The Experts below are selected from a list of 6537 Experts worldwide ranked by ideXlab platform
Math Bollen - One of the best experts on this subject based on the ideXlab platform.
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A LSTM-based deep learning method with application to Voltage Dip classification
2018 18th International Conference on Harmonics and Quality of Power (ICHQP), 2018Co-Authors: Ebrahim Balouji, Azam Bagheri, Math Bollen, Irene Yu-hua Gu, Mahmood NazariAbstract:In this paper, a deep learning (DL)-based method for automatic feature extraction and classification of Voltage Dips is proposed. The method consists of a dedicated architecture of Long Short-Term Memory (LSTM), which is a special type of Recurrent Neural Networks (RNNs). A total of 5982 three-phase one-cycle Voltage Dip RMS sequences, measured from several countries, has been used in our experiments. Our results have shown that the proposed method is able to classify the Voltage Dips from learned features in LSTM, with 93.40% classification accuracy on the test data set. The developed architecture is shown to be novel for feature learning and classification of Voltage Dips. Different from the conventional machine learning methods, the proposed method is able to learn Dip features without requiring transition-event segmentation, selecting thresholds, and using expert rules or human expert knowledge, when a large amount of measurement data is available. This opens a new possibility of exploiting deep learning technology for power quality data analytics and classification.
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developments in Voltage Dip research and its applications 2005 2015
International Conference on Harmonics and Quality of Power, 2016Co-Authors: Azam Bagheri, Math BollenAbstract:This paper presents a review of literature on Voltage Dips, from several points of view, throughout the last decade. It also summarizes the results related to Voltage Dip mitigation in both AC and DC power systems whereas it shows the remaining challenges that requires further research on Voltage Dips.
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Developments in Voltage Dip research and its applications, 2005–2015
2016 17th International Conference on Harmonics and Quality of Power (ICHQP), 2016Co-Authors: Azam Bagheri, Math BollenAbstract:This paper presents a review of literature on Voltage Dips, from several points of view, throughout the last decade. It also summarizes the results related to Voltage Dip mitigation in both AC and DC power systems whereas it shows the remaining challenges that requires further research on Voltage Dips.
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Voltage Dip immunity of equipment and installations messages to stakeholders
International Conference on Harmonics and Quality of Power, 2012Co-Authors: Math Bollen, Sasa Z. Djokic, Kurt Stockman, Robert Neumann, Gaetan Ethier, J R Gordon, Koen Van Reussel, Snezana CundevaAbstract:This paper presents the messages to the stakeholders on Voltage-Dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-setting-organizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers.
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Voltage Dip immunity aspects of power electronics equipment recommendations from cigre cired uie jwg c4 110
International Power Electronics and Motion Control Conference, 2010Co-Authors: Math Bollen, Snezana Cundeva, Sasa Z. Djokic, Kurt Stockman, Jovica V. Milanovic, Robert Neumann, J R Gordon, Gaetan EthierAbstract:This paper presents some of the results from an international working group on Voltage-Dip immunity. The working group has made a number of recommendations to reduce the adverse impact of Voltage Dips. Specific recommendations to researchers and manufacturers of power-electronic equipment are: considering all Voltage Dip characteristics early in the design of equipment; characterize performance of equipment by means of Voltage-Dip immunity curves; and made equipment with different immunity available.
Gaetan Ethier - One of the best experts on this subject based on the ideXlab platform.
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Voltage Dip immunity of equipment and installations messages to stakeholders
International Conference on Harmonics and Quality of Power, 2012Co-Authors: Math Bollen, Sasa Z. Djokic, Kurt Stockman, Robert Neumann, Gaetan Ethier, J R Gordon, Koen Van Reussel, Snezana CundevaAbstract:This paper presents the messages to the stakeholders on Voltage-Dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-setting-organizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers.
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Voltage Dip immunity aspects of power-electronics equipment — Recommendations from CIGRE/CIRED/UIE JWG C4.110
11th International Conference on Electrical Power Quality and Utilisation, 2011Co-Authors: Math H. J. Bollen, Snezana Cundeva, José-maria Romero Gordon, Sasa Z. Djokic, Kurt Stockman, Jovica V. Milanovic, Robert Neumann, Gaetan EthierAbstract:This paper presents some of the results from an international working group on Voltage-Dip immunity. The working group has made a number of recommendations to reduce the adverse impact of Voltage Dips. Specific recommendations to researchers and manufacturers of power-electronic equipment are: considering all Voltage Dip characteristics early in the design of equipment; characterize performance of equipment by means of Voltage-Dip immunity curves; and made equipment with different immunity available.
