• Title, Summary, Keyword: Voltage sag

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Three Phase Voltage Sag Compensator Using Three Phase AC/AC Chopper (3상 AC/AC 초퍼를 이용한 3상 Voltage Sag Compensator)

  • Kim, Dong-Kyu;Choi, Nam-Sup
    • Proceedings of the KIPE Conference
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    • pp.144-145
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    • 2014
  • 본 논문에서는 Buck type의 3상 AC/AC 초퍼를 이용한 3상 voltage sag compensator를 제안한다. 제안된 회로는 sag보상 동작 시 사용된 변압기의 누설리액턴스가 3상 PWM Buck AC/AC converter에 미치는 영향이 작아 동작효율이 높고, sag가 발생하지 않은 상태일 때 입력과 출력이 절연되는 장점이 있다. 본 논문에서는 제안된 회로의 동작 및 특성을 설명하고, 타당성을 입증하기 위해 PSIM으로 시뮬레이션 하였다.

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Cascaded Boost Type Inverter System for Compensation of Voltage Sag (Voltage Sag 보상을 위한 종속 승압형 인버터 시스템)

  • Lee, Seung-Yong;Seo, Young-Min;Kim, Myeong-Soo;Hong, Soon-Chan
    • Proceedings of the KIPE Conference
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    • pp.352-353
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    • 2011
  • This paper proposes a cascaded boost type inverter system to compensate the voltage sag. If the voltage sag has appeared in input voltage, a cascaded boost converter would be operated to compensate voltage sag. The output voltage is kept constant by a direct-quadrature frame controller in the single-phase PWM inverter. The validity of proposed system is verified by simulation on the 300W cascaded boost type inverter system.

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Voltage Sag and Swell Estimation Using ANFIS for Power System Applications

  • Malmurugan, N.;Gopal, Devarajan;Lho, Young Hwan
    • Journal of the Korean Society for Railway
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    • v.16 no.4
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    • pp.272-277
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    • 2013
  • Power quality is a term that is now extensively used in power systems applications, and in this context the voltage, current, and phase angle are discussed widely. In particular, different algorithms that are capable of detecting the voltage sag and swell information in a real time environment have been proposed and developed. Voltage sag and swell play an important role in determining the stability, quality, and operation of a power system. This paper presents ANFIS (Adaptive Network based Fuzzy Inference System) models with different membership functions to build the voltage shape with the knowledge of known system parameters, and detect voltage sag and swell accurately. The performance of each method has been compared with each other/other methods to determine the effectiveness of the different models, and the results are presented.

The Study on Detecting Scheme of Voltage Sag using the Two Difference Voltage (이중 차 전압을 이용한 전압 새그 검출 기법에 관한 연구)

  • Lee, Woo-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.12
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    • pp.65-73
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    • 2014
  • In this paper, the detection scheme of the voltage variation using a two difference voltage is proposed. The conventional sag detector is from a single-phase digital phase-locked loop (DPLL) that is based on a d-q transformation using an all-pass filter (APF). The APF generates a virtual q-axis voltage component with $90^{\circ}$ phase delay but the APF cannot generate the virtual q-axis voltage depending on the phase of the grid voltage. To overcome the problem, q-axis voltage component is generated from difference between the current and previous value of d-axis voltage component in the stationary reference frame. However, the difference voltage around the zero crossing is not enough to detect the voltage sag. Therefore, the new detection scheme using the two difference voltage which can detect the sag around the zero crossing voltage is proposed.

Implementation of a Non-Linear Adaptive Filter Based Sag Detection Method for Dynamic Voltage Restorers under Unbalanced Fault Conditions

  • Cuma, M. Ugras;Teke, Ahmet;Meral, M. Emin;Bayindir, K. Cagatay;Tumay, Mehmet
    • Journal of Power Electronics
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    • v.13 no.2
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    • pp.304-312
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    • 2013
  • The most common power quality problems in distribution systems are related to unbalanced voltage sags. Voltage sags must be detected quickly and corrected in a minimum amount of time. One of the most widely used methods for sag detection is based on the d-q transformation. This method has the disadvantage of missing the detection of unbalanced faults, because this method uses a voltage sag level signal obtained from the average of 3 phases for sag detection. In this paper, an adaptive filter sag detection method is proposed for Dynamic Voltage Restorers (DVR) under unbalanced fault conditions. The proposed DVR controller is able to detect balanced, unbalanced and single phase voltage sags. A novel reference voltage generation method is also presented. To validate the proposed control methods, a 3-phase DSP controlling a DVR prototype with a power rating of 1.5-kVA has been developed. Finally, experimental results are presented to verify the performance of the proposed control methods.

