• Title/Summary/Keyword: Current Total Harmonic Distortion

Search Result 202, Processing Time 0.027 seconds

Even Harmonic Analysis of Series Arc-fault Current Using BPF of GIC Application in Computer (GIC 적용 대역통과필터를 이용한 컴퓨터 부하의 직렬 아크고장 전류 우수고조파 분석)

  • Ko, Won-Sik;Moon, Won-Sik;Bang, Sun-Bae;Kim, Jae-Chul
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.10
    • /
    • pp.1554-1560
    • /
    • 2012
  • In this paper, the even harmonic current(2nd, 4th, 6th, 8th) of the arc fault current and normal current were measured in computer load and analyzed. The BPF with GIC was developed to detection of harmonic, the exact center frequency and a high degree of sharpness could be easily obtained. The total even harmonic distortion due to series arc fault in computer load was 31.2%, this value was increased 3.9 times better than the total even harmonic distortion of normal current. The results of analysis of arc fault current RMS variation rate and Peak variation rate per half-cycle, The RMS average variation rate are as follows ; the 2nd harmonic was 0.24, the 4th harmonic was 0.15, the 6th harmonic was 0.19, the 8th harmonic was 0.25, respectively. The Peak average variation rate are as follows ; the 2nd harmonic was 0.19, the 4th harmonic was 0.12, the 6th harmonic was 0.13, the 8th harmonic was 0.15, respectively. The results of this analysis utilize data to detect of series arc fault on wiring of computer load.

Harmonic Current Compensation Using Active Power Filter Based on Model Predictive Control Technology

  • Adam, Misbawu;Chen, Yuepeng;Deng, Xiangtian
    • Journal of Power Electronics
    • /
    • v.18 no.6
    • /
    • pp.1889-1900
    • /
    • 2018
  • Harmonic current mitigation is vital in power distribution networks owing to the inflow of nonlinear loads, distributed generation, and renewable energy sources. The active power filter (APF) is the current electrical equipment that can dynamically compensate for harmonic distortion and eliminate asymmetrical loads. The compensation performance of an APF largely depends on the control strategy applied to the voltage source inverter (VSI). Model predictive control (MPC) has been demonstrated to be one of the effective control approaches to providing fast dynamic responses. This approach covers different types of power converters due to its several advantages, such as flexible control scheme and simple inclusion of nonlinearities and constraints within the controller design. In this study, a finite control set-MPC technique is proposed for the control of VSIs. Unlike conventional control methods, the proposed technique uses a discrete time model of the shunt APF to predict the future behavior of harmonic currents and determine the cost function so as to optimize current errors through the selection of appropriate switching states. The viability of this strategy in terms of harmonic mitigation is verified in MATLAB/Simulink. Experimental results show that MPC performs well in terms of reduced total harmonic distortion and is effective in APFs.

A study On the Switching Technique of Boost Converter for Harmonic Reduction (부스트컨버터의 고조파저감을 위한 스위칭 기법에 관한 연구)

  • Shon, Jin-Geun;Chu, Sun-Nam;Kim, Young-Hyuk;Lee, Sang-Cheol;Lee, Bok-Yong
    • Proceedings of the KIEE Conference
    • /
    • 2000.07e
    • /
    • pp.74-78
    • /
    • 2000
  • In this paper a switching control circuit for shaping the line current and reducing the total harmonics distortion in the boost converter is presented. To solve the problems of performance degradation due to pulse waveform in the input current, the boost converter in which the harmonic distortion in the input current is reduced using a 3th harmonic-injected PWM is proposed. Finally, Simulation and experimental results of boost converter with 5[kHz] switching frequency are presented and correction of power factor and reduction of total harmonic distortion was established.

  • PDF

Comparison of the harmonic reduction by using harmonic passive fitters and technique of intervene firing method at the pulse of the 6-pulse phase controlled converter.

  • Wongtongdee, Surached W.;Laohasongkram, Pipat
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.782-785
    • /
    • 2005
  • This article introduces technique to reduce harmonic by using the $5^{th}$ and $7^{th}$ harmonic tune filter and line reactor in the comparison to the technique of intervening firing method at the pulse of the 6-pulse phase-controlled converter in every 1/6 period. The design of the technique introduced in this article is to reduce the harmonic distortion of the current and the voltage resulted from three-phase thyristor phase-controlled converter. The waveform obtained from the experiment was analyzed on the spectrum of the current, voltage and the total harmonic distortion. The double firing method causes zero vectors of output voltage and input current. Designing the mechanism of the converter based on the idea of Park Vector Theory, the number of harmonic distortion in the intervening firing method were compared to those in normal firing method.

  • PDF

Control Method for Reducing the THD of Grid Current of Three-Phase Grid-Connected Inverters Under Distorted Grid Voltages

  • Tran, Thanh-Vu;Chun, Tae-Won;Lee, Hong-Hee;Kim, Heung-Geun;Nho, Eui-Cheol
    • Journal of Power Electronics
    • /
    • v.13 no.4
    • /
    • pp.712-718
    • /
    • 2013
  • This paper proposes a control method for reducing the total harmonic distortion (THD) of the grid current of three-phase grid-connected inverter systems when the grid voltage is distorted. The THD of the grid current caused by grid voltage harmonics is derived by considering the phase delay and magnitude attenuation due to the hardware low-pass filter (LPF). The Cauchy-Schwarz inequality theory is used in order to search more easily for the minimum point of the THD. Both the gain and angle of the compensation voltage at the minimum point of the THD of the grid current are derived with the variation of cut-off frequencies of the hardware LPF. Simulation and experimental results show the validity of the proposed control methods.

