Electrical and Electronics

A single feed compact rectangular microstrip antenna is presented in this paper. L & H slits are introduced on the edge of the patch to study the effect of the slit on radiation behavior with respect to a conventional microstrip patch. The resonant frequencies are obtained at 2.21, 2.4, 4.36 & 6.41 GHz with corresponding bandwidth 15.18 MHz, 11.85 MHz, 15.14 MHz, 78.91 MHz and return loss of about -23.62, -13.58, -11.46 & -15.65 dB respectively. The antenna has been reduced by 61% when compared to a conventional rectangular microstrip patch. The characteristics of the designed structure are investigated by using MoM based electromagnetic solver, IE3D.

This paper proposes a novel approach for optimal allocation of a distributed generator in a radial distribution feeder for tail end node voltage improvement and loss minimization during peak load. A multi objective optimization method is proposed to determine optimal allocation of a distributed generation (DG) unit in a radial distribution feeder. The DG allocation problem has been formulated as multi objective function which includes two objectives: viz Power Loss Reduction and Tail End Node Voltage Improvement with associated weights. The proposed methodology uses Genetic Algorithm to optimize the multi objective function. This method is tested on standard IEEE 33 bus and 69 bus radial distribution systems using MATLAB 8.0. The results show that the proposed method yields considerable tail end node voltage improvement along with significant reduction in line losses during peak load.

This paper proposes an improved configuration of double flying capacitor multicell (DFCM) converter. The main advantages of the proposed converter, compared to the conventional lDFCM converter, are the doubling of the number of output voltage levels and improvement of the output voltage frequency spectrum. This progress is achieved by adding only two low-power switches and one dc voltage source. However, the number and voltage rating of high-frequency switches and capacitors and the number of high frequency switching’s during a full cycle are kept constant. The doubling of the number of output voltage levels in the proposed converter makes it possible to decrease the number of cells, the number of flying capacitors, as well as their voltage rating and the amount of stored energy in flying capacitors. Moreover, a modulation method based on phase-shifted carrier pulse width modulation is proposed to control the new converter. The doubling of the number of output voltage levels in the proposed converter makes it possible to decrease the number of cells, then number of flying capacitors, as well as their voltage rating and the amount of stored energy in flying capacitors. Moreover, a modulation method based on phase-shifted carrier pulse width modulation is proposed to control the new converter.

Spectral analysis using the Fourier Transform is a powerful technique for stationary time series where the characteristics of the signal do not change with time. For non-stationary time series, the spectral content changes with time and hence time-averaged amplitude spectrum found by using Fourier Transform is inadequate to track the changes in the signal magnitude, frequency or phase. This paper presents a new time-frequency signal analysis method, called Modified S-Transform (MST) with modified Gaussian window, for visual localization, detection of various non-stationary power signals.

Design and simulation of planar inverted folded fractal antennas are designed to operate at wireless communication applications. The proposed models are having size reduction of 15-20% compared to the conventional antennas and operating with stable gain and good bandwidth. First model is resonating at 2.6 GHz and second model is at 2.8 GHz. This paper addresses the development of compact and efficient planar inverted fractal antenna with some methods for improving the bandwidth and reduction in volume. Ansoft HFSS electromagnetic simulation software has been used to simulate the performance of these fractal structured PIFA antennas.

In this paper, low frequency oscillations in power system under the different operating conditions have been solved through conventional power system stabilizer and PID based power system stabilizer. The tuning of the parameters of the PSSs are considered as optimization problem, and the parameters are tuned using genetic search algorithm. Here forth –order linear and non-linear model of the synchronous machine (model 1.1) which includes both the generator main field winding and the damper winding in q-axis is considered for finding out the sensitivity of electromechanical modes of single machine infinite bus system. The effectiveness of automatic voltage controller, and Conventional and PID -power system stabilizer are identified through eigen value analysis and participation factor method. The non-linear simulation results show the effectiveness and capability of two schemes of PSS for power system stability improvement under various disturbances.

The paper presents the modeling, simulation & analysis of Speed Controller for a Brushless DC Motor. Performance comparison between a position sensor and sensorless based speed control is also presented in the paper. Hall effect Sensors have been used for position sensing and back emf based method has been used for determining the position of rotor in position sensorless scheme. The speed controller has been implemented by incorporating PI controller and hysteresis current controller in MATLAB Simulink. Hysteresis current controller was used to generate PWM pulses for inverter switches. IGBT based inverter was used for conversion of DC power to AC power.

This paper is the study on setting up a solar PV system plant and rooftop system in the northern hemisphere of India. It includes brief explanation on structure, calculations based on the approximated data collected from the 5MW plant and maintenance required to get the maximum efficiency of the plant. However many locations around the world have years of weather records that will provide average data which is sufficient for designing a PV systems and if no long term data exists for the chosen site, in that case the availability of sun light and the amount of sunshine can also be estimated with the help of available equipments.

The series of spinnel ferrite substance with chemical composition Cu(1-x)ZnxFe2O4 where 0.365

Congestion in the power system transmission network has been a major constraint towards making active power available to the consumers. One of the conventional and long term methods but capital intensive to alleviating this problem is by adding new, expanding or reinforcing existing transmission facility. In this work, an interim, short term and cost effective measure – the use of TCSC and SVC in enhancing loadability of congested power transmission line was presented. The Nigerian Interconnected Power System – 330 kV bus power transmission network was used as a baseline and NEPLAN – a power system software was used to run load flow analysis on the network in four stages: a baseline load flow analysis on the network to identify areas of constraints, a load flow analysis with TCSC located in-between optimal nodes, load flow analysis with SVC located at optimal nodes and then, a load flow analysis in the presence of TCSC and SVC on the network. The impact of these activities were investigated and the results showed that under baseline condition, low voltage violations occurred at Gombe, Jos, Kaduna, Kano, Kebbi, Maiduguri, Makurdi, and Sokoto bus stations with percentage bus voltage of 65.77%, 72.83%, 79.96%, 62.29%, 89.63%, 65.37%, 79.46%, and 89.07% respectively; well below the reference percentage bus voltage profile of 90%. The combined services of TCSC and SVC as proposed, remedied the violations with a corresponding percentage bus voltages of 94.83%, 99.50%, 96.84%, 99.50%, 99.09%, 94.55%, 95.48%, and 99.50% respectively. With the presence of TCSC & SVC, total active power loss on the network was reduced from 108.76MW to 59.18MW (46%), and total reactive power loss, from 931.19MVar to 505.92Mvar (46%). Loadability was greatly enhanced on the lines with TCSC and the neighboring lines. For instance, in Makurdi-Jos line, there was active power increase from 212.60MW to 300.61MW, creating about 41% capacity margin; and Kaduna-Jos line, from 45.50MW to 132.97MW, about 195% capacity margin. The overall impact is in the network is that overloaded and congested lines were greatly relieved.