• Title/Summary/Keyword: Reactive power compensation

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Power Factor Compensation System based on Voltage-controlled Method for 3-phase 4-wire Power System (3상 4선식 전력계통에서 전압제어 방식의 역률보상시스템)

  • Park, Chul-woo;Lee, Hyun-woo;Park, Young-kyun;Joung, Sanghyun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.8
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    • pp.107-114
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    • 2017
  • In this paper, a novel power factor compensation system based on voltage-controlled method is proposed for 3-phase 4-wire power system. The proposed voltage-controlled power factor compensation system generates a reactive power required for compensation by applying a variable output voltage by a slidac to a capacitor. In conventional power factor compensation system using the capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limited capacity of the capacitors. However, the proposed system compensates the power factor up to 100% without error. In this paper, we have developed a voltage-controlled power factor compensation system and a control algorithm for 3-phase 4-wire power system, and verify its performance through simulation and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

OPERATION MODES ANALYSIS FOR A DVR IN DISTRIBUTION GRIDS

  • Kim, Hyo-Sung;Kim, Pederson John
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.480-483
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    • 2001
  • Recent power quality measurement projects report that voltage sags are the most frequent disturbances in the sites [1]-[4]. DVRs were emerged as the best effective and economic solution for this problem [11]. This paper analyzed the power flow of a DVR in distribution grids. This paper showed various operation modes and boundaries such as inductive operation, capacitive operation, and minimal power operation beside the in-phase compensation.

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A Power Factor Compensator Using a Force-Commutated Cycloconverter (강제 전류 싸이크로 컨버터를 이용한 무효 전력 보상)

  • Jung, Yon-Tack;Seo, Young-Soo;Lim, Young-Bae;Kim, Soung-Gi;Hwang, Jun-Ha
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.770-772
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    • 1993
  • This paper is a study of a reactive-power compensator. It make using Power-MOSFET that be little quantity driving-power, easy to control, and be passible to highspeed wich be capable to achieve a reactive power compensator, to get rid of harmonics. On account of having no particular control circuit, composing not need to energy storage element and feedback control compered the previous power transformer in the system organization. It efficiqntly ueed to be in power factor compensation variable load.

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Methodology for Determining of Generator Operation Point for Ensuring Voltage Stability Against Generator Faults in Jeju-Haenam HVDC System

  • Kang, Sang-Gyun;Seo, Sang-Soo;Lee, Byong-Jun;Joo, Joon-Young
    • Journal of Electrical Engineering and Technology
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    • v.5 no.1
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    • pp.54-60
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    • 2010
  • This paper presents a new algorithm for determining generator operation point for maintaining stability considering generator faults in Jeju-Haenam HVDC system. As the HVDC system consumes reactive power for the transmission of active power substantially, compensation of reactive power is essential. And the HVDC system is operated on frequency control mode. That is to say, the HVDC system almost manages system frequency. Therefore, we recognized that the Jeju system could be unstable if the reactive power consumed by the HVDC is insufficient when out-of-step occurs with large generators. When the solution of power flow analysis does not converge due to the unstable system phenomenon, we have difficulty in establishing countermeasures as the post-fault information is not available. In this paper, for the purpose of overcoming this difficulty in establishing countermeasures, we introduce the CPF(Continuation Power Flow) algorithm. This paper suggests an algorithm for calculating the output limitation of the generator to maintain the stability in case of generator fault in the Jeju system.

An Active Power Filter For A Compensation Of Power Factor and Harmonic Currents (역률개선 및 고조파 보상을 위한 능동전력필터)

  • Kim, Yong-Ho;Ahn, Bok-Shin
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.447-450
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    • 1991
  • A novel effective calculation method of the compensation current commands of active power filter using voltage source PWM converter is proposed on the basis of the instantaneous reactive power theory. The load currents and the phase of the source voltages are used for the simplification of the calculations and the reduction of the its time. And the calculation of the currents is performed by DSP 32014 within 50 uSEC. For reducing the DC voltage and saving the costs, a passive power filters are used. The simulation results of the effects of the active power filter with a passive filter are presented.

