• Title/Summary/Keyword: 3-phase 4-wire system

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A Novel Series Active Power Filter for Harmonic Reduction of 3-Phase 3-Wire/4-Wire System (3상 3선/4선식 전력계통의 고조파 저감을 위한 새로운 직렬형 능동 필터 시스템)

  • Kim, Myoung-Hyun;Lim, Seung-Won;Han, Yoon-Seok;Kim, Young-Seok;Won, Chung-Yuen;Choi, Se-Wan
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.349-351
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    • 1999
  • This paper presents a new control algorithm for series active power filters that are applied to 3-phase 3-wire and 3-phase 4-wire systems with capacitive loads. It is difficult to reduce harmonic currents in neutral lines of the 3-phase 4-wire systems using conventional series active power filter control methods. 3-phase 4-wire series active power filter systems using the proposed method in this study lower neutral line harmonics. Simulation was carried out to verify the algorithm.

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Characteristics Analysis of 3-phase Induction Generator at the Unbalanced Load Operation (불평형 부하 운전시 3상 유도발전기 특성 해석)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.56 no.3
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    • pp.123-128
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    • 2007
  • Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.

A New Control Method of Series Active Power Filter with Harmonic Voltage Source (고조파 전압원에 대한 직렬형 능동전력필터의 새로운 제어법)

  • Ko, Soo-Hyun;Shin, Jae-Hwa;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1033-1036
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    • 2002
  • This paper introduces a control method of series active power filter that compensate harmonic currents and eliminate a neutral line current in 3 phase 3 wire and 3 phase 4 wire power system with harmonic voltage source. These harmonic currents and neutral line current are caused by a nonlinear loads such as diode rectifiers and thyristor converters. Proposed methode extracts a voltage reference directly from performance function without phase transformation. Therefore, the control method is simpler than any other conventional methods. Experimental results for 3-phase 3-wire and 3-phase 4-wire series active power filter system were shown to verify the effectiveness of this control method.

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Comparative Analysis of Voltage Unbalance Factor on the use of Linear and Non-linear loads in Three-phase Four-wire Low Voltage Distribution Line (3상 4선식 저압 배전선로에서 선형 및 비선형 부하의 사용시 전압 불평형률 비교 분석)

  • Kim, Jong-Gyeum;Kim, Ji-Myeong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.3
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    • pp.587-592
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    • 2017
  • In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

The Analysis of Zero Sequence Components in Dynamic Voltage Restorer System (영상성분을 고려한 DVR 기기 해석)

  • Jeong, Il-Yeop;Park, Sang-Yeong;Won, Dong-Jun;Mun, Seung-Il;Park, Jong-Geun;Han, Byeong-Mun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.4
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    • pp.169-174
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    • 2002
  • The magnitude and phase of the compensating voltage in Dynamic Voltage Restorer (DVR) system depend on the voltage sag in the phases affected by the fault and on the influence of the zero sequence components. If the delta connection of the transformer is used, the zero sequence components do not appear on the load side. But nowadays, Y connected transformers with grounded neutral, that is 3-phase 4-wire system, are usually used. Therefore the zero-sequence components are occurred during faults. The zero-sequence components result in the high insulation costs and the asymmetry of the phase and magnitude of the terminal voltages. In this paper 3 phase 4 wire distribution system and 3 phase 3 wire system are analyzed and characteristics of voltage sag are presented. And this paper proposes the method that can mitigate the zero-sequence under the unbalance faults causing voltage sage and phase angle iumps.

The measurement & Analysis of Voltage, Current and Load Unbalance Factor at Three Phase Four Wire Load System (3상 4선식 부하설비의 전압, 전류 및 부하 불평형율 측정 분석)

  • Kim, Jong-Gyeum;Park, Young-Jeen;Lee, Dong-Ju;Lee, Jong-Han;Jeong, Jong-Ho;Lee, Eun-Woong
    • Proceedings of the KIEE Conference
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    • 2005.04a
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    • pp.28-30
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    • 2005
  • This paper presents a scheme on the characteristics of voltage and current unbalance factor under the load variation at the three phase 4-wire system. The voltage unbalance factor of the three-phase 4-wire system is approved by the field measurement. This system is composed of three one-phase transformer with each other capacity. Current unbalance factor is measured by the power quality measurement apparatus and compared by the load unbalance factor. Each phase has an impedance each other by the unbalanced load operation pattern and give rise to voltage unbalance.

