간 0.453초

교류 전기철도 급전시스템을 위한 철도용 전기품질 보상장치의 제어방법 (Control of Railway Power Quality Conditioner for AC Electrified Railway Systems)

  • 박한얼;송중호
    • 조명전기설비학회논문지
    • /
    • 제24권8호
    • /
    • pp.48-54
    • /
    • 2010
  • 교류 전기철도 시스템은 비선형 단상 부하인 차량의 부하특성으로 인해 고조파 왜곡, 무효전력 발생, 3상 불평형과 같은 전기품질 문제를 가지고 있다. 이 같은 전기품질 문제는 철도 시스템뿐만 아니라 철도와 연계된 다른 건전한 계통에도 악영향을 미치게 된다. 따라서 본 논문에서는 이와 같은 전기철도 급전시스템의 전기품질 문제를 보상하기 위해 철도용 전기품질 보상장치(RPQC; railway power quality conditioner)를 적용하고, SRF(synchronous-reference-frame) 제어를 이용한 RPQC의 제어방법을 제안한다. 제안하는 제어방법을 통해 RPQC는 고조파 왜곡, 무효전력, 부하 불평형과 같은 전기품질 문제를 순시적으로 보상할 수 있으며, 시뮬레이션을 통해 이를 검증한다. 시뮬레이션 결과는 제안한 RPQC 제어방법의 타당성을 보여주고 있다.

전력계통 전력품질 통합진단시스템 개발 (The Development of Integrated Power Quality Diagnosis System for Power System)

  • 곽노홍;전영수;박상호;이일무;박희철
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
    • /
    • pp.277-279
    • /
    • 2005
  • Recently, due to the increase of power conversion devices and nonlinear loads with the development of information, communication and control technologies, the instantaneous minute interruption factors such as voltage & current harmonics, surge occurring frequency, instantaneous voltage variation, voltage unbalance, flicker etc. have greatly threatened the power quality, and the deterioration of electric power facilities and the functional error of controllers are increasing. As such an instantaneous minute interruption appears to be small and local, accurate evaluation with measurement is difficult and total analysis system is required through a wide range of power quality effect analysis such as the simultaneous measurement on various power supply phenomena and the analysis on the interrelation with system loads. Most of conventional power quality diagnosis equipments have beer developed and applied, which were able to measure the stability rate of frequency, the stability rate of voltage, the electricity-failure duration etc, However, they were insufficient to analyze the system present situation, understand the cause of the failure occurred by the problem of power quality and analyze out the phenomena. Accordingly, this study will address the development of the system for a wide range of power quality diagnosis over the present level, the system for supporting the determination such as the analysis on risk factors, failure mode and impact, the system for harmonic evaluation based on international standards(IEC 61000 Series) and the total power quality diagnosis network & system with the extension and openness as a local and national-scale broadband power quality diagnosis system.

  • PDF

새로운 전기품질 감시장치 개발 및 전기품질 관리방안 (Development of New Monitoring System for Power Quality Management)

  • 남기영;최상봉;류희석;이재덕;정성환;김대경
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
    • /
    • pp.447-449
    • /
    • 2005
  • Power supply system & environment have been changed according to the universal global electrification, the pursuit of improving productivity and the convenience of life. The various kinds of modem electric facilities and almost of all kinds of digital devices embedded microprocessor are very sensitive to the supplied power quality variations. So, they are stopped and result in large economic damage when even the deterioration of power quality with short duration is occurred, which was not so fatal to the conventional industrial facilities and devices. Conversely, those facilities and digital devices generate many kinds of power quality problems such as harmonic.;, flicker, voltage drop, etc. This paper presents the status of power quality and outlines the development of a new power quality monitoring system based on the experience of a series of authors' researches and field measurements for industrial customers in Korea. It also proposes the functions of the monitoring device and the efficient analysis method based on the Korean electrical act and international standards on power quality. Finally, the authors suggest some countermeasures for advancing the power quality to cope with the competitive electric power market and customers' needs after domestic restructuring of electric power industry.

  • PDF

Power Flow Control of a Multi-bus/Three-feeder Distribution System Using Generalized Unified Power Quality Conditioner

  • Mohammed, B.S.;Ibrahim, R.;Perumal, N.;Rao, K.S. Rama
    • Journal of Electrical Engineering and Technology
    • /
    • 제10권1호
    • /
    • pp.8-17
    • /
    • 2015
  • This paper analyses the power flow of a three-feeder/multi-bus distribution system by a custom Generalized Power Quality Conditioner (GUPQC). The GUPQC has been realized by three voltage source converters (VSCs) coupled back-to-back through a common DC-link capacitor on the DC-side. One feeder was controlled by the shunt compensator, whereas each of the other two feeders was controlled by the proposed novel series compensator. The GUPQC has the capability to simultaneously compensate voltage and current quality problems of a multi-bus/three-feeder distribution system. Besides that, the power can be transferred from one feeder to other feeders to compensate for poor power quality problems. Extensive simulation studies were carried out by using MATLAB/SIMULINK software to establish the ability of the GUPQC to improve power quality of the distribution systems under distorted supply voltage conditions.