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Single-Phase Hybrid Active Power Filter Using Rotating Reference Frame (회전좌표계를 이용한 단상 하이브리드형 능동 전력필터)

  • Kim Jin-Sun;Kim Young-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.8
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    • pp.377-386
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    • 2005
  • This paper presents the control algorithm of single-phase hybrid active power filter for the compensation of harmonic current components in nonlinear R-L load with passive active Power filters. To construct two phase system, an imaginary second phase was made. In this proposed method, the new signal which is the delayed through the filtering by the phase-delay property of low-pass filter is used as the secondary phase. Because two-phases have the different phase, the instantaneous calculation of harmonic current is possible. In this paper, a reference voltage is created by multiplying the coefficient k by the compensation current using the rotating reference frame synchronized with the source-frequency, not applying to instantaneous reactive power theory which has been used with the existing fixed reference frames In order to verify the validities of the proposed control methods, experiments are carried out with the prototypes of single-phase hybrid active power filter.

The development study on the power system operation and protection scheme in Myanmar (미얀마 전력계통 운영 및 보호시스템 구축 사업)

  • Kim, Jong-Hwa;Choi, Young-Sung;Han, Seong-Min;Lee, Duck-Jae
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.34-35
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    • 2008
  • KEPCO conducted a third project in Myanmar regarding system operation and protection scheme. This paper deals with blackout reduction plan, reactive power compensation plan and system restoration procedures in operations parts. Moreover protection system improvement plan and standard protection schemes were suggested.

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The Harmonics and Reactive Power Compensation with Series Active Power filter in 3-phase 4-wire System (3상 4선식 전력시스템에서 직렬형 능동필터에 의한 고조파전류와 무효전력 보상에 관한 연구)

  • Kim, Jin-Sun;Kim, Young-Jo;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1072-1074
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    • 2003
  • In this paper, a new control strategy of a series active power filter using direct compensating voltage extraction method is proposed. This control algorithm compensates harmonics, reactive power and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this method is that the compensating voltage of the series active power filter can be extracted without phase transformation. Therefore, calculation time is shorten and the control method is simple compared with conventional method as the p-q theory In addition, this control strategy was applied for the series active power filter in 3-phase 4-wire system which is widely employed in distributing electric energy to several office building and manufacturing plants. Some results obtained from the experimental model using the proposed method are presented to demonstrate and confirm its validity.

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Study on the Calculation of the Optimal Power System Operation Considering Line Contingencies and Line Capacities (선로사고 및 선로용량을 고려한 전력계통 최적운영에 관한 연구)

  • 박영문;백영식;서보혁;신중린
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.9
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    • pp.609-615
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    • 1987
  • The optimal operation of power system is developed by alternately using real power dispatch and reactive power dispatch problem. The real power system scheduling process is formulated as an optimization problem with linear inequality constraints. A.C. loadflow method is used for the problem solution and line losses are considered. The constraints under consideration are generator power limits, load scehdling limits and line capacity limits. In solving the objective function the Dual Relaxation method is adopted. Tests indicate that the method is practical for real time application. The reactive power control problem uses the Dual Simplex Relaxation method as in the real scheduling case. Insted of minimizing the cost of power system, the objective is selected as to determine the highest possible voltage schedule. The constraints under consideration are the voltage limits at each node and the possibilities of supply or absobtion of reactive energy by generator units and the compensation facilities. Tests indicate that the method is practical for real time applications. The overall optimization methods developed in this paper proved to obtained fine results in minimizing object function compared with the method without using voltage control. And the overall voltage profiles were also improved.

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The Optimal Condenser Position & Capacity for Power Factor Compensation in Distribution System (배전계통의 역률보상 콘덴서의 최적 위치 및 용량 산정)

  • Jang, Jeong-Tae;Jeon Young-Soo
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1190-1197
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    • 1999
  • The management of power factor(PF) in the distribution line is treated according to the measurement a month about the feeder unit at the substation. In Korea, we have not researched into power factor in distribution system due to it's less weight. The reactive power in advanced countries is controlled automatically by the compensative condenser switch on/off under the monitoring. This paper first presents the optimal condenser position and proper capacity by lagrangue factor ${\lambda}_{Q}$ which is the line loss index about reactive power unit. Therefore, the largest ${\lambda}_{Q}$ node is the condenser injection point and we find out the best condenser capacity when the line loss is saturated by the moderation of condenser volume. By this method, we suggest 0.6% uprising PF by injection of 15 kVA condenser. Additionally, PF is analysed into 5 areas; large city, middle city, small city, farm village, fishing village by the use of Power Platform which is classified the same concept of the low load management in KEPCO. Two feeders of each area are selected by the worst results of PF in specified areas.

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