Cheng-I Chen

National Central University, Taoyuan City, Taiwan, Taiwan

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Publications (13)33.48 Total impact

  • Cheng-I Chen, G.W. Chang
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    ABSTRACT: Magnitude and duration are important characteristics when performing tracking of voltage variations. Accurate characterization of voltage variations relies much on the precise identification of frequencies of the measured signals. Although the Prony's method can provide high resolution for frequency estimation, the computational burden in the root-finding process is a crucial problem. A modified Prony-based solution procedure for voltage variation tracking is proposed in this paper. By providing a set of filters, the transfer polynomial with high estimation order in Prony's model can be efficiently reduced. The performance of the proposed method is validated by testing the generated and actual measured voltage signals. Results are compared with those obtained by typical Prony's method, namely, fast Fourier transform, adaptive linear neural network, and Kalman filtering. It shows that the proposed method is more accurate regardless of interferences of the power system frequency deviation, harmonics, and interharmonics, where both voltage variations and harmonics can be simultaneously detected.
    IEEE Transactions on Industrial Electronics 01/2013; 60(7):2681-2688. · 6.50 Impact Factor
  • Cheng-I Chen, G.W. Chang
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    ABSTRACT: Selection of a suitable method among various techniques for assessment of harmonic and interharmonic components of a measured voltage or current waveform is not an easy task for the students. A good start is to understand the relationship between the analysis techniques and the measured parameters. In this paper, several commonly used methods for time-varying harmonic and interharmonic detection of measured waveforms are reviewed and implemented in an integrated virtual instrumentation. Compared from the aspect of frequency identification for the reviewed methods, general guidelines for performing harmonic and interharmonic detection are also developed for the educational purpose.
    IEEE Transactions on Industrial Electronics 11/2010; · 6.50 Impact Factor
  • G.W. Chang, Cheng-I Chen
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    ABSTRACT: Frequency is an important factor for power system harmonics measurement. Accurate spectral analysis relies much on the correct identification of frequencies of the measured signals. In this paper, several commonly used methods for power system stationary and time-varying harmonics measurement are reviewed and compared according to the aspect of frequency identification. Recommendations for adopting proper harmonics detection methods under different measuring conditions are then suggested.
    Power and Energy Society General Meeting, 2010 IEEE; 08/2010
  • G.W. Chang, Cheng-I Chen
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    ABSTRACT: Frequency is an important indicator for the quality of electric power. Accurate spectral decompositions rely much on the correct identification of frequencies of the measured signals. An efficient procedure that includes a high-resolution Prony-based method in conjunction with the downsampling technique for harmonics and interharmonics detection of the measured power signal is proposed in this paper. It is shown that even when two or more closely adjacent spectral lines are present, the proposed method can precisely detect the harmonic and interharmonic components. The performance of the proposed method is validated by testing the simulated and actual measured power signals. Results are compared with those obtained by fast Fourier transform with and without synchronization, IEC subgrouping method, and other commonly used linear prediction approaches adopted in the Prony's method. It shows that the proposed method is more accurate on the detection of harmonics and interharmonics with high resolution.
    IEEE Transactions on Power Delivery 08/2010; · 1.52 Impact Factor
  • G.W. Chang, Cheng-I Chen, Yu-Feng Teng
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    ABSTRACT: The widespread application of power-electronic loads has led to increasing harmonic pollution in the supply system. In order to prevent harmonics from deteriorating the power quality, detecting harmonic components for harmonic mitigations becomes a critical issue. In this paper, an effective procedure based on the radial-basis-function neural network is proposed to detect the harmonic amplitudes of the measured signal. By comparing with several commonly used methods, it is shown that the proposed solution procedure yields more accurate results and requires less sampled data for harmonic assessment.
    IEEE Transactions on Industrial Electronics 07/2010; · 6.50 Impact Factor
  • G.W. Chang, Cheng-I Chen, Yu-Jen Liu
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    ABSTRACT: It is known that artificial neural network is a powerful scheme for function learning and modeling nonlinear loads. However, a direct application of artificial neural network for modeling time-varying loads may lead to inaccuracies. This paper presents an accurate neural-network-based method for modeling the highly nonlinear voltage-current characteristic of an ac electric arc furnace (EAF). The neural-network-based model can be effectively used to assess waveform distortions, voltage fluctuations, and performances of reactive power compensation devices associated with the EAF in a power system. Simulation results obtained by using the proposed model are compared with the actual measured data and two other traditional neural network models. It is shown that the proposed method yields favorable performance and can be applied for modeling similar types of nonlinear loads for power engineering studies.
    IEEE Transactions on Power Systems 03/2010; · 2.92 Impact Factor
  • G. W. Chang, Cheng-I Chen
