Investigation of effective automatic recognition systems of power-quality events

Copyright © 2007 IEEE. All Rights Reserved.There is a need to analyze power-quality (PQ) signals and to extract their distinctive features to take preventative actions in power systems. This paper offers an effective solution to automatically classify PQ signals using Hilbert and Clarke Transforms as new feature extraction techniques. Both techniques accommodate Nearest Neighbor Technique for automatic recognition of PQ events. The Hilbert transform is introduced as single-phase monitoring technique, while with the Clarke Transformation all the three-phases can be monitored simultaneously. The performance of each technique is compared with the most recent techniques (S-Transform and Wavelet Transform) using an extensive number of simulated PQ events that are divided into nine classes. In addition, the paper investigates the optimum selection of number of neighbors to minimize the classification errors in Nearest Neighbor Technique.Gargoom, A.M.; Ertugrul, N.; Soong, W.L

Automatic classification and characterization of power quality events

Copyright © 2008 IEEEThis paper presents a new technique for automatic monitoring of power quality events, which is based on the multiresolution S-transform and Parseval's theorem. In the proposed technique, the S-transform is used to produce instantaneous frequency vectors of the signals, and then the energies of these vectors, based on the Parseval's theorem, are utilized for automatically monitoring and classification of power quality events. The advantage of the proposed algorithm is its ability to distinguish different power quality classes easily. In addition, the magnitude, duration, and frequency content of the disturbances can be accurately identified in order to characterize the disturbances. The paper provides the theoretical background of the technique and presents a wide range of analyses to demonstrate its effectiveness.Ameen M. Gargoom, Nesimi Ertugrul and Wen. L. Soon

Voltage stability of power systems with renewable-energy inverter-based generators: A review

© 2021 by the authors. The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids

Voltage Stability of Power Systems with Renewable-Energy Inverter-Based Generators: A Review

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids

Digital signal processing techniques for improving the automatic classification of power quality events.

The work presented in this thesis investigates the application of digital signal processing techniques in the power quality automatic classification field, and thus, proposes an optimized automatic monitoring system with an improved accuracy. The proposed monitoring system involves three main sections: detection of the power quality events, extraction of the distinctive features that characterise each event, and automatic classification of the similar events under pre-defined categories. The thesis proposes new power quality processing techniques for detection and feature extraction sections, including the Hilbert and Clarke transforms. The former proposed technique was used for analysing single phase signals, while the later technique was proposed for the simultaneous analysis of three signals.Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 200

A comparative study on effective signal processing tools for optimum feature selection in automatic power quality events clustering

© Copyright 2005 IEEEThe paper presents a comparative study to investigate the optimum feature selection using three signal processing techniques for automatic clustering of power quality events. The techniques include the wavelet transform, the S transform, and the newly introduced forward Clarke transform. The last method has the advantage for monitoring all three phases of a three-phase signal simultaneously. The paper provides unique features for each transformation, and then offers a comparative study that is based on the abilities of selected pairs of features to distinguish power quality events. In the paper, the performance of each signal processing technique is studied and an optimum combination of the most useful features is identified.Gargoom, A.M. ; Ertugrul, N. ; Soong, W.L

Enhancing the operation of smart inverters with PMU and data concentrators

As inverter-based distributed energy resources (DERs) continue to proliferate in the distribution systems and provide a significant part of the generation, enhancing the visibility of the system for coupling transmission and distribution networks is becoming essential. The paper offers a monitoring and managing approach based on integrating information from synchrophasors and phasor data concentrators (PDCs) to enhance the deployment of the smart inverter, post their dynamic functions and overcome the decoupling between distribution/transmission operations. The proposed approach includes DER monitoring and managing entity (DER-MME) which communicates with PDC units that can manage the smart inverters functions in real-time during normal/abnormal operation based on a proposed fault detection and localization algorithm. Although the approach can be expanded to include several functions, in the paper, the focus was on the momentary cessation function (MC) and how it can be dynamically controlled by the proposed approach to improve the response of smart inverters. The merit of the proposed approach has been illustrated on several transmission and distribution faults that triggered fault-induced delayed voltage recovery (FIDVR) events which are common in distribution networks.© 2022 Elsevier. This manuscript version is made available under the Creative Commons Attribution–NonCommercial–NoDerivatives 4.0 International (CC BY–NC–ND 4.0) license, https://creativecommons.org/licenses/by-nc-nd/4.0/fi=vertaisarvioitu|en=peerReviewed

Comparative study of using dfferent mother wavelets on power quality monitoring

The paper compares the use of various types of mother wavelets on the analysis of power quality signals. The comparison was based on the calculation of the energy of the reconstructed signals from the wavelet coefficients using the wavelet packet transform. The comparison has been done using a number of real power quality signals obtained experimentally.A. M. Gargoom, N. Ertugrul, and W. L. Soon

Power quality indices measurement using the S-transform

Copyright © 2009 Inderscience Enterprises Ltd.The paper presents the S-transform (ST) technique as a new tool for power quality indices measurement. A key feature of the ST is its accurate time-frequency (amplitude and phase) domain. With this feature, it is possible to redefine the calculation of the power quality indices in the ST domain based on the harmonic content of the signals. In addition, using the time information provided by this technique, the definitions of the power quality indices can be extended to be instantaneous. The accuracy of the instantaneous versions of different indices in the ST domain is verified on a number of simulated and real power quality signals.Ameen Gargoom, Nesimi Ertugrul and Wen L. Soon

A digital signal processor controlled smart battery charger for photovoltaic power systems

An off-grid photovoltaic power system requires an energy storage system, especially batteries, for mitigation of variability and intermittency problems, and for assured service reliability and availability. The longevity and reliability of such batteries depend on the effectiveness of the charging system. This paper presents the modelling, simulation and hardware implementation of a four-stage switch-mode charger based on the single-ended primary inductance converter. The digital signal processor based controller implements algorithms for the system\u27s power balance control, maximum power point tracking to improve charging speed and efficiency, four-stage optimal charging, and system\u27s protection. The protection algorithm provides over-charge, overdischarge, over-temperature and short circuit protection capabilities. The proposed system has the following advantages: ability to continuously charge the batteries even at reduced solar irradiation, higher efficiency, and use of adaptive thermally compensated set points for optimum performance. A prototype is built and experimental results are presented to validate the simulation results