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249 results for “Voltage”
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Research ArticleOpen accessEvery word in the titleNew Control Technique Applied in Dynamic Voltage Restorer for Voltage Sag MitigationRosli Omar, Nasrudin Abd Rahim, Marizan SulaimanThe Dynamic Voltage Restorer (DVR) was a power electronics device that was able to compensate voltage sags on critical loads dynamically. The DVR consists of VSC, injection transformers, passive filters and energy storage (lead acid battery). By injecting an appropriate voltage, the DVR restores a voltage waveform and ensures constant load voltage. There were so many types of the control … …American Journal of Engineering and Applied Sciences, Vol. 3, Issue 1 · 31 Mar 2010 · 8,136 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleVoltage Sag Effects on the Process Continuity of a Refinery with Induction Motors LoadsTarek I. ElShennawy, Mahmoud A. El-Gammal, Amr Y. Abou-GhazalaProblem statement: Process continuity of industrial plants (like a refinery) is subjected to several shutdowns due to voltage sags causing large induction motors to trip, either by undervoltage or by overcurrent relays, sometimes by the mechanical protection. These unplanned shutdowns cost the plant tens of thousands of dollars per shutdown in addition to material damage costs, restart charges and any … …American Journal of Applied Sciences, Vol. 6, Issue 8 · 31 Aug 2009 · 7,120 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleApplication of Direct Current and Temperature Stresses of Low-Voltage ZnO Based Varistor CeramicsM. G.M. Sabri, B. Z. Azmi, Zahid Rizwan et al.Problem statement: The stresses to humidity, DC and AC bias, multiple impulse voltages and high temperatures are known to affect the varistor performance and it is also interesting to know the effect of both DC bias and temperature stresses at the same time. Approach: Here, the simultaneous DC and temperature stresses degradation was investigated to see the changes of nonlinear … …American Journal of Applied Sciences, Vol. 6, Issue 8 · 31 Aug 2009 · 8,379 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleElectric Power System Under-Voltage Load Shedding Protection Can Become a TrapLuiz Augusto Pereira Fernandes, Alexandre Rocco, Heraldo Silveira Barbuy, Geraldo Caixeta GuimarãesProblem statement: Under-Voltage Load Shedding (UVLS) protection of Electric Power Systems (EPS) is frequently used against Voltage Collapse (VC), however when there is automatic bus voltage regulation with excessive capacitive compensation, the UVLS scheme may not trip. In this case, load shedding must be based in a Voltage Collapse Proximity Indicator (VCPI). Many UVLS procedures may not be appropriate today. … …American Journal of Applied Sciences, Vol. 6, Issue 8 · 31 Aug 2009 · 7,203 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleDegradation of High Voltage Polymeric Insulators in Arid Desert's Simulated Environmental ConditionsYasin KhanProblem statement: High Voltage (HV) polymeric insulators are replacing ceramic insulator commonly used for HV outdoor networks due to their ease of handling, reliability and cost. However, their long term performance and reliability are major concerns to power utilities. Approach: To investigate their performance in arid desert's conditions, two types of HV composite insulators were aged as per International Electrochemical … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 2 · 30 Jun 2009 · 8,098 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA Fast Series Active Filter using Sliding Mode Control to Correct and Regulate Unbalance Voltage in Three-Phase SystemTheerayuth ChatchanayuenyongProblem statement: A Sliding Mode Controller (SMC) with fast reference voltage generation to correct and regulate unbalance voltage in three-phase system was proposed. Approach: The compensation algorithm was not based on three-symmetrical component decomposition so the controller can yield a fast response that was essential in such a critical real time control work. The reference voltages were fed to the … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 2 · 30 Jun 2009 · 7,221 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA GA Based Transmission Network Expansion Planning Considering Voltage Level, Network Losses and Number of Bundle LinesS. Jalilzadeh, H. Shayeghi, M. Mahdavi, H. HadadianTransmission Network Expansion Planning (TNEP) was studied considering voltage level, network losses and number of bundle lines using decimal codification based genetic algorithm (DCGA). TNEP determines the characteristic and performance of the future electric power network and directly influences the operation of power system. Up till now, various methods have been presented for the solution of the Static Transmission Network … …American Journal of Applied Sciences, Vol. 6, Issue 5 · 31 May 2009 · 7,585 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleVoltage Collapse Risk Associated to Under-Voltage Capacitive Compensation in Electric Power System OperationHeraldo Silveira Barbuy, Alexandre Rocco, Luiz Augusto Pereira Fernandes, Geraldo Caixeta GuimarãesProblem statement: In the operation of an Electric Power System (EPS), it has been usual to provide reactive power injection to avoid an under-voltage bus condition. In some situations an adequate voltage profile will not be a guarantee against Voltage Collapses (VCs) that may cause blackouts as seen in many occurrences around the world. The repeatedly injection of reactive power … …American Journal of Applied Sciences, Vol. 6, Issue 4 · 30 Apr 2009 · 7,253 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA Novel Method for Optimal Location and Expansion of Subtransmission Substations Considering Existing Medium-Voltage Distribution FeedersM. Farrokhifar, M. Bana Sharifian, R. EsmaeilzadehThis research presents an accurate comprehensive cost function for the problem of optimal location of subtransmission substations. Technical constraints and economical parameters are investigated in the modeling. Genetic algorithm is used to optimize the cost function. Coding of decision variables is done in a way that finding the correct solutions is achieved faster. For the first time in this study, … …American Journal of Applied Sciences, Vol. 6, Issue 3 · 31 Mar 2009 · 7,788 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleVoltage-Gated Channels as Causative Agents for EpilepsiesMutasem Abuhamed, Xiao Bo, Kun Xia et al.Problem statement: Epilepsy is a common neurological disorder that afflicts 1-2% of the general population worldwide. It encompasses a variety of disorders with seizures. Approach: Idiopathic epilepsies were defined as a heterogeneous group of seizure disorders that show no underlying cause .Voltage-gated ion channels defect were recognized etiology of epilepsy in the central nervous system. The aim of this article … …American Journal of Immunology, Vol. 4, Issue 4 · 31 Dec 2008 · 6,959 accessesView PDFCite