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H-Bridge VSC with a T-Connected Transformer for a 3-Phase 4- Wire Voltage and Frequency Controller of an Isolated Asynchronous Generator

  • Kasal, Gaurav Kumar;Singh, Bhim
    • Journal of Power Electronics
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    • v.9 no.1
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    • pp.43-50
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    • 2009
  • This paper deals with a novel solid state controller (NSSC) for an isolated asynchronous generator (IAG) feeding 3-phase 4-wire loads driven by constant power prime movers, such as uncontrolled pico hydro turbines. AC capacitor banks are used to meet the reactive power requirement of the asynchronous generator. The proposed NSSC is realized using a set of IGBTs (Insulated gate bipolar junction transistors) based current controlled 2-leg voltage source converters (CC- VSC) and a DC chopper at its DC bus, which keeps the generated voltage and frequency constant in spite of changes in consumer loads. The neutral point of the load is created using aT-configuration of the transformers. The IAG system is modeled in MATLAB along with Simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of the isolated generating system consisting of NSSC and IAG driven by uncontrolled pico hydro turbine and feeding 3-phase 4-wire loads.

Anti-Windup Scheme to Control DC Voltage of Three-Phase Four-Wire Active Power Filter (누적방지 기법을 적용한 3상 4선식 능동전력필터 시스템의 직류전압 제어)

  • 정교범
    • The Transactions of the Korean Institute of Power Electronics
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    • v.8 no.2
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    • pp.128-136
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    • 2003
  • This paper investigates the application of the anti-windup scheme to control U voltage of the three-phase four-wire active power filter, installed in a three-phase four-wire power system. In order to reduce efficiently the harmonic currents caused by the switching loads and to improve the whole performance of the flower system, the DC voltage of the three-phase four-wire active power filter should be properly controlled. PI controller can be applied to the U voltage controller of the three-phase four-wire active power filter. However, a large error input to PI controller leads to a windup phenomenon which deteriorate the dynamic characteristics of the U voltage controller Therefore, the application of the anti-windup scheme for the DC voltage controller is proposed and the improved performances of the anti-windup U voltage controller are proved through the computer simulation study.

Characteristics Analysis of Induction Motor by Operation of Non- linear Loads under the 3-phase 4-wire grid system (3상 4선식에서 비선형 부하의 운전시 유도전동기의 특성 해석)

  • Kim, Jong-Gyeum;Park, Young-Jeen;Lee, Eun-Wong
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.43-48
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    • 2006
  • This paper presents a scheme on the characteristics of induction motor under the combination of linear & non-linear loads at the three phase 4-wire power distribution system. Under the combination operation of single & three phase load, voltage unbalance will be generated and current unbalance will be more severe by the dropped voltage quality. All power electronic converters used in different types of electronic systems can increase harmonic disturbances by injecting harmonic currents directly into the feeder grid of three phase 4-wire. Harmonic current may cause torque to decrease. Moors may also overheat or become noisy and torque oscillation in the rotor can lead to mechanical resonance and vibration.

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Comparison of Voltage Unbalance Factor for Line and Phase Voltage (선간전압과 상전압에 대한 전압불평형율의 비교)

  • Kim Jong-Gyeum;Park Young-Jeen;Lee Eun-Woong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.9
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    • pp.403-407
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    • 2005
  • Most of the loads in industrial power distribution systems are balanced and connected to three power systems. However, voltage unbalance is generated at the user's 3-phase 4-wire distribution systems with single & three phase. Voltage unbalance is mainly affected by load system rather than power system. Unbalanced voltage will draws a highly unbalanced current and results in the temperature rise and the low output characteristics at the machine. It is necessary to analyse correct voltage unbalance factor for reduction of side effects in the industrial sites. Voltage unbalance is usually defined by the maximum percent deviation of voltages from their average value, by the method of symmetric components or by the expression in a more user-friendly form which requires only the three line voltage readings. If the neutral point is moved by the unbalanced load at the 3-phase 4-wire system. Line and phase voltage unbalance leads to different results due to zero-sequence component. So that it is difficult to analyse voltage unbalance factor by the conventional analytical method, This paper presents a new analytical method for phase and line voltage unbalance factor in 4-wire systems. Two methods indicate exact results.