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Voltage Dip immunity aspects of power electronics equipment recommendations from cigre cired uie jwg c4 110
International Power Electronics and Motion Control Conference, 2010Co-Authors: Math Bollen, Snezana Cundeva, Sasa Z. Djokic, Kurt Stockman, Jovica V. Milanovic, Robert Neumann, J R Gordon, Gaetan EthierAbstract:This paper presents some of the results from an international working group on Voltage-Dip immunity. The working group has made a number of recommendations to reduce the adverse impact of Voltage Dips. Specific recommendations to researchers and manufacturers of power-electronic equipment are: considering all Voltage Dip characteristics early in the design of equipment; characterize performance of equipment by means of Voltage-Dip immunity curves; and made equipment with different immunity available.
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Voltage Dip immunity of equipment and installations status and need for further work
China International Conference on Electricity Distribution, 2010Co-Authors: Math Bollen, Sasa Z. Djokic, Kurt Stockman, Jovica V. Milanovic, Robert Neumann, Gaetan Ethier, J R Gordon, Francisc ZavodaAbstract:This paper presents the results from the work of WG C4.110, a joint working group by CIGRE, CIRED and UIE. Its mandate period stretched from early 2006 through early 2009. The group has addressed several aspects of the immunity of, especially, industrial equipment against Voltage Dips. Compared to the work earlier groups, the equipment performance is not seen as a final aim, but as a step towards the ultimate aim: allowing the process to ride through the Voltage Dip. Some of the contributions and conclusions from the WG C4.110 are discussed in this paper, ✓ Description of Voltage Dips, ✓ Equipment and process immunity, ✓ Testing and characterization, ✓ Economics, ✓ Immunity classes and application, ✓ Further work.
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Voltage Dip immunity statistics and need for further work
Renewable energy & power quality journal, 2010Co-Authors: Math Bollen, Sasa Z. Djokic, Kurt Stockman, Jovica V. Milanovic, Robert Neumann, J R Gordon, Gaetan EthierAbstract:This paper presents the main results from CIGRE/CIRED/UIE working group JWG C4.110 and an overview of the need for further work identified by this working group. The paper goes into more details of the volt age-Dip statistics collected by the working group and on me thods to present the results from Voltage-Dip surveys.
Massimo Bongiorno - One of the best experts on this subject based on the ideXlab platform.
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A Generic DFIG Model for Voltage Dip Ride-Through Analysis
IEEE Transactions on Energy Conversion, 2013Co-Authors: Massimo Bongiorno, Torbjörn ThiringerAbstract:The modeling of a Doubly fed induction generator (DFIG) system for a wind turbine application is investigated in this paper. The electrical generating system is equipped with a dc crowbar system for fault ride through ability. After setting up the basic machine, converter, and grid-filter equations, the various controllers are derived and the selection of the regulator parameters is discussed. To validate the derived model, the investigated DFIG system is simulated using PSCAD/EMTDC and its dynamic response to Voltage Dips is compared to the Dip behavior of an existing 2-MW wind turbine. It will be shown that the developed generic model exhibits the same dynamic performance as the actual wind turbine during and directly after a Voltage Dip recorded at the wind-turbine site, even in case of a severe event where the Voltage at the connection point drops to 0% during the Voltage Dip.
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Voltage Dip Mitigation Using Shunt-Connected Voltage Source Converter
IEEE Transactions on Power Electronics, 2007Co-Authors: Massimo Bongiorno, Jan SvenssonAbstract:In this paper, a Voltage source converter (VSC) connected in shunt with the grid to mitigate Voltage Dips for sensitive processes is presented. The VSC maintains the magnitude of the grid Voltage at the connection point constant by injecting reactive power to compensate for the Voltage Dip. This is achieved by using a cascade controller, constituted by an inner vector current-controller (VCC) and an outer Voltage controller, which calculates the current references for the VCC. The paper shows that using an inductor/capacitor/inductor (LCL)-filter instead of the simpler L-filter in between the VSC and the grid yields high performance and robust controller. Furthermore, in order to compensate for unbalanced Dips, both positive- and negative-sequence components of the grid Voltage must be controlled separately. This is done by using two independent controllers for the two sequences, with the same cascaded structure described above. Simulation results under balanced and unbalanced Dips are presented to show the performance. Also, stability analyses are done to determine the robustness of the system against grid parameter variation.