A Study on Harmonics Analysis and Modelling for Distribution System (배전 시스템의 고조파 분석 및 모델링에 관한 연구)

  • Wang, Yong-Peel;Jeong, Jong-Won;Jeong, Dong-Il
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.21 no.3
    • /
    • pp.62-68
    • /
    • 2007
  • The increasing use of power electronic equipment in distribution system has been the reason for the greater concern about a harmonic in recent time. Therefore, it is necessary for measurement and modelling to analyze a harmonic level and a transfer characteristic in distribution system. In this paper, the Point of Common Coupling (PCC) is selected to analyze harmonic characteristic of distribution system by IEC 61000-3-6. Harmonic voltage and orient were measured at the PCC of real distribution system Harmonic distribution, nonlinear load component and Total Harmonic Distortion(THD) were verified. The effective and accurate modelling of real distribution system were proved through a analysis of harmonic impedance, voltage and current under steady-state. Harmonic transfer characteristic were investigated through a analysis of harmonic voltage and current under harmonic current source.

On-line Harmonic Distortion Index for Power Quality Assessment (온라인 고조파 해석 지수의 개발)

  • Jang, Gil-Soo;Song, Hwa-Chang;Lee, Byong-Jun
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.50 no.8
    • /
    • pp.373-378
    • /
    • 2001
  • This paper introduces a new online index to quantify the harmonic distortion. The proposed index based on VI product can represent the harmonic distortion of both voltage and current, and it includes the effect of interharmonic distortion. Also, the new index is suitable to online harmonic distortion evaluation since it only requires the r.m.s. (root mean square) value and fundamental frequency value of the signals. Case studies are presented to show the availability of the proposed index using the comparison with the THD (Total Harmonic Distortion).

  • PDF

A New Assessment for the Total Harmonic Contributions at the Point of Common Coupling

  • Han, Jong-Hoon;Lee, Kyebyung;Song, Chong Suk;Jang, Gilsoo;Byeon, Gilsung;Park, Chang-Hyun
    • Journal of Electrical Engineering and Technology
    • /
    • v.9 no.1
    • /
    • pp.6-14
    • /
    • 2014
  • A new method to determine the total harmonic contributions of several customers and the utility at the point of common coupling is presented. The proposed method can quantify the individual harmonic impact of each suspicious harmonic source at the point of common coupling. The individual harmonic impact index is then used to assess the total harmonic contribution of each harmonic source. This index can be calculated by the results processed from instantaneous harmonic voltage and current phasor values. The results demonstrate the performance of the proposed method in terms of steady-state accuracy and response to time-varying operating conditions. The proposed index can be used for billing purposes to control harmonic distortion levels in power systems.

A study of Single-phase Voltage Source PWM Converter for High Power Factor (고역률 제어를 위한 단산 전압원 PWM 컨버터에 관한 연구)

  • 류성식;손진근;정을기;김형원;전희종
    • Proceedings of the KIPE Conference
    • /
    • 1999.07a
    • /
    • pp.362-365
    • /
    • 1999
  • In this paper, the method of reducing harmonics and correcting of power factor in single PWM converter associated with diode rectifier and boos converter is studied. The ac-dc converter in which the harmonic distortion in the input current is reduced using a third harmonic injected PWM is proposed. A lower switching power loss and easy configuration o control circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[KHz] switching frequency are presented and correction of power factor and reduction of total harmonic distortion was established.

  • PDF

New Generalized PWM Schemes for Multilevel Inverters Providing Zero Common-Mode Voltage and Low Current Distortion

  • Nguyen, Nho-Van;Nguyen, Tam-Khanh Tu
    • Journal of Power Electronics
    • /
    • v.19 no.4
    • /
    • pp.907-921
    • /
    • 2019
  • This paper presents two advanced hybrid pulse-width modulation (PWM) strategies for multilevel inverters (MLIs) that provide both common-mode voltage (CMV) elimination and current ripple reduction. The first PWM utilizes sequences that apply one switching state at the double ends of a half-carrier cycle. The second PWM combines the advantages of the former and an existing four-state PWM. Analyses of the harmonic characteristics of the two groups of switching sequences based on a general switching voltage model are carried out, and algorithms to optimize the current ripple are proposed. These methods are simple and can be implemented online for general n-level inverters. Using a three-level NPC inverter and a five-level CHB inverter, good performances in terms of the root mean square current ripple are obtained with the proposed PWM schemes as indicated through improved harmonic distortion factors when compared to existing schemes in almost the entire region of the modulation index. This also leads to a significant reduction in the current total harmonic distortion. Simulation and experimental results are provided to verify the effectiveness of the proposed PWM methods.