• Title/Summary/Keyword: Harmonic

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Harmonic Generation and System Response Characteristics in Electrified Railway(I) - Focused on System Response Characteristics - (전기철도에서의 고조파 발생과 계통응답특성(I) - 계통응답특성을 중심으로 -)

  • Oh Kwang-Hae;Lee Chang-Mu
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.493-498
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    • 2003
  • Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. For these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I ). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II

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Harmonic Generation and System Response Chartcteristics in Electrified Railway(II) - Focused on Measurement and Analysis - (전기철도에서의 고조파 발생과 계통응답특성(II) - 고조파 측정분석을 중심으로 -)

  • Oh Kwang-Hae;Lee Han-Min
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.499-504
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    • 2003
  • Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. For these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I ). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II

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Automatic Classification of Power System Harmonic Disturbances (전력시스템 고조파 외란의 자동식별)

  • Kim, Byoung-Chul;Kim, Hyun-Soo;Nam, Sang-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.7
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    • pp.551-558
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    • 2000
  • In this paper a systematic approach to automatic classificationi of power system harmonic disturbances is proposed where the proposed approach consists of the following three steps:(i) detecting and localizing each harmonic disturbance by applying discrete wavelet transform(DWT) (ii) extracting an efficient feature vector from each detected disturbance waveform by utilizing FFT and principal component analysis (PCA) along with Fisher's criterion and (iii) classifying the corresponding type of each harmonic disturbance by recognizing the pattern of each feature vector. To demonstrate the performance and applicability of the proposed classification procedure some simulation results obtained by analyzing 8-class power system harmonic disturbances being generated with Matlab power system blockset are also provided.

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Parameters On-line Identification of Dual Three Phase Induction Motor by Voltage Vector Injection in Harmonic Subspace

  • Sheng, Shuang;Lu, Haifeng;Qu, Wenlong;Guo, Ruijie;Yang, Jinlei
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.3
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    • pp.288-294
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    • 2013
  • This paper introduces a novel method of on-line identifying the stator resistance and leakage inductance of dual three phase induction motor (DTPIM). According to the machine mathematical model, the stator resistance and leakage inductance can be estimated using the voltage and current values in harmonic subspace. Thus a method of voltage vector injection in harmonic subspace (VVIHS) is proposed, which causes currents in harmonic space. Then the errors between command and actual harmonic currents are utilized to regulate the machine parameters, including stator resistance and leakage inductance. The principle is presented and analyzed in detail. Experimental results prove the feasibility and validity of proposed method.

Analysis of the Harmonic Resonance during Restoration of Primary Restorative Transmission System (시송전계통의 고조파 공진현상에 대한 분석)

  • Lee, Kyeong-Seob;Lee, Heung-Jae
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.5
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    • pp.191-194
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    • 2006
  • Power system restoration following a wide area or complete blackout starts with energizing primary restorative transmission systems. During this primary restoration process, unexpected over-voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. Since the harmonic resonance originates from the nonlinear characteristics, it is very difficult to predict the occurrence of this phenomenon. This paper reports the analyses of the harmonic resonance occurred in domestic power system. Various analyses and results of the harmonic over-voltage is presented based on the PSCAD/EMTDC simulations.

The Design and Implementation of a 5 kW Programmable Three-Phase Harmonic Generator

  • Jeon, Jeong-Chay;Jeon, Hyun-Jae;Choi, Myoung-Il;Park, Chee-Hyun
    • Journal of Electrical Engineering and Technology
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    • v.3 no.2
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    • pp.162-166
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    • 2008
  • This paper presents the design and implementation of a 5kW programmable three-phase harmonic generator, which is capable of generating sinusoidal output voltages with adjustable output amplitude and frequency over a wide range as well as arbitrary waveforms. The considered harmonic generator is a linear power amplifier type. This system consists mainly of a power converter to generate and amplify waveform signals, a controller to control the desired output signal and measure the output parameters including voltage and current, and a control program to set the desired output and display the output values. The prototype programmable three-phase harmonic generator has been constructed and tested. Test results show that the developed programmable three-phase harmonic generator performs well.

Harmonic Analysis of a Modular Multilevel Converter Using Double Fourier Series

  • Quach, Ngoc-Thinh;Chae, Sang Heon;Ahn, Jin Hong;Kim, Eel-Hwan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.298-306
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    • 2018
  • This paper presents a harmonic analysis of the modular multilevel converter (MMC) using a double Fourier series (DFS) algorithm. First, the application of DFS for harmonic calculation in the MMC is made by considering the effect of arm inductor. The analytical results are then confirmed by comparing with the simulation results of using the fast Fourier transform (FFT) algorithm. Finally, distribution of harmonics and total harmonic distortion (THD) in the MMC will be analyzed in three cases: harmonics versus number of levels of MMC, harmonics versus total switching frequency and harmonics versus modulation index. The simulation results are performed in the PSCAD/EMTDC simulation program in order to verify the analytical results obtained by Matlab programming.

Assessment of Harmonic Emission Limits for Customer at HV System (고압 수용가의 고조파 방출 한계 평가)

  • Wang, Yong-Peel;Kim, Se-Dong;Jeon, Young-Soo;Joo, Seok-Min
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.12
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    • pp.110-114
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    • 2008
  • In recent years, the standard for harmonics has established and applied in many countries. However a harmonic management has not performed for the absence of standard and procedure in Korea. For this reason, the standard establishment for harmonic based on the main purpose of international harmonic standards and property of domestic transmission system is required. This paper describes the software of assessment of harmonic emission limit for customer at HV System using Microsoft Excel.

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
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    • v.50 no.8
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    • pp.373-378
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    • 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).

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Analysis of Harmonic Incoming and Outgoing for Transmission System (송전계통 고조파 유입/유출 분석)

  • Wang, Y.P.;Choi, S.Y.;Kwak, N.H.;Jeon, Y.S.;Park, S.H.
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.561-562
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    • 2007
  • A method is proposed in this paper to determine the harmonic contributions of a customer at the point of common coupling. The method can quantify customer and utility responsibilities for limit violations caused by either harmonic source changes or harmonic impedance changes. It can be implemented in current power quality monitors and digital revenue meters. The method is comparison of measurement phase angles between harmonic voltage and current. The proposed method has been applied to the test system. The study results have indicated the accuracy of harmonic injection and emission for customer and utility.

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