M.h.j. Bollen - One of the best experts on this subject based on the ideXlab platform.
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Comparing Voltage Dip survey results
2002 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.02CH37309), 2002Co-Authors: M.h.j. BollenAbstract:Different Voltage-Dip surveys often present the results in different ways. This complicates the comparison of the results. In this paper a method is presented for translating the results from one way of presenting to another way of presenting. The Voltage-Dip contour map is used thereby as an intermediate step. As an example the results of the EPRI-DPQ survey are presented in UNIPEDE format.
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On Voltage Dip propagation
2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262), 2001Co-Authors: M.h.j. BollenAbstract:Voltage Dips due to faults at high-Voltage level, change magnitude when they propagate to lower Voltage levels. Measurements are shown to quantify this phenomenon. The measurements presented show that the remaining rms Voltage increases when moving towards the load. The severe change in load current due to the drop in Voltage, mitigates the Voltage Dip. For unbalanced Dips it is shown that the positive-sequence Voltage increases and the negative-sequence Voltage decreases towards the load. More measurements and simulation studies are needed to confirm. and explain this behaviour. A Voltage drop index is introduced as a measure of the effect of the load current on the rms Voltage during a Voltage Dip.
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Voltage Dip detection and power system transients
2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262), 2001Co-Authors: E. Styvaktakis, I.y.h. Gu, M.h.j. BollenAbstract:Recently developed power quality mitigation equipment, like the static transfer switch, needs methods for fast and reliable detection of Voltage Dips. Such a detection scheme must be able to detect a Voltage Dip as fast as possible and be immune to other types of disturbances. In this paper, the authors address the problem of Voltage Dip detection regarding Kalman filtering, the characteristics of fault-induced Voltage Dips and other power system disturbances. They investigate how the Voltage Dip characteristics influence the speed of detection and show that disturbances other than fault-induced Dips could trigger a detection scheme. Special attention is given to trans former-related events. Their characteristics are presented using measurements. Kalman filtering modelling issues are discussed. Statistics on the characteristics of fault-induced Dips and transformer events are presented from medium Voltage networks.
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Expert system for Voltage Dip classification and analysis
2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262), 2001Co-Authors: E. Styvaktakis, M.h.j. Bollen, I.y.h. GuAbstract:The increasing amount of data obtained by power quality monitors and the need for better understanding of power system disturbances require new analysis tools. This paper presents an expert system that is able to classify different types of Voltage Dips according to the underlying causes (i.e. events) and offer useful information in terms of power quality. The expert system uses the Voltage waveforms and distinguishes the different types of Voltage Dips (fault-induced, transformer saturation, induction motor starting), explains the changes in the Voltage Dip magnitude (change in the system, change in the fault type, transformer saturation, motor load influence) and separates interruptions into non-fault and fault-induced. A method is proposed for event-based classification, where a segmentation algorithm is first applied to divide waveforms into several possible events. Kalman filtering is employed to model the waveforms and the residuals of the model are used for segmentation. The expert system is tested using real measurements and the results show that the system enables fast and accurate analysis of data from power quality monitors.
S. Chowdhury - One of the best experts on this subject based on the ideXlab platform.
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a review of Voltage Dip mitigation techniques with distributed generation in electricity networks
Electric Power Systems Research, 2013Co-Authors: O. Ipinnimo, S.p. Chowdhury, S. Chowdhury, J. MitraAbstract:Abstract The advent of power quality sensitive equipment has made the provision of good power quality a real challenge across the globe. With the increasing usage of sophisticated sensitive electronic equipment in industrial, residential and commercial sectors, it is important to protect them from any power quality disturbance in order to avoid equipment damage and malfunction leading to financial loss for the customer. Voltage quality disturbances such as Voltage Dips pose a serious concern as a power quality problem, since due to their stochastic nature they cannot readily be eliminated from regular utility systems. However, they can be mitigated. High degree of penetration of distributed generation in power networks is useful in delivering different benefits to the utility in the form of ancillary services one of which is Voltage Dip mitigation in case of system contingencies. This paper presents a comprehensive review and comparison of various distributed generation schemes used by utilities for mitigation of Voltage Dips in power networks.
