• Title, Summary, Keyword: Voltage sag

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2MVA SSFG(Sag Swell Flicker Generator) Development for Actual Test of Custom Power Device (전력품질 향상기기의 실증시험을 위한 2MVA SSFG(Sag Swell Flicker Generator) 개발)

  • Kim H.J.;Chung Y.H.;Kwon G.H.;Park T.B.;Moon J.I.;Jeon Y.S.
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.6
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    • pp.626-633
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    • 2005
  • This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

An Investigation into the Impact on Voltage Sag due to Faults in Low Voltage Power Distribution Systems

  • Aggarwal R. K.
    • KIEE International Transactions on Power Engineering
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    • v.5A no.2
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    • pp.97-102
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    • 2005
  • Voltage sags are the most widespread quality issues affecting distribution systems. This paper describes in some detail the voltage sag characteristics due to different types and locations of fault in a practical low voltage power distribution system encountered in the UK. The results not only give utility engineers very useful information when identifying parts of the system most likely to pose problems for customer equipments, but also assist the facility personnel to make decisions on purchasing power quality mitigation equipment.

Calculation of the Area of Severity for Voltage Sag Assessment (순간전압강하 평가를 위한 가혹지역의 계산)

  • Park, Chang-Hyun;Hong, Jun-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.6
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    • pp.1034-1040
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    • 2010
  • This paper presents a calculation method of the area of severity for the stochastic assessment of voltage sags. In general, the annual expected numbers of voltage sags at an individual load point can be estimated stochastically. However, in order to assess the system voltage sag performance considering many sensitive load points together, it is necessary to determine and analysis the area of severity for the load points. The area of severity to voltage sags is the network region where the fault occurrences will simultaneously lead to voltage sags at different load points. In this paper, the concept of the voltage sag assessment and the calculation method of the area of severity are addressed. The analysis of the area of severity is performed on the IEEE 30-bus test system by using the proposed method. The method is useful for the stochastic assesment of voltage sags and the establishment of systematic plans for voltage sag mitigation.

Bus-voltage Sag Suppressing and Fault Current Limiting Characteristics of the SFCL Due to its Application Location in a Power Distribution System

  • Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1305-1309
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    • 2013
  • The application of the superconducting fault current limiter (SFCL) in a power distribution system is expected to contribute the voltage-sag suppression of the bus line as well as the fault-current reduction of the fault line. However, the application effects of the SFCL on the voltage sag of the bus line including the fault current are dependent on its application location in a power distribution system. In this paper, we investigated the fault current limiting and the voltage sag suppressing characteristics of the SFCL due to its application location such as the outgoing point of the feeder, the bus line, the neutral line and the 2nd side of the main transformer in a power distribution system, and analyzed the trace variations of the bus-voltage and fault-feeder current. The simulated power distribution system, which was composed of the universal power source, two transformers with the parallel connection and the impedance load banks connected with the 2nd side of the transformer through the power transmission lines, was constructed and the short-circuit tests for the constructed system were carried out. Through the analysis on the short-circuit tests for the simulated power distribution system with the SFCLs applied into its representative locations, the effects from the SFCL's application on the power distribution system were discussed from the viewpoints of both the suppression of the bus-voltage sag and the reduction of the fault current.

Development of a Voltage Sag Assessment Program Considering Generator Scheduling and Voltage Tolerance (발전기 스케줄링과 부하 전압민감도를 고려한 순간전압강하 평가 프로그램 개발)

  • Park, Chang-Hyun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.4
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    • pp.92-100
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    • 2009
  • This paper presents a voltage sag assessment program. The program provides various functions for stochastic assessment of voltage sags such as short-circuit analysis, the determination of the area of vulnerability and the calculation of expected sag frequency(ESF). Effective data visualization functions based on computer graphics and animation were also implemented in the developed program. In this paper, the concept of voltage sag assessment and the assessment method considering generator scheduling and time-varying fault rates are presented. The influence of generator scheduling and time-varying fault rates on voltage sag prediction is also described by performing case studies using the developed program.

