Enhanced Detection of Power-Quality Events Using Intra and Interscale Dependencies of Wavelet Coefficients

Dwivedi, U.D.; Singh, Santokh

doi:10.1109/tpwrd.2009.2027482

Cited by 58 publications

(26 citation statements)

References 25 publications

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“…There are two frequency points nearest to f a among all frequency points, one on the left side (denoted as f b1 ) and the other on the right side (denoted as f b2 ). When the modulating signal is in the monotone interval, the frequency point corresponding to the smaller D f value is According to the linearity of discrete wavelet transform [39,40], (10) exits, where DWT( · ) means the discrete wavelet transform operator. Equation (10) shows that the wavelet coefficients of signal c m (t) can be directly calculated from those of signals a m (t) and b m (t), and therefore calculation complexity is reduced.…”

Section: The Proposed Algorithmmentioning

confidence: 99%

Power System Frequency Estimation Algorithm for Electric Energy Metering of Nonlinear Loads

Zhang¹,

Li²

2012

Metrology and Measurement Systems

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In this paper, a discrete wavelet transform (DWT) based approach is proposed for power system frequency estimation. Unlike the existing frequency estimators mainly used for power system monitoring and control, the proposed approach is developed for fundamental frequency estimation in the field of energy metering of nonlinear loads. The characteristics of a nonlinear load is that the power signal is heavily distorted, composed of harmonics, inter-harmonics and corrupted by noise. The main idea is to predetermine a series of frequency points, and the mean value of two frequency points nearest to the power system frequency is accepted as the approximate solution. Firstly the input signal is modulated with a series of modulating signals, whose frequencies are those frequency points. Then the modulated signals are decomposed into individual frequency bands using DWT, and differences between the maximum and minimum wavelet coefficients in the lowest frequency band are calculated. Similarities among power system frequency and those frequency points are judged by the differences. Simulation results have proven high immunity to noise, harmonic and inter-harmonic interferences. The proposed method is applicable for real-time power system frequency estimation for electric energy measurement of nonlinear loads.

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Section: The Proposed Algorithmmentioning

confidence: 99%

Power System Frequency Estimation Algorithm for Electric Energy Metering of Nonlinear Loads

Zhang¹,

Li²

2012

Metrology and Measurement Systems

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“…In over/under voltage and over/under frequency detection, the voltage at point of common coupling (PCC) and the frequency of the inverter at PCC (Node 'a' in Fig.1 where PV is the DG) is continuously monitored [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The inverter should be disconnected to prevent damage to both the inverter and utility, when the voltage or the frequency are out of specified thresholds (207V ≤ V ≤ 253V ) and (48 Hz ≤ f ≤50.5 Hz) specified by the EN 50438 [13].…”

Section: A Under/over Voltage and Under/over Frequency Detectionmentioning

confidence: 99%

“…But if the mismatch is quite small leaving the voltage and frequency within the nominal range would make the islanding detection impossible causing a large non detection zone (NDZ). Also, if the threshold range is set small, nuisance tripping could occur, hence this detection method on its on is not sufficient for anti islanding protection [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: A Under/over Voltage and Under/over Frequency Detectionmentioning

confidence: 99%

A discussion of anti-islanding protection schemes incorporated in a inverter based DG

Hanif¹,

Basu²,

Gaughan³

2011

2011 10th International Conference on Environment and Electrical Engineering

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Abstract-The discussion in this paper is about the local antiislanding protection techniques that are incorporated in a inverter based DG. The most widely used passive and active techniques along with their suitability to reduce the ondetection zone ( DZ) are explained here. The most recent work using wavelet transform which actually reduces the DZ to zero is also introduced in the last section of the paper.

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“…LTR based denoising scheme performs superior to KS test based scheme. Reference (Dwivedi et al, 2010) proposed a low complex technique which exploits the local structure of wavelet coefficients obtained from wavelet multi-resolution decomposition of PQ waveform data as well as high correlation of adjacent wavelet scales for enhancing detection, segmentation and time localization performance of DWT based PQ monitoring systems under practical conditions of harmonics and noise.…”

Section: Effect Of Noise On Pq Event Classifiersmentioning

confidence: 99%

Power quality event classification: an overview and key issues

Saxena¹,

Verma²,

Singh³

2010

Int. J. Eng. Sci. Tech

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Power quality (PQ) issue has attained considerable attention in the last decade due to large penetration of power electronics based loads and/or microprocessor based controlled loads. On one hand these devices introduce power quality problem and on other hand these mal-operate due to the induced power quality problems. PQ disturbances/events cover a broad frequency range with significantly different magnitude variations and can be non-stationary, thus, accurate techniques are required to identify and classify these events/disturbances. This paper presents a comprehensive overview of different techniques used for PQ events' classifications. Various artificial intelligent techniques which are used in PQ event classification are also discussed. Major Key issues and challenges in classifying PQ events are critically examined and outlined.

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Enhanced Detection of Power-Quality Events Using Intra and Interscale Dependencies of Wavelet Coefficients

Cited by 58 publications

References 25 publications

Power System Frequency Estimation Algorithm for Electric Energy Metering of Nonlinear Loads

Power System Frequency Estimation Algorithm for Electric Energy Metering of Nonlinear Loads

A discussion of anti-islanding protection schemes incorporated in a inverter based DG

Power quality event classification: an overview and key issues

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