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Voltage Dip analysis of electricity networks on wind energy integration
2013 48th International Universities' Power Engineering Conference (UPEC), 2013Co-Authors: P. Sekhoto, O. Ipinnimo, S. ChowdhuryAbstract:The paper analyses the nature of Voltage Dip in electrical networks integrated with wind energy conversion systems (WECSs) with three different types of generators, viz., permanent magnet synchronous generator (PMSG), doubly-fed induction generator (DFIG) and the fixed speed induction generator (FSIG). The test network along with the wind generators and loads is modeled in DIGSILENT Power Factory. The Voltage Dip is generated by applying a three-phase short-circuit fault to one of the transmission lines in the test network. Impact of wind integration is analyzed and compared for different wind generators, different loadings on the network and different utility grid strengths. The results indicate that out of the three types of wind generators, FSIG is the most unfavorable choice and there are trade-offs between the other two types (PMSG and DFIG).
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Effects of renewable distributed generation (RDG) on Voltage Dip mitigation in microgrids
11th IET International Conference on Developments in Power Systems Protection (DPSP 2012), 2012Co-Authors: O. Ipinnimo, S. Chowdhury, S.p. ChowdhuryAbstract:Many countries are accepting the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) in other to reduce the emission of carbon dioxide and other greenhouse gases. Renewable distributed generation (RDG) has become one of the most effective ways to reach this goal. It has been recognized as an alternative way of generating clean energy around the globe today. There has been an increase in the number of integrated RDG to the grid and also within the microgrids in other to support the power needed by the load during crisis. Current literature highlights Voltage Dips to be a serious problem, which has serious cost implication whenever they occur. One of the corrective methods has been mitigation through renewable distribution generation. This paper demonstrates how renewable distributed generation can be used to mitigate Voltage Dip as a result of faults from both the external grid and within the microgrid.
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Intelligent Voltage Dip detection in power networks with distributed generation (DG)
2012 North American Power Symposium (NAPS), 2012Co-Authors: O. Ipinnimo, S.p. Chowdhury, S. Chowdhury, J. MitraAbstract:Power and energy industry infrastructure dictates the economic growth in any country. The increased use of sophisticated sensitive ICT and semiconductor devices at homes and offices has also led to monitoring of Voltage profile and has increased the challenges for utility and industry to focus on power quality related to Voltage Dips and swells. Industries where a delicate industrial processes demand a high quality Voltage supply, such as textile, process industry or refinery can be particularly susceptible to problems with Voltage Dip because the systems are interconnected and a trip of any component in the process can cause the whole plant to shut down. The early detection and identification of Voltage Dip may help to improve classification and mitigation of Voltage Dip process, leading to a secure operation and reliable power system networks. In this context, this paper presents a novel technique for Voltage Dip detection in power networks with Distributed Generation (DG) using a simple feed forward Artificial Neural Network (ANN) with sigmoid hidden neuron. Voltage Dip is generated through simulation in DIgSILENT Power Factory 14.0 software and the tests are carried out on IEEE 9-bus test system. The model is trained, tested and validated in Matlab environment using neural network Toolbox.
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Impact of transmission faults on the Voltage Dip performance of a weak upington distribution network with a CSP plant connected
2012 IEEE International Conference on Power System Technology (POWERCON), 2012Co-Authors: R. Xezile, S. Chowdhury, N. Mbuli, J.h.c. Pretorius, S.p. ChowdhuryAbstract:The Upington distribution network is remotely located from the main transmission system. It is characterized by long lines supplying relatively small amounts of loads. The fault levels at various points in this network can be characterized as very low. These two aspects can lead to this network being characterized as very weak. As a result, faults taking place at various locations in the system tend to cause severe Voltage Dips. A concentrating solar power plant (CSP) is being planned for commissioning in the area. The presence of the CSP plant will greatly change the fault levels, and network strength, at various locations in the vicinity of the CSP plant. In this paper, a study is conducted to assess the severity of a Voltage Dip at a particular power station before and after commissioning of a CSP plant. A 3-phase transmission fault recorded historically is simulated. It is shown that the presence of the CSP plant has substantially beneficial effect on the Voltage Dip performance of the system.