The study on the characteristics of operating limit of low voltage electric machine under the effects of voltage quality (순간전압품질이 저압 전기기기 운전한계에 미치는 특성연구)

  • Park, In-Deok;Jeong, Sung-Won;Gim, Jae-Hyeon;Lee, Geun-Joon
    • Proceedings of the KIPE Conference
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    • pp.95-97
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    • 2007
  • This paper studies on operating limit curve of low voltage electric machinery with respect to source voltage variation or sag. Also, it discusses electric machine and compensation equipment design methodology based on voltage quality effect assessment technology. Voltage quality standards, such as SEMI47, CBEMA, ITIC curve are regarded to examine the relation between time constants of load and sagging time of sag generator, the load(low voltage electric machinery) study. Voltage sag characteristics of loads, time constant and sag relation voltage-time operating limits are tested and verified.

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The study on the characteristics of operating limit of low voltage electric machine under the effects of voltage quality (전압품질이 저압 전기기기 운전에 미치는 특성연구)

  • Park, In-Deok;Lee, Geun-Joon
    • Proceedings of the KIEE Conference
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    • pp.33-35
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    • 2007
  • This paper studies on operating limit curve of low voltage electric machinery with respect to source voltage variation or sag. Also, it discusses electric machine and compensation equipment design methodology based on voltage quality effect assessment technology. Voltage quality standards, such as SEMI47, CBEMA, ITIC curve are regarded to examine the relation between time constants of load and sagging time of sag generator, the load(low voltage electric machinery) study. Voltage sag characteristics of loads, time constant and sag relation voltage-time operating limits are tested and verified.

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Instantaneous Voltage Sag Corrector in Distribution Line Using Series Compensator (배전계통에서의 직렬보상을 이용한 순시전압강하 보상기)

  • Lee, Sang-Hoon;Choi, Jae-Ho
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.1
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    • pp.15-22
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    • 2001
  • In this paper, a VSC(Voltage Sag Corrector) is discussed for the purpose of power quality enhancement. A fast detecting technique of voltage sag is accomplished through the detection of instantaneous value on synchronous reference frame. A robust characteristic against the noise is available by inserting the first order low pass filter in the detection circuit. The formula and the filter design process is described properly with the mathematical equations. Because the VSC system supply the active power to load, it is required to design the proper size of the energy storage system, In this paper, the capacitor bank is used as an energy storage system, and the size of the capacitor is designed from the point of view of input/output energy as the output power rating and the amplitude and duration time of the voltage sag. The simulation is accomplished by PSCAD/EMTDC.

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Assessing the Effect of Voltage Sag in Distribution System Using a Fuzzy Risk Assessment Model (퍼지 위험도 평가 모델을 이용한 배전계통의 순간전압강하 영향 평가)

  • Yun, Sang-Yun;Oh, Jung-Hwan;Han, Byung-Duk;Kim, Jae-Chul;Park, Joong-Shin;Lim, Dong-Gyun
    • Proceedings of the KIEE Conference
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    • pp.1085-1087
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    • 1999
  • In this paper, we propose the method for assessing the effect of voltage sag in power distribution system using fuzzy risk assessment model. The proposed method is based on SCBEMA curve that expresses the representative susceptibility curve by voltage sag for each customer type. These corves are made using the CBEMA curves obtained from the experiment for the customers'sensitive equipment. In order to transform SCBEMA curves to the probability damage by voltage sag, the fuzzy risk assessment model is used in this paper. Case studies were performed to analyze the effect of voltage sag by varying parameters. The Monte Carlo simulation method and the historical reliability data in KEPCO are used for case studies.

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Analysis on Voltage Sag According to Impedance and Application Location of SFCL with Recloser-Recloser Coordination (재폐로차단기간 보호협조 동작시 초전도한류기 적용위치 및 임피던스에 따른 순간저전압 분석)

  • Kim, Yi-Gwan;Noh, Shin-Eui;Kim, Jin-Seok;Kim, Jae-Chul;Lim, Sung-Hun;Kim, Hye-Rim
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.2
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    • pp.230-236
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    • 2014
  • Superconducting fault current limiter (SFCL) has been expected as one of more effective solutions for decreasing fault current instantaneously and various types of SFCLs have been developed to apply into real power system. Recently, the application of the SFCL in a power distribution system has been reported to be contributed to the suppression of the voltage sag as well as the limitation of the fault current. However, the suppressing effect of voltage sag by the SFCL depends on component of its impedance and its application location in a power distribution system considering the recloser-recloser coordination. This paper analyzed the voltage sag caused by recloser-recloser coordination in a power distribution system and the suppression of the voltage sag due to the application location of the SFCL in a power distribution system was discussed through the PSCAD/EMTDC simulation.