• Title/Summary/Keyword: Reactive power compensation

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SVC coupled UPQC for reactive power compensation capacity increase and DC link voltage reduction (무효전력 보상 용량 증대 및 DC 링크 전압 저감을 위한 SVC 결합형 UPQC)

  • Pyo, Soo-Han;Park, Jang-Hyun;Oh, Jeong-Sik;Park, Tae-Sik
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.99-106
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    • 2019
  • This paper propose a new form of UPQC (Unified Power Quality Compensator) to compensate the current and voltage quality problems of nonlinear loads. The conventional UPQC system consists of a series inverter, a parallel inverter, and a common DC link. A new type of UPQC proposed is a parallel compensator with SVC (Static Var Compensator) added to compensate for the wide compensation range and low DC link voltage. The parallel inverter compensates the reactive power generated by the nonlinear load, and the series inverter compensates the sag and swell generated at the power supply side.

Comparison and Study of Active and Hybrid Power Filters for Compensation of Grid Harmonics

  • Gutierrez, Bryan;Kwak, Sang-Shin
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1541-1550
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    • 2016
  • This paper presents a theoretical analysis and comparisons of active power filter (APF) and hybrid power filter (HPF) systems, given terminal constraints of harmonic compensations in nonlinear loads. Despite numerous publications for the two types of filters, the features and differences between them have not been clearly explained. This paper presents a detailed analysis of the operations of a HPF inverter along with those of passive power filters (PPFs). It also includes their effects on the power factor at the grid. In addition, a theoretical analysis and a systematic comparison between the APF and HPF systems are addressed based on system parameters such as the source voltage, output power, reactive component size, and power factor at the grid terminals. The converter kVA ratings and dc-link voltage requirements for both topologies are considered in the presented comparisons

Three-phase Four-wire Series Active Power Filter Control Strategy for The Compensation of Harmonics and Reactive Power Based-on Direct Compensating Voltage Extraction Method (직접 보상전압 추출기법을 이용하여 고조파전류와 무효전력을 보상하는 3상 4선식 직렬 형 능동전력필터의 제어법)

  • 김진선;김영석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.9 no.3
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    • pp.213-221
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    • 2004
  • In recent years, since more and more diode rectifiers with smoothing dc capacitor are used in electronic equipments, household appliances and ac drives, harmonics generated by these loads have become a major issue. In addition, 3-phase 4-wire system is widely employed in distributing electric energy to several office building and manufacturing plants. This systems show excessive currents in the neutral. These neutral currents are fundamentally third harmonic, and their presence is tied to wiring failure, elevating of neutral potentials, transformer overheating, etc. In response to the concerns, this paper proposes a series active power filter scheme based on direct compensating voltage extraction method and the advantage of this control algorithm is direct extraction of compensation voltage reference without multiplying gain. Therefore, the calculation of the compensation voltage reference will becom much simpler than other control algorithm. To verify the effectiveness of the proposed algorithm, a prototype active power filter is built and some experiments are carried out.

Securing Operation Margin Capacity as Coordination Control among the Power Compensation Equipments (전력보상설비의 상호 협조제어에 따른 운영여유용량의 확보)

  • Lee, Sang-Deok;Baek, Young-Sik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.6
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    • pp.1011-1016
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    • 2010
  • It is an important issue to electric power system operations that it can reliably supply large-capacity power to consumption area as due to increasing power demand growth. For this purpose, The FACTS equipment based on Power IT technology with the existing mechanical compensators has been applied to power system. Therefore we suggest on this paper that a plan for coordination control of multiple power compensation equipment in order to increase the utilization of each facility and secure operation margin capacity. As the result of simulation, it is possible to cope actively with a suddenly changed power system. This helps greatly for the voltage stability and supply reliability in a suddenly changed power system.

Series Active Power Filters for Source Voltage Unbalance Compensation and Power Factor Correction (전원 불평형과 역률을 보상하는 직렬형 능동전력필터)

  • Jang, Jeong-Ik;Lee, Dong-Choon;Seok, Jul-Ki
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.498-500
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    • 2005
  • This paper presents a unified control scheme for series-type active power filters combined with shunt passive filters for the source voltage unbalance compensation and the power factor correction simultaneously. The power factor correction is achieved by controlling the amplitude of reactive power current in a series filter as zero in a synchronously rotating reference frame. The proposed algorithm successfully compensates the source voltage unbalance and the power factor. The validity of the proposed scheme has been verified by simulation for a 3-kVA hybrid active power filter system.

