• Title/Summary/Keyword: Inter-harmonic

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Method Based on Sparse Signal Decomposition for Harmonic and Inter-harmonic Analysis of Power System

  • Chen, Lei;Zheng, Dezhong;Chen, Shuang;Han, Baoru
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.559-568
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    • 2017
  • Harmonic/inter-harmonic detection and analysis is an important issue in power system signal processing. This paper proposes a fast algorithm based on matching pursuit (MP) sparse signal decomposition, which can be employed to extract the harmonic or inter-harmonic components of a distorted electric voltage/current signal. In the MP iterations, the method extracts harmonic/inter-harmonic components in order according to the spectrum peak. The Fast Fourier Transform (FFT) and nonlinear optimization techniques are used in the decomposition to realize fast and accurate estimation of the parameters. First, the frequency estimation value corresponding to the maxim spectrum peak in the present residual is obtained, and the phase corresponding to this frequency is searched in discrete sinusoids dictionary. Then the frequency and phase estimations are taken as initial values of the unknown parameters for Nelder-Mead to acquire the optimized parameters. Finally, the duration time of the disturbance is determined by comparing the inner products, and the amplitude is achieved according to the matching expression of the harmonic or inter-harmonic. Simulations and actual signal tests are performed to illustrate the effectiveness and feasibility of the proposed method.

Power Signal Inter-harmonics Detection using Adaptive Predictor Notch Characteristics (적응예측기 노치특성을 이용한 전력신호 중간고조파 검출)

  • Bae, Hyeon Deok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.10 no.5
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    • pp.435-441
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    • 2017
  • Detecting an inter-harmonic accurately is not easy work, because it has small magnitude, and its frequency which can be observed is not an integer multiple of fundamental frequency. In this paper, a new method using filter bank system and adaptive predictor is proposed. Filter bank system decomposes input signal to sub bands. In adaptive predictor, inter-harmonic is detected with decomposed sub band signal as input, and error signal as output. In this scheme, input-output characteristic of adaptive predictor is notch filter, as predicted harmonic is canceled in error signal, so detecting an inter-harmonic can be possible. Magnitude and frequency of detected inter-harmonic is estimated by recursive algorithm. The performances of proposed method are evaluated to sinusoidal signal model synthesized with harmonics and inter-harmonics. And validity of the method is proved as comparing the inter-harmonic detection results to MUSIC and ESPRIT.

Multiple-Period Repetitive Controller for Selective Harmonic Compensation with Three-Phase Shunt Active Power Filter

  • Zhang, Chao;Gong, Maofa;Zhang, Yijun;Li, Yuxia
    • Journal of Power Electronics
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    • v.15 no.3
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    • pp.819-829
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    • 2015
  • This paper presents a shunt active power filter (SAPF) for compensating inter-harmonics and harmonics when inter-harmonics content is evident in the grid. The principle of inter-harmonics generation in the grid was analyzed, and the inter-harmonics effect on repetitive controllers was discussed in terms of control performance. Traditional repetitive controllers are not applicable in inter-harmonic compensation. Moreover, the effect of an ideal controller on harmonics signals was analyzed on the basis of the internal model principle. The repetitive controller was improved in the form of a basis function according to theoretical analysis. The finite-dimensional repetitive controller, which is also called the multiple-period repetitive controller, was designed for the control of multiple periodic signals. A selective harmonic compensation system was developed with SAPF. This system can be used to compensate harmonics and inter-harmonics in the grid. Finally, system control performance was verified by simulation and experimental results.

Harmonic Reduction of Three Phase Multi-Pulse Converter Circuit without Input Transformer (입력 변압기 없는 3상 멀티-펄스 콘버터의 고조파 저감)

  • Park, Hyun-Chul;Kim, Yeong-Min;Hwang, Jong-Sun;Kim, Jong-Man
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05b
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    • pp.128-131
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    • 2002
  • In this paper, a new method for reducing harmonic in input AC line currents of converter presents, which is the multi-pulse converter circuit without the input transformer. This system can reduce the harmonic like conventional 12-pulse converter. Both the bridge circuits are controlled with the shifted firing angle and connected 2 tap inter-phase reactor. Using 2 tap changing on inter-phase reactor, the input current is controlled with the different two values in order to make the input current waveform 12 pulses.

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Performance Evaluation of One Channel B-WLL IF Receiver System (단일 채널 B-WLL IF 시스템 수신부 성능 분석)

  • 최성연;이창석;전동근
    • Journal of Korea Society of Industrial Information Systems
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    • v.6 no.4
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    • pp.54-60
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    • 2001
  • In this thesis, We analyze performance evaluation of one channel B-WLL IF receiver system. Among the item of receiver performance, inter-modulation interference and yield analysis is especially focused. Since inter-modulation interference cause bad influence on system performance due to unwanted third order harmonic located in desired frequency band, third order harmonic causing inter-modulation interference should be efficiently removed. Yield analysis is observing influence on system performance when system element parameter is statistically varied, and in this thesis, system output is observed for LNA parameters. Additionally, Scheme for LNA gain adjustment to reduce inter-modulation interference is proposed by observing variation of third order harmonic output for LNA gain variation.