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    ABSTRACT: Effective detection of power quality events is an important issue for maintaining reliable operations of power systems. Under different measuring environment, detection methods usually need different requirements. In this paper, the performances of several commonly seen methods for the detection of voltage sags are evaluated and compared.
    01/2010;
  • Cheng-I Chen, Gary W. Chang
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    ABSTRACT: The widespread application of power electronic loads has led to increasing harmonic pollution in the supply system. In order to prevent harmonics from deteriorating the power quality, detecting harmonic components for harmonic mitigations becomes a critical issue. In this paper, an effective procedure based on the radial basis function neural network is proposed to detect harmonic amplitudes of the measured signal. By comparing with several commonly used methods, it is shown that the proposed solution procedure yields more accurate results and requires less sampled data for harmonics assessment.
    01/2010;
  • Cheng-I Chen, G.W. Chang
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    ABSTRACT: Power quality indices are important parameters to assess the operation of a power system. Though there are many power quality indices defined in the literature, the actual operation status of the system is still difficult to observe in some practical applications with the given indices. In this paper, several commonly used and recently proposed power quality indices for harmonic assessment are discussed, and the application challenges for the defined indices are also addressed. It is expected that the investigation can contribute for future developments of harmonics monitoring and mitigation strategies.
    Power & Energy Society General Meeting, 2009. PES '09. IEEE; 08/2009
  • G.W. Chang, Cheng-I Chen, Ya-Lun Huang
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    ABSTRACT: Voltage fluctuations caused by rapidly changing loads in the power systems may give rise to noticeable illumination flickers of lighting equipment. The voltage flickers can also cause malfunctions in many electric devices. This paper presents a digital implementation of flickermeter in the hybrid time and frequency domains based on IEC standard 61000-4-15. In addition, this paper proposes a new demodulation method to extract the voltage envelope. Simulations and actual measurements show that the digital implementation with the proposed method yields relatively accurate flicker measurements.
    IEEE Transactions on Power Delivery 08/2009; · 1.52 Impact Factor
  • G.W. Chang, Cheng-I Chen, Quan-Wei Liang
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    ABSTRACT: Harmonics and interharmonics may introduce operational problems in electrical and electronic equipment. Therefore, monitoring harmonics/interharmonics for improving the power quality is of importance for both electric utilities and their customers. In this paper, a cascaded two-stage adaptive linear element (ADALINE) structure for both harmonics and interharmonics measurement is proposed. In addition, a simple laboratory setup implemented by MATLAB and the dedicated hardware for measuring power signals is built to verify the performance of proposed method. Results are compared with those obtained by short-time Fourier transform and two other conventional ADALINE-based methods. It shows that the proposed method is with a better accuracy, even if the power frequency deviation and interharmonic components are present in the measured signal. The proposed method also can be adopted for harmonic/interharmonic compensation devices in real time.
    IEEE Transactions on Industrial Electronics 07/2009; · 6.50 Impact Factor
  • Cheng-I Chen, G.W. Chang
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    ABSTRACT: In this paper an efficient technique based on Prony's method for the time-varying power system harmonic estimation is proposed. Although the high frequency resolution is the major advantage of Prony's method, the great computational burden with the high estimation order usually makes it only suitable for the off-line analysis. To achieve the fast harmonic measurement, a filter-bank structure is proposed to reduce the above computational complexity. Finally, the measurement results are reported to verify the performance of the proposed technique.
    Circuits and Systems, 2009. ISCAS 2009. IEEE International Symposium on; 06/2009
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    ABSTRACT: This paper presents a new procedure to track the disturbance source location of voltage sags and shunt capacitor switching transients in a power system based on branch current measurements. In the proposed method, the power-quality metering locations are first determined by the sensitivity of the system fault-current level to the fault voltage. Then, a current deviation index for representing the change of each measured branch current rms magnitudes before and after the disturbance is calculated to track the disturbance source location within an area confined by the directions of the top-priority branches. The IEEE 30-bus benchmark system and an actual transmission system with recorded power-quality disturbance events are used to illustrate the usefulness of the proposed method. Simulation results obtained by the proposed method are also compared with those obtained by a previously developed approach and by actual recorded data. By observing the results, it shows that the proposed method is efficient and accurate to track the source area of voltage sags or shunt capacitor switching transients.
    IEEE Transactions on Power Delivery 11/2008; · 1.52 Impact Factor

Publication Stats

136 Citations
33.48 Total Impact Points

Institutions

  • 2013
    • National Central University
      • Department of Electrical Engineering
      Taoyuan City, Taiwan, Taiwan
  • 2010
    • Asia University
      臺中市, Taiwan, Taiwan