순간정전에 대한 보상능력을 갖는 UPQC(Unified Power Quality Conditioner)의 성능해석 (Performance Analysis of UPQC(Unified Power Quality Conditioner) with Compensation Capability for Voltage Interruption)

  • 김희중;배병열;한병문;설승기;조보형
    • 대한전기학회논문지:전력기술부문A
    • /
    • 제52권5호
    • /
    • pp.279-286
    • /
    • 2003
  • A new UPQC(unified power quality conditioner), which consists of series inverter, shunt inverter, dc/dc converter, and energy storage, is proposed. The proposing UPQC can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance, and voltage interruption. The control strategy for the proposing UPWQC was derived using the instantaneous power method. The performance of proposing system was analyzed by means of the EMTDC/PSCAD simulation and the experimental work with the hardware prototype. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems or industrial power systems and can be utilized for the custom power device in the future distribution system.

DSP를 기반으로 운용되는 전력품질 감시 시스템 (A Power Quality Monitoring System Based On The Digital Signal Processor)

  • 이교성;이용제;임상욱;조풍구;김양모
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
    • /
    • pp.173-175
    • /
    • 2003
  • To improve the power quality, various types of equipment are used. However, without determining the existing levels of power quality, electric utilities and customers cannot adopt suitable strategies and equipment to improve the power quality. Therefore, in this paper, power quality monitoring system is discussed.

  • PDF

HVDC Overhaul 기간 중 제주계통에 연계된 풍력발전의 전력품질 분석 (Power Quality Analysis of Wind Farms interconnected in Jeju System during HVDC Overhaul)

  • 채우규;윤기갑;조성수;정원욱
    • 전기학회논문지
    • /
    • 제57권11호
    • /
    • pp.1946-1953
    • /
    • 2008
  • Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.

U57 풍력발전기 전력품질 실증연구 (Study of Power Quality Measurement U57 Windturbine)

  • 이병철;박희철;황진수;류지윤
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2008년도 추계학술대회 논문집
    • /
    • pp.310-314
    • /
    • 2008
  • The exploitation of the wind energy resource is a rapidly growing area world-wide. The number of installed units is continuously increasing, and it is important to respect and to deal with the impact of wind turbine. This paper addresses the power quality characteristics of U57 Wind Turbine. 750kW gearless type wind turbine for low wind speed, named U57, is developed by UNISON. The power quality measurement system consists of measuring WTG output current, line-to line voltage and wind speed signal. With using measured data, power quality measurement is evaluated about maximum power, reactive power, voltage fluctuation, harmonics according to IEC 61400-21.

  • PDF

A Single-Phase Unified Power Quality Conditioner with a Frequency-Adaptive Repetitive Controller

  • Phan, Dang-Minh;Lee, Hong-Hee
    • Journal of Electrical Engineering and Technology
    • /
    • 제13권2호
    • /
    • pp.790-799
    • /
    • 2018
  • This paper proposes a single-phase unified power quality conditioner (S-UPQC) for maintaining power quality issues in a microgrid. The S-UPQC can compensate the voltage and current harmonics, voltage sag, and swell as a dynamic voltage restorer (DVR), regardless of variations in the grid frequency. Odd harmonics are treated as even-order harmonics in a rotating frame to implement the harmonic compensators with only one repetitive controller (RC) without any harmonic extractor. The dynamic performance is improved and the delay time is reduced in the RC. The S-UPQC control scheme is designed to maintain accurate and stable operation under deviations of the grid frequency by using the Lagrange interpolation-based finite-impulse-response (LIFIR) filter approximation method. The proposed control schemes were validated through a simulation and experiment.

Definition of Powers and Power Quality Factors at a Point of Common Coupling in Single-Phase Systems and Three-Phase Systems

  • Kim, Hyosung;Frede Blaabjerg;Jensen, Birgitte-Bak
    • Journal of Power Electronics
    • /
    • 제2권1호
    • /
    • pp.32-45
    • /
    • 2002
  • This paper proposes an unified definition of powers for various circuit conditions such as balanced/unbalanced, sinusoidal/non-sinusoidal, and linear/nonlinear, fur single-phase systems and three-phase systems. Conventional reactive power is more classified into an interactive power and an alternating power. These powers are defined both in the time domain and the frequency domain consistently, and agree well with the conservation law. Several important power quality factors are defined to measure and evaluate the power quality fur the various circuits in the single-phase and three-phase systems. Simulation results show the power quality factors can evaluate and classify the various circuit conditions clearly.