Condition monitoring of transformer: Electrical Seminar Topic

Transformers are a large part of the component structure of the electricity system. Knowing the condition is essential to meeting the goals of maximizing return on investment and lowering total cost associated with transformer operation.

In order to reconcile both decreasing maintenance spending and reliable service, condition based maintenance (CBM) is often proposed. The successful application of CBM lies in obtaining information transformers, so that, on the one hand, a critical condition will be noted early enough to take measures and on the other hand, so that only minimal maintenance is being applied to transformers still in good condition.

The paper covers the following areas.
• General aspects of aging in transformers.
• An overview of condition monitoring methodology with partial discharge patterns in focus.
• Partial discharge measurement and diagnostics on power transformer using a multi channel digital PD detector.

Brush-less servomotor

A brush-less servomotor has been developed by using interdisciplinary mechatronics engineering. A mechanical switching device (commutator) is replaced by electronic circuits and controllers resulting in maintenance free and high performance servo drive.
The brush-less servomotor is an ac motor, in all respects and is in fact called the ac servomotor. Combined with a dedicated control device, the performance of the brush-less servomotor is found to be equal to the performance of the high performance dc servo motor.
The rotational speed of dc servomotor is generally varied by changing the voltage applied to the armature. As the armature voltage is nearly proportional to the rotational speed, the speed can be slowed down as much as is required by lowering the applied voltage. On the other hand the rotational speed of the ac motor is generally varied by changing the frequency. However the frequency has its limits of variation. A wide range of speed variation, which is a feature of servomotors, cannot be obtained by using only a simple inverter.
In dc motor when the current flows in the electrical conductor, after passing through the brushes and the commutator in the magnetic field generated by permanent magnets N and S, torque is generated. For getting a stable torque proportional to current, the line of magnetic force should intersect the c of current at right angles in a dc motor. This is enabled by the use of rectifiers (a commutator and brushes).
In ac motors slip ring is used instead of a commutator and a power source of alternating current makes the rotor rotate continuously at the rotational speed corresponding to the applied frequency. But the brushes of the ac motors can be eliminated by changing the revolving armature structure in to revolving field type.

Axial-field electrical machines abstract

Axial-field electrical machines offer an alternative to the conventional machines. In the axial-field machine, the air gap flux is axial in direction and the active current carrying conductors are radially positioned. This paper presents the design characteristics, special features, manufacturing aspects and potential applications for axial-field electrical machines. The experimental from several prototypes, including d.c. machines, synchronous machines and single-phase machines are given. The special features of the axial-field machine, such as its planar and adjustable air gap, flat shape, ease of diversification, etc., enable axial-fled machines to have distinct advantages over conventional machines in certain applications, especially in special purpose applications.

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AUTOMATIC SOLAR TRACKER .Electrical seminar topics

A new control scheme for a single – phase diode clamped rectifier is proposed to achieve a unity power factor, balanced neutral point voltage and constant DC-bus voltage. Four power switches are used in the rectifier to generate a three-level PWM wave form on the rectifier terminal voltage.The line current command is derived from a DC-link voltage regulator and an output power estimator. The hysteresis current Controller is used to track the line current command. To balance the neutral-point voltage, a capacitor voltage compensator is employed. The main advantages of using a three-level instead of a two-level PWM scheme are that the blocking voltage of each power switch is clamped to half the DC-bus voltage (if the off –state resistance of  power switches is equal),and the voltage  harmonic on the AC  side of rectifier is reduced.

AUTOMATED DISTRIBUTION SYSTEM With Full seminar Report

Distribution systems are usually composed of radial feeders. Each feeder is divided into load sections with sectionalizing switches and is usually connected to other feeders via normally open tie switches.

 When a fault occurs in the distribution system, it is firstly detected by protection relays, then a circuit breaker is opened and de-energizes the feeder where the fault exists. By operating sectionalizing switches, the faulted section is isolated and the un-faulted sections disconnected are re-energized after reclosing the circuit breaker.

As automation is introduced into the distribution systems, the above switching operations can become automated. Recent advances in digital technology have made possible the development of Distribution Automation System (DAS). The DAS offers many new opportunities for improved system operation. It provides an integrated system approach to monitoring, protection, and control.

 Distribution automation includes wide spread functions, among which feeder automation is an important aspect. By controlling line switches installed on the feeder, feeder automation functions can be accomplished by identifying and isolating permanent feeder faults and restoring service to the un-faulted feeder sections sequentially and automatically, and thus reduce significantly customer outage time. The distribution automation discussed in this paper is restricted to fault isolation, reconfiguration, and service restoration switching operations.
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Numerical modeling of active plasmonic nanoparticles

Enhanced scattering and light localization beyond the diffraction limit due to plasmon resonance in metallic nanoparticles is a well known phenomena and has been applied for a wide range of useful applications including nanoparticle waveguides, bio-sensors and several others. Based on the classical Mie theory it can be shown that by enclosing an active media in a nanoparticle, metallic losses can be overcome and a nanoparticle can be made to radiate by itself. This result can extend the use of plasmonic nanoparticles far beyond the current limitations and pave the way for lossless plasmonic waveguides, energy storage devices and nanolasers. This research aims to investigate, in theory and using numerical techniques, how these applications can be realized.

Ph.D. Seminar topic Analytical and Numerical Modeling of Subwavelength Plasmonic-waveguide Components for Nanophotonic Applications

Recently, in optics there has been a surge of interest in miniaturized metallic structures
that allow sub-wavelength control of electromagnetic energy in the infrared and visible
bands of the spectrum. This results an emerging field of science known as plasmonics,
which has plethora of applications such as nanoscale optical interconnects,
chemical/bio-sensors, high-resolution microscopy, etc.
This research aims to investigate various plasmonic waveguide-based optical
components in terms of equivalent transmission-line networks. This representation
allows one to use classical network analysis tools in microwave engineering to obtain
analytical expressions that describe the transmission response of useful devices in
nanophotonics. The derived formulae provide rapid design optimization paths unlike the
computationally expensive and time consuming numerical simulations.