• Title/Summary/Keyword: Reactive power compensator

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Static Var Compensator Using Current Source PWM Converter (전류형 PWN 콘버어터의 희한 정지형 무효전력 보상장치에 관한연구)

  • 김철우;권순재;김광태
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.11
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    • pp.1183-1190
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    • 1990
  • In this paper, instantaneous reactive power compensation algorithm is proposed and analyzed. The static Var generator developed in this paper is the current source PWM converter using hysteresis comparator method, which compensates the reactive power by detecting each instantaneous phase voltage and line current, independently. Some aspects on the static Var compensator-such as inductance, capacitance, hysteresis width, and switching frequency, etc.-are discussed. The dynamic performances are examined through digital simulation and experimental test.

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Active/Reactive Compound Compensation in Distribution System

  • Sul, Yong-Tae
    • Journal of Electrical Engineering and information Science
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    • v.2 no.4
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    • pp.46-52
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    • 1997
  • In this paper th use of compensation based on a combination of active plus reactive power at distribution model system is proposed. The basic voltage-power relationships for the linearized case on an infinite bus are used and the compensation angle is defined based on the voltage magnitude response to small power injection. Compensation is supplied at several locations, and the system is subjected to varying fault scenarios, with its response observed under different system conditions. As number of control issues for a storage-based active/reactive power compensator as a bus voltage regulator are explored to compare the effectiveness of active/reactive again reactive-only compensation.

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New Reactive-Power Compensator using Thyristor Current-Source Inverter (싸이리스터 전류원인버터를 이용한 새로운 무효전력보상기)

  • Baek, Seung-Taek;Han, Byeong-Mun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.4
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    • pp.219-225
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    • 1999
  • This paper proposes a new reactive-power compensator composed of a thyristor current-source inverter. The compensator consists of a 6-pulse thyristor bridge, dc reactor, and a commutation circuit. The commutation circuit offers the thyristor bridge to have PWM operation with minimal switching losses. The operation of proposed system was analyzed by computer simulations with EMTP and experimental works with hardware scaled-model. The proposed system would have low cost and easy expansion of operation voltage due to using the conventional thyristors.

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Instantaneous Active/Reactive Power Compensation of Distribution Static Compensator using State Observer (배전용 정지형 보상기의 상태관측기를 이용한 순시 유효/무효전력 보상)

  • Kim, Hyeong-Su;Choi, Jong-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.8
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    • pp.1377-1382
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    • 2008
  • DSTATCOM(distribution static compensator) is one of the custom power devices, and protects a distribution line from unbalanced and harmonic current caused by non-linear and unbalanced loads. Researches about DSTATCOM are mainly divided two parts, one is the calculation of compensation current and the other part is the current control. Conventional researches use a LPF(low pass filter) to eliminate ripple component at the calculation of compensation current. But this method has a problem that LPF's characteristics restrict the compensation performance of instantaneous active and reactive power. This paper proposes a calculation of compensation current using state observer that can be a counterproposal of conventional methods using LPF. Improved performance of instantaneous active and reactive power compensation was shown by experiments.

Series Line Compensation through Voltage Source Inverter (전압원 인버터에 의한 선로의 직렬보상)

  • 한병문;한경희;신익상;강중구
    • Proceedings of the KIPE Conference
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    • 1997.07a
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    • pp.299-302
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    • 1997
  • This paper describes a dynamic var compensator to compensate the line reactance for power transmission and distribution system. The compensator consists of a voltage source inverter with dc capacitor, coupling transformers, and control circuit. The operation of compensator was verified by computer simulations with EMPT and experimental works with a scaled hardware model. The advantage of the proposed system is rapid and continuous regulation of the reactive power.