Method to Determine Areas of Vulnerability for Calculating Sag Cumulative Table and Sag Density Table (순간전압강하 누적 테이블 및 밀도 테이블 계산을 위한 취약지역 결정 방법)

  • Park, Chang-Hyun;Lee, Hansang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.6
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    • pp.746-751
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    • 2014
  • This paper presents a method to calculate a sag cumulative table and density table based on the area of vulnerability to voltage sags. The expected sag performance at sensitive load points can be easily assessed through the calculation of the sag cumulative table and density table. However, the calculation of the tables regarding large power systems is very difficult task. Therefore, an efficient method for calculating the tables is needed. In this paper, the improved method to determine the areas of vulnerability is addressed and the method to calculate the tables based on the area of vulnerability is also described. The proposed scheme can be efficiently used to assess the voltage sag performance at sensitive load points in large power systems.

Design and Implementation of Low Cost Boost Type Single-Phase Inverter System for Compensation of Voltage Sag (순간전압강하 보상을 위한 저가의 승압형 단상 인버터 시스템의 설계 및 구현)

  • Lee, Seung-Yong;Hong, Soon-Chan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.1
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    • pp.85-92
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    • 2012
  • In this paper, a 300[W] class boost type single-phase inverter system which can compensate voltage sag on source side is designed and implemented. This system is a two-stage conversion system composed of a boost converter and a PWM inverter. If the voltage sag has appeared at the point of common coupling, the boost converter would be operated to compensate it. The boost converter and the inverter were constructed on single smart power module(SPM) to implement low cost system. The system is designed for that the THD of output voltage is below 5[%]. Finally, the validity of the design for the inverter system is verified by both simulations and experiments.

Development of a User-Friendly Application for Voltage Sag Analysis

  • Park Chang-Hyun;Jang Gil-Soo;Kim Chul-Hwan;Kim Jae-Chul
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.145-152
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    • 2006
  • This paper presents a windows application for voltage sag analysis and effective data visualization. The developed Voltage Sag Analysis Tool (VSAT) was designed by using the Object-Oriented Programming (OOP) concept and C++ programming language. The VSAT provides basic functions for voltage sag analysis such as power flow analysis, short circuit analysis and stochastic analysis. In particular, the VSAT provides effective data visualization through computer graphics and animation. Analysis results are expressed realistically and intuitively on geographical display. The Graphic User Interface (GUI) of VSAT was designed specifically for voltage sag analysis. In this paper, the development and implementation of VSAT is presented. In order to demonstrate the capabilities of VSAT, it is used to analyze the Jeju Island power system in South Korea.

Analysis of Voltage Sag on Power Distribution System (배전시스템센서의 순간전압강하 분석)

  • Oh, Jung-Hwan;Rim, Seong-Jeong;Yun, Sang-Yun;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • pp.954-957
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    • 1997
  • In this paper, we analyze the voltage sag caused by reclosing on electric power distribution system. When a fault is on the electric system, a reclosing operation brings a voltage sag on the feeders which is supplied with a common substation transformer. By analyzing the fault wave-form measured in the field, it is showed that a voltage sag is in proportion to a fault current. Also, we propose an adaptive reclosing scheme. This scheme changes the number of reclosing as a function of the magnitude of a fault voltage and the fault type. As the proposed scheme is compared with conventional scheme in the side of voltage sag and permanent fault, it is verified that the proposed scheme is more effective than conventional scheme.

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A Single-Phase Quasi Z-Source Dynamic Voltage Restorer(DVR) (단상 Quasi Z-소스 동적전압보상기(DVR))

  • Lee, Ki-Taeg;Jung, Young-Gook;Lim, Young-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.4
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    • pp.327-334
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    • 2010
  • This paper deals with a single-phase dynamic voltage restorer(DVR) with a quasi Z-source topology. The proposed system based on a single-phase quasi Z-source PWM ac-ac converter which have features such as the input voltage and output voltage are sharing ground, and input current operates in continuous current mode(CCM). For the detection of voltage sag-swell, peak voltage detection method is applied. Also, the circuit principles of the proposed system are described. During the 60% severe voltage sag and 30% voltage swell, the proposed system controls the adding or missing voltage and maintains the rated voltage of sinusoidal waveform at the terminals of the critical loads. Finally, PSIM simulation and experimental results are presented to verify the proposed concept and theoretical analysis.