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Key Application Technologies of High Efficiency Power Quality Control Systems

  • Liu, Ding-Guo;Shuai, Zhi-Kang;Tu, Chun-Ming;Cheng, Ying;Luo, An
    • Journal of Power Electronics
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    • v.13 no.3
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    • pp.458-468
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    • 2013
  • Large capacity reactive power compensation and harmonic control in the low-voltage grid of an enterprise, are important technical means to improve power quality and reduce power loss. In this paper, the principle of an efficient power quality controller is analyzed. Then, key application technologies of the HPQC which would influence the performances of the HPQC are studied. Based on an analysis of the harmonic shunt problem, a frequency dividing control strategy of the HPQC continuous subsystem is proposed. A parameter design method of the HPQC discrete subsystem and its installation method are also proposed to ensure the system compensation effect. HPQC systems have been designed for a copper foil plant. The effectiveness of this paper has been verified by the simulation and application results.

Accurate Power Sharing in Proportion for Parallel Connected Inverters by Reconstructing Inverter Output Impedance

  • Huang, Shengli;Luo, Jianguo
    • Journal of Power Electronics
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    • v.18 no.6
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    • pp.1751-1759
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    • 2018
  • This paper presents parallel-connected inverters to achieve accurate proportional power sharing. Due to line impedance mismatch, reactive power cannot be distributed proportionally when using the conventional $P-{\omega}$ and $\mathcal{Q}-E$ droop. In order to realize reactive proportional power sharing, the ratio of the droop coefficients should be inversely proportional to their power-sharing ratios. Meanwhile, the ratio of the line impedance should be inversely proportional to the desired power-sharing ratio, which is very difficult to be met in practice. In order to deal with this issue, a practical control strategy is presented. By measuring the PCC voltage and using the virtual impedance, the output impedance of individual inverters is reconstructed to counteract the line impedance effect. In order to guarantee system stability, a low pass filter is designed to suppress the bandwidth of the line compensation. Finally, the simulation and experimental results are given to verify the effectiveness of the proposed control strategy.

A Simple Instantaneous Power Theory and Modified Compensation Performance Evaluation of Active Power Filters (능동전력필터의 간단한 순시전력이론과 수정된 보상성능 평가법)

  • Jung, Y.G.;Yoo, K.H.;Kim, Y.C.;Yang, S.H.;Kim, W.Y.;Lim, Y.C.
    • Proceedings of the KIEE Conference
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    • 1999.07f
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    • pp.2549-2552
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    • 1999
  • The fictitious power theory in time domain is very easy to understand, but power analyzing time of active power is increased, because power is analyzed using signal techniques based on the correlation between voltage and current waveforms. Also, conventional methods in time/frequency domain to evaluate the compensation performance of active power filters are not provided easy solutions. So, the authors have previously proposed 3-D current coordinates which is composed into active component, fundamental reactive component and distorted component of nonlinear loads current. This method has excellent performance, but can not evaluate the characteristics of nonlinear load current whether inductive or capacitive. Therefore, To overcome problems mentioned previously, this paper deals with the simple instantaneous power theory and the modified 3-D current coordinates for evaluating the compensation performance of active power filters. To confirm the validity, active power filters simulator is developed using C-language. From the simulation, results are discussed their utility.

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Modeling and Simulation Reactive Power Compensator using Multi-port Network Algorithm in Electrified Railway (다단자망 알고리즘을 이용한 급전시스템의 무효전력 보상 모델링 및 시뮬레이션)

  • Kim, Joorak
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.5
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    • pp.883-887
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    • 2016
  • The power supply system in Korean electrified railway has adopted AT feeding. If a fault occurs in some substation for any reason, the vicinity substation must feed electric power on the outage substation through catenary. So, the feeding distance grows twice of the normal state at extended feeding condition. If substation's feeding distance is longer than normal condition, the catenary impedance and train to supply electric power from the substation. Therefore, the severe voltage drop can occur and power supply shall be not allowed. This paper presents the model of compensator against voltage drop using multi-port network algorithm. Whole traction power supply system can be analyzed with this model. Computer simulation including this model is performed based on real train schedule and increased schedule in case studies.

Analysis and Design of Utility Interactive Photovoltaic System with Source Side VAR Compensation (전원측 무효전력 보상기능을 갖는 계통연계형 태양광 발전 시스템의 해석 및 설계)

  • 이상용;고재석;한찬영;이정락;최규하;목형수
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.591-594
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    • 1999
  • The application field of photovoltaic system has been increased widely. In the application of photovoltaic system, the utility interactive photovoltaic system(UIPVS) has benefits of not only the home energy saving in domestic system but also reduction of peak power which threaten the capacity of power plant equipment when the maximum power consumption is occurred in daytime. This paper represents the effect of the nonlinear AC load which connected to the UIPVS with parallel connection and introduces the active power filtering(APF) techniques to the UIPVS for the reactive power compensation. The enhancement of source side power quality using APF algorithm is verified using simulation.

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