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Instantaneous Reactive Power Compensator using Current Controlled PWM Converter (전류제어형 PWM 컨버터에 의한 순시 무효전력 보상장치)

  • 최재호;김상훈;박민호
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.7
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    • pp.539-548
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    • 1989
  • This paper describes an instantaneous reactive power compensator aimed at the compensation of reactive power and current harmonics of a thyristor load. A new definition of the instantaneous reactive power consisting of both displacement of fundamental current and harmonic distortion current is proposed and the physical meaning is investigated from the viewpoint of an instantaneous power flow. The instantaneous reactive power is calculated from the feedback of instantaneous voltage, current and is compensated by the current controlled PWM converter connected in parallel with the load. The PWM converter operates as a high performance current control scheme, because adopts the excellent current controlled PWM technique based on the current deviation vector. Both simulation and experimental results show good compensating performances in steady and transient state.

Multi-Function Distributed Generation with Active Power Filter and Reactive Power Compensator

  • Huang, Shengli;Luo, Jianguo
    • Journal of Power Electronics
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    • v.18 no.6
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    • pp.1855-1865
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    • 2018
  • This paper presents a control strategy for voltage-controlled multi-function distributed generation (DG) combined with an active power filter (APF) and a reactive power compensator. The control strategy is based on droop control. As a result of local nonlinear loads, the voltages of the point of common coupling (PCC) and the currents injecting into the grid by the DG are distorted. The power quality of the PCC voltage can be enhanced by using PCC harmonic compensation. In addition, with the PCC harmonic compensation, the DG offers a low-impedance path for harmonic currents. Therefore, the DG absorbs most of the harmonic currents generated by local loads, and the total harmonic distortion (THD) of the grid connected current is dramatically reduced. Furthermore, by regulating the reactive power of the DG, the magnitude of the PCC voltage can be maintained at its nominal value. The performance of the DG with the proposed control strategy is analyzed by bode diagrams. Finally, simulation and experimental results verify the proposed control strategy.

A Compensator for Lateral Current Reduction Applied to Autonomously Controlled UPSs Connected in Parallel

  • Sato Kazuhide Kazuhide;Kawamura Atsuo
    • Journal of Power Electronics
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    • v.5 no.4
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    • pp.312-318
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    • 2005
  • This paper presents a compensator for reduction of the reactive lateral current in multiple autonomously controlled uninterruptible power supplies (UPS) connected in parallel. This compensator acts directly on the control equation for voltage amplitude and it provides an improved current distribution especially in the case of parallel connection of UPSs with different output power ratings. Observations show that the original control equation for output voltage amplitude is efficient for voltage regulation but it causes great variation of voltage levels. A compensator with the same structure is added to counterbalance the variation caused by the original control equation. Simulations show promising results with the employment of the proposed compensator. Our simulations are confirmed by experimental results using three UPSs with different output ratings and voltage limiters ($1\%$) connected in parallel under various conditions.

Inrush Current Suppression Method of the Reactive Power Compensator by using a Linear Region of the Switch (스위치의 선형영역을 이용한 무효전력보상기의 돌입전류 억제 방안)

  • Park, Seong-Mi;Kang, Seong-Hyun;Park, Sung-Jun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.3
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    • pp.55-64
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    • 2013
  • In this paper, a new topology which can add a small reactor in series to a condenser-bank type reactive power compensator to limit current is proposed. And also the proposed topology can add or remove a power condenser safely without any addition of inrush-current suppression resistance. The proposed method tests variable resistance of the drain source of a switching device which is controlled by gate voltage in a two-way switch with a diode rectifier and FET switch. In other words, the proposed method is a inrush-current suppression method with the structure of variable resistance. In particular, the proposed method creates smooth current without any resonance in inrush-current as well as is not limited by the time of switch on and off.

Electric Arc Furnace Voltage Flicker Mitigation by Applying a Predictive Method with Closed Loop Control of the TCR/FC Compensator

  • Kiyoumarsi, Arash;Ataei, Mohhamad;Hooshmand, Rahmat-Allah;Kolagar, Arash Dehestani
    • Journal of Electrical Engineering and Technology
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    • v.5 no.1
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    • pp.116-128
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    • 2010
  • Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.