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 22 for “"current transformer"”.
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Current-Transformer Based Gate-Drive Power Supply With Reinforced Isolation
… design, a low input-output capacitance (CI/O) transformer design, good voltage regulation, as well as good resilience to faults to enable safe and fast operation. In this thesis, a power supply that supplies multiple gate drivers for 10 kV SiC MOSFETs is presented. A transformer design approach …
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Direct Current Transformer (DCX): Converter Integration, Modular Operation, and Efficiency Improvement Through Synchronous Rectification
El Transformador de Corriente Continua (DCX) es un convertidor CC-CC aislado de relación fija, opera sin control en lazo cerrado, generalmente basado en topologías resonantes para maximizar la eficiencia. Está compuesto por un Generador de Tensión Conmutada de Alta Frecuencia, un transformador, un …
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High-frequency Current-transformer Based Auxiliary Power Supply for SiC-based Medium Voltage Converter Systems
… does not satisfy the demands. To improve the current designs, this thesis presents a 1 MHz isolated APS design using gallium nitride (GaN) devices with MV insulation reinforcement. By adopting LCCL-LC resonant topology, the proposed APS is able to supply multiple loads simultaneously and …
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Current transformers transient response modelling using electromagnetic transient program (EMTP)
The subject of this thesis is Current Transformer Transient response study using an electromagnetic Transient program (EMTP). Current transformers are considered eyes for power system protection. Behaviours of protection systems depend largely on information fed to them by instrument transformers. …
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A microprocessor based bus relay
… a new technique to overcome the problem of current transformer saturation. The protection scheme uses a combination of the percentage differential current principle and the phase comparison principle. A sampling rate of 1440 Hz is used. Existing algorithms for a saturation detector are …
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Modeling, Detection, and Localization of High-Impedance Faults In Low-Voltage Distribution Feeders
… to investigate typical patterns in the line's current that allow for the detection of these faults. The occurrence of HIFs is detected with harmonic-current phase analysis and localized with recloser-sectionalizer technology as presented in this work. A sectionalizer algorithm is then presented …
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A method of measuring negative-phase-sequence currents in a three-phase system
A method of measuring the negative-sequence current in an unbalanced three-phase circuit. A four-winding current transformer, in conjunction with a phase shift network and an alternating current ammeter, was used for obtaining a current proportional to, and in phase with, the negative-sequence …
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Electromagnetic energy harvester and self-powered embedded system
… a power line of a load, in the manner of a current transformer. In contrast to the conventional usage of magnetic elements, such as transformers and inductors, the analysis on this "current transformer" reveals a critical result: for any given core for any particular application, power …
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Design of feedforward active ripple filters for power converters
… circuit which cancels or suppresses the ripple current and EMI generated by the power stage of a power converter, thus reducing the passive filtration requirements. This thesis presents the design and evaluation of various current sensing and injection methods for feedforward active filter …
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An improved bus protection technique with dissimilar current transformers
… bus relay includes a new technique to detect current transformer saturation. This saturation detector is the Masters thesis work of Dr. Lifeng Yang, an alumnus of Virginia Tech. A newly developed type of measuring device called a Magneto Optic Current Transducer (MOCT) has been installed on …
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Simulation of power station protection equipment
… to enable the coordination of fuses and overcurrent relays for radial power systems under estimated fault current conditions. The grading curves for these protection devices can be produced on a graphics terminal and a hard copy can be obtained. Additional programs have also been developed …
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Core Material Evaluation for Magnetic Energy Harvester Applications
Current transformer magnetic energy harvesters (CTMEHs) harvest magnetic energy from an AC current-carrying conductor and convert this energy into usable electrical energy for use by various low-power devices, such as sensors and microcontrollers. The amount of power harvested by CTMEHs is …
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Measurement and Modeling for Resource Monitoring
… available at the installation site. The toroidal current transformer based magnetic energy harvester (CTMEH), which leverages the existence of extensive electrical power grid cabling, provides a potential solution. Its usefulness, however, is limited by the need to thread the power conductor …
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Protection system representation in the Electromagnetic Transients Program
… A protection system consists of instrument transformers, relays, and circuit breakers. Models for current transformers and capacitor voltage transformers are developed, validated, and incorporated in EPRI/DCG EMTP Version 2.0. The user can define the values of the current transformer and …
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BEHAVIOR OF BUSBAR DIFFERENTIAL RELAYS WITH AIR-GAP CORE CURRENT TRANSFORMERS
… estimate the magnitude and phase angle of current. Since the level of current is normally too high to permit a direct connection to the power system, a Current Transformer (CT) is used to scale down the current value. A CT should faithfully replicate waveform of the primary current. Power …
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Insights into the radiation Chemistry of FLASH Radiation Therapy
… and benchmarked against a reference alternating-current current transformer (ACCT). Performance metrics included linearity with charge per pulse and total charge, pulse width (0.5–4 µs), mean and instantaneous dose rate, and pulse repetition frequency (5–180 Hz). Alanine dosimetry was also …
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Data-driven Protection of Transformers, Phase Angle Regulators, and Transmission Lines in Interconnected Power Systems
… awareness and data availability.</p><p>Power transformers, Phase Shift Transformers or Phase Angle Regulators, and transmission lines are critical components in power systems, and ensuring their safety is a primary issue. Differential relays are commonly employed to protect transformers, …
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High performance control of VRM circuits
… because of its ability to handle large load current and to achieve fast dynamic transient response under large step-load condition.The first part of this thesis fully investigates this issue for three popular control schemes used currently: Voltage Mode Control (VMC), Average Current Mode …
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Synchronized Phasor Measurement Units Applications in Three-phase Power System
… system. By aligning time stamps of voltage and current phasor measurements, which are consistent with Coordinated Universal Time (UTC), a coherent picture of the power system state can be achieved through either direct measurements or simple linear calculations. With the growing number of PMUs …
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Space charge determination in HVDC power cable and its influence on electric field
… cable. At present, most high voltage direct current (HVDC) installation uses traditional (oil-impregnated paper insulation and oil-filled-types) cables which pose a risk of environmental pollution in case of an accident. <br/><br/>Thus, significant advances and usage of polymeric material, …
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