Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 43 for “"Power transformers"”.
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First principles design of coreless power transformers
… designing novel 4-coil high frequency coreless power transformers from first principles via lumped equivalent circuit models. The procedure is applied to construct a design for 100W transformer with an S21 parameter value of .96. Using MATLAB and LTspice, simulation tools have been developed to …
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Impact of Geomagnetically Induced Currents on Power Transformers
… of Geomagnetically Induced Current (GIC) on power transformers in electrical power systems. A simulator to calculate the flows of GIC in an electrical power network, based on an assumed or measured induced geoelectric potential is proposed. This simulator includes all needed mapping …
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Effects of geomagnetically induced currents on power transformers and reactors
Bibliography: leaves 106-109.
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Condition assessment using dissolved gas analysis on transmission power transformers
In transmission networks, power transformers and reactors play a major role in the supply of power in the country. Power transformers and reactors are identified as most critical assets and have a significant impact on power network reliability. It is thus important to know the effective condition …
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A New Approach to Assessment and Utilisation of Distribution Power Transformers
Electrical power systems utilise several voltage levels using power transformers to transfer voltages and connect parts of the power system with different voltage levels. One of these voltage transformations is being performed in the key component of the electrical power system: the distribution …
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Saturation Effects in 3p3L Power Transformers due to Geomagnetically Induced Currents
… dc excitation can impact the normal operation of power transformers in transmission networks. The impact is caused by the dc current introduced into the windings of a transformer energised with ac, which leads to a simultaneous dc magnetomotive force (mmf) resulting in part-cycle saturation of the …
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Automated diagnosis of large power transformers using adaptive model-based monitoring
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.
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A neural fuzzy approach to modeling the thermal behavior of power transformers
… and 27 MVA Forced Air (FA)-cooled class of power transformers. The models were derived from real data of temperature measurements obtained from two industrial power installations. A comparison of the proposed techniques is presented for predicting top and bottom-oil temperatures based on the …
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Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization
Energization of large power transformers are subject to many transients that may complicate the successful completion of this process and ultimately reduce the expected life of these critical components. The first-time energization (commissioning), subsequent energizations (operational), methods of …
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A class of high-efficiency air-core power transformers with flux-guiding resonators
Developments in high frequency power semiconductors have enabled the miniaturization of power system components, leading to the reduction of heavy, lossy magnetic steel cores as a media for electromagnetic energy transfer. A final push towards fully “air-core” power devices is underway and a new …
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Modeling, analysis, and design of high-frequency high-density low-profile power transformers
… modeling and analysis techniques for low-profile transformers in power electronics. Based on the modeling and analysis, the design methodologies and design tools are provided. High frequency low-profile transformer 1-D winding loss, core loss and temperature rise models are derived in terms of the …
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The theory and design of switched-mode power transformers for minimum conductor loss
… general analysis of the electromagnetic fields, power dissipation, and energy storage within transformer windings is presented. Emphasis is placed on applications in switched-mode power conversion. One-dimensional radial variation of the field quantities is assumed. The first phase of the …
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Three-phase five limb transformer responses to geomagnetically induced currents
… Geomagnetically induced currents enter into the power system through grounded neutrals of power transformers. The potential effects of GIC on transformers are asymmetrical saturation, increased harmonics, noise, magnetization current, hot spot temperature rise and reactive power consumption. …
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An optic fiber sensor for partial discharge acoustic detection
… (PD) is a very common problem in operating power transformers and is one of the factors that could lead to failure of power transformers, leading to power outage and expensive repairs. The acoustic wave induced by PD can be measured and used for monitoring, diagnosing, and locating potential …
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Study of Power Transformer Abnormalities and IT Applications in Power Systems
With deregulation, diagnosis and maintenance of power equipment, especially power transformers, become increasingly important to keep power systems in reliable operation. This dissertation systematically studied two kinds of transformer failure and abnormality cases, and then developed a new …
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Detection and Position Location of Partial Discharges in Transformers Using Fiber Optic Sensors
Power transformers are one of the most important components in the electrical energy network. Extending transformer life is very economically valuable due to power outage. Therefore the development of instruments to monitor the transformer condition is of great interest. Detection of partial …
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Data driven artificial intelligence techniques in renewable energy system
Today's power grid is composed of different kinds of distributed energy resources (DER) such as solar panels, wind farms, batteries and power transformers. DERs often come with data interfaces and IoT sensors which generate large amounts of data. Besides monitoring device status, those data can be …
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Development of Novel Optical Fiber Interferometric Sensors with High Sensitivity for Acoustic Emission Detection
… on-line detection of acoustic emissions in power transformers, this dissertation presents the comprehensive research work on the theory, modeling, design, instrumentation, noise analysis, and performance evaluation of a diaphragm-based optical fiber acoustic (DOFIA) sensor system. The …
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The response of transformers to geomagnetically induced- like currents
… protocol for characterizing and testing transformers with GIC-like currents based on their magnetization curve characteristics. The differences between reactive and non-active power in the context of transformers and GICs are investigated thoroughly and their impact on power networks are …
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Optimal Mitigation of Geomagnetically Induced Current Effects in Power Systems Considering Transformer Thermal Limits
… (GIC) which have adverse effects on the national power grid and potentially damage transformers on the grid. GIC flowing along transmission lines and through the transformers in power systems can be attributed to problems ranging from overheating of power transformers, harmonic generation, and …
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