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Power System Harmonic Estimation Based on Park Transform

  • Chen, Ya;Ji, Tianyao;Li, Mengshi;Wu, Qinghua;Wang, Xuejian
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.560-574
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    • 2016
  • This paper presents a novel method for power system harmonic estimation based on the Park transform. The proposed method firstly extends the signal to a group of three-phase signals in a-b-c coordinate. Then, a linear fitting based method is adopted to estimate the fundamental frequency. Afterwards, the Park transform is utilized to convert the three-phase signals from a-b-c coordinate to d-q-0 coordinate. Finally, the amplitude and phase of a harmonic component of interest can be calculated using the d-axis and q-axis components obtained. Simulation studies have been conducted using matrix laboratory (MATLAB) and power system computer aided design/electromagnetic transients including direct current (PSCAD/EMTDC). Simulation studies in MATLAB have considered three scenarios, i.e., no-frequency-deviation scenario, frequency-deviation scenario and the scenario in the presence of inter-harminics. The results have demonstrated that the proposed method achieves very high accuracy in frequency, phase and amplitude estimation under noisy conditions, and suffers little influence of the inter-harmonics. Moreover, comparison studies have proved that the proposed method is superior to FFT and Interpolated FFT with the Hanning Window (IpFFTHW). Finally, a popular case in PSCAD/EMTDC has been employed to further verify the effectiveness of the proposed method.

Adaptive Reconstruction of Multi-periodic Harmonic Time Series with Only Negative Errors: Simulation Study

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.26 no.6
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    • pp.721-730
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    • 2010
  • In satellite remote sensing, irregular temporal sampling is a common feature of geophysical and biological process on the earth's surface. Lee (2008) proposed a feed-back system using a harmonic model of single period to adaptively reconstruct observation image series contaminated by noises resulted from mechanical problems or environmental conditions. However, the simple sinusoidal model of single period may not be appropriate for temporal physical processes of land surface. A complex model of multiple periods would be more proper to represent inter-annual and inner-annual variations of surface parameters. This study extended to use a multi-periodic harmonic model, which is expressed as the sum of a series of sine waves, for the adaptive system. For the system assessment, simulation data were generated from a model of negative errors, based on the fact that the observation is mainly suppressed by bad weather. The experimental results of this simulation study show the potentiality of the proposed system for real-time monitoring on the image series observed by imperfect sensing technology from the environment which are frequently influenced by bad weather.

A Linearity Improved Power Amplifier using Bandpass Filter Based on Composite Right-/Left-Handed Structure (CRLH 구조의 대역통과여파기를 이용한 전력증폭기의 선형성 개선에 관한 연구)

  • Kim, Hyoung-Jun;Seo, Chul-Hun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.1
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    • pp.92-96
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    • 2011
  • In this paper, we present a bandpass filter (BPF) based on composite right-/left-handed (CRLH) structure for improving the linearity of the power amplifier. The proposed BPF consist of the inter-digit signal line on the top plane and the complementary split ring resonator (CSRR) on the bottom plane, respectively. The insertion loss is minimized at operation frequency and the 2nd harmonic is suppressed by the bandpass filter using the CRLH structure, respectively. The output power of 33 dBm, the 2nd harmonic of -53.527 dBc, 3rd inter-modulation distortion of -36.16 dBc was obtained at 2.14 GHz, respectively. Compared with the reference power amplifier, the 2nd harmonic of 16 dB and 3rd inter-modulation distortion of 12 dB have been improved at 2.14 GHz, respectively.

Development of the Inter-tidal Exposure Duration Formulae Using Tidal Harmonic Constants (조화상수를 이용한 조간대 노출시간 추정공식 개발)

  • Jeong, Shin Taek;Cho, Hongyeon;Ko, Dong Hui
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.5
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    • pp.319-325
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    • 2012
  • A new formulae for the estimation of the exposure duration in the inter-tidal zone are developed. The exposure duration is one of the most important factors influencing the habitat distribution of the benthic organisms. The formulae can estimate the exposure duration only using the four major tidal harmonic constants available in almost coastal areas. It is easier than the existing method using the frequency analysis of the hourly tidal elevation data. The estimation results by using the formulae suggested in this study are compared with the value by using the observed tidal elevation data analysis in the west coast, Korea. The mean RMS (root-mean squared) errors ranged form 0.8 to 1.4%. It can be used to simply estimate the accurate exposure duration in the region not having the longterm hourly tidal elevation data.

Study on the Measuring of Power Quality for the Residental PV System (가정용태양광 발전설비의 전력품질 측정에 관한 연구)

  • Ahn, Jae-Min;Han, Woon-Ki;Jung, Jin-Soo;Kim, Sun-Gu;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.2176_2177
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    • 2009
  • This paper describe the power quality measuring result of the inter-connected residental PV system. The power quality measuring for inter-connected residental PV system are important to verify their performance and effect of power distribution system with inter-connected residental PV system. Also, these power quality measuring and analysis are essential to improve electrical safety. In order to evaluate influence of power distribution system with inter-connected residental PV system, we measure and analyze power quality index such as power, voltage, current, harmonic, THD, flicker index, power factor and frequency using DEWE5000.

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