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Electrical Engineering is a fascinating area of knowledge and my research interest is drawn towards many facets of this field. The following summarizes the research activities in my professional and academic career.
Research Completed/Ongoing
1. Development of a reliability driven electric supply system for rural Australia
Organization: School of Engineering Systems, Queensland University of Technology, Brisbane, Australia. The project is being carried out in collaboration with Central Queensland University and funded by the Australian Research Council.
Participation: Working as the researcher from Queensland University of Technology, from August, 2008 till present date.
The main aim of the project is to undertake a fundamental study of the distribution system to achieve defined levels of performance with optimization of the resources. Establishing the economic limits to the cross connections based on load density and determining the appropriate voltage level and supply type will also be important part of the project.
2. Power system security enhancement using massively deployed sensors
Organization: Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, Cyprus. The project was carried out in collaboration with Arizona State University, USA, and funded by the Cyprus Research Promotion Foundation.
Participation: Worked as a postdoctoral research associate from October, 2006 till July, 2008.
Modern society relies on the infrastructure of technology, which includes networked computers, interconnected power systems, transportation infrastructure, the financial industry, and other interconnected systems. Control of these systems often relies heavily on measurements disbursed through the system, such as voltage and current measurements in power systems. The cost of sensors and the communications of those sensors to centralized data concentrating facilities used to be the limitations on the amount of data that can be measured and the capability of obtaining situational awareness of the system. However, advances in sensory technology and communications have made the concept of massively deployed sensors more attractive and feasible. The motivation of this research project was to study the technologies of sensors, data gathering, and communications networks for the purpose of enhancing the security and operational capability of the power system grid. In addition, the results of this project are expected to have applications in a range of societal infrastructures, including transportation systems, and computer systems. The enhancement of situational awareness of these systems is expected to lead to greater security. The sensors can play an important role in the control of the system since direct measurements can augment the traditional sensory inputs and the feedback that is used in power systems, thus improving the response of the system. In terms of operation, this project examined the optimal placement of sensors in the network topology to ensure that the most significant measurements are recorded, and to increase the confidence in the estimated states of the system. Finally, sensors were used to enhance the security of the system and protect it against physical catastrophes or malicious attacks. The work included feasibility study of different types of sensors for power system applications, optimal placement of phasor measurement units for power system state estimation, and the design of a wide area control strategy for a power system.
3. A grid-connected hybrid energy system for a typical household in Cyprus
Organization: Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, Cyprus.
Participation: As a postdoctoral research associate and the principal researcher from November, 2006 to January, 2008.
The alarming effects of global warming and greenhouse gas emissions at different parts of the world are calling for eco-friendly sources of energy. Renewable energy systems are finding increasing use in modern power systems due to their non-diminishing abundance, environment-friendliness, and cost-effectiveness. The Republic of Cyprus situated in the Mediterranean Sea depends heavily for its energy production on the oil-fired thermal power stations. In 2004, Cyprus joined the European Union which is aiming at achieving 20% penetration of renewable energy sources in its total energy production by 2020. Cyprus receives a significant amount of solar radiation throughout the year, and recent studies have shown the potential for wind energy in Cyprus. The project aimed at developing a cost-effective hybrid energy system for a common household in Cyprus. In addition to solar and wind energy systems, other renewable energy systems considered were fuel cells and diesel generators, along with battery backups. Sensitivity analysis of the hybrid energy system with respect to varying solar radiation, wind speed, and fluctuating fuel prices was also carried out.
4. Application of artificial neural networks for online voltage stability monitoring and enhancement of an electric power system
Organization: Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John’s, Canada. The research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada.
Participation: Worked as a PhD candidate and the principal researcher on the topic from September, 2002 to August, 2006.
Due to economic reasons arising out of deregulation and open market of electricity, modern day power systems are being operated closer to their stability limits. Power system voltage stability is one of the challenging problems faced by the utilities. Innovative methods and solutions are required to evaluate the voltage stability of a power system and implement suitable strategies to enhance the robustness of the power system against voltage stability problems. This is the motivation behind the research carried out as a part of the PhD program. Artificial neural networks (ANNs) have gained widespread attention from researchers in recent years as a tool for online voltage stability assessment. Two major areas requiring investigation are identified after doing a thorough survey of the existing literature. The first one is the effective method of selecting important features as potential inputs to the ANN. The second one is the feasibility of using a single ANN for monitoring voltage stability for multiple contingencies. In the first phase of the research, a regression-based method of computing sensitivities of the voltage stability margin with respect to different parameters is proposed. Using the sensitivity information, important features are chosen selectively to train separate Multilayer Perceptron Networks (MLP) to monitor voltage stability for different contingencies. In the second phase of the research, an enhanced Radial Basis Function Network (RBFN) is proposed for online voltage stability monitoring. Important features of the proposed RBFN are: (1) the same network is trained for multiple contingencies, thus eliminating the need for training different ANNs for different contingencies, (2) the number of neurons in the hidden layers is decided automatically using a sequential learning strategy, (3) the RBFN can be adapted online, with changing operating scenario, (4) a network pruning strategy is used to limit the growth of the network size as a result of the adaptation process. In the next phase of the research, a sensitivity-based voltage stability enhancement method is proposed, considering multiple contingencies. Considering the limitations of the existing analytical methods, the sensitivities of the voltage stability margin with respect to parameters are found by using the RBFN proposed in the second phase of the research. Using the sensitivity information, correct amounts of generation rescheduling are found by using linear optimization.
5. Development of a computer controlled multi-channel high voltage supply system
Organization: Electronics Division, Bhabha Atomic Research Centre, Mumbai, India.
Participation: Worked as a Scientific Officer and one of the principal researchers in the project from April, 2000 to May, 2002.
The high energy gamma ray telescopes being set up by Nuclear Research Laboratory, Bhabha Atomic Research Centre required a very large number of (~ 1000 nos.) programmable high voltage power supplies for biasing photomultiplier tubes for the detection and characterization of the atmospheric Cerenkov events. These High Voltage (HV) supplies needed to be very compact, lightweight and rugged, as they would be mounted on the base of the moving telescopes. In the new design, high value of the inverter switching frequency was chosen and surface mounted devices were used to achieve overall size and weight reductions. The system consisted of multiple HV modules, each containing 16 independently programmable HV supplies. Each HV module had an on-board micro-controller for doing control and supervisory functions and was interconnected via a serial I2C bus. The HV supplies had built in over voltage/current, thermal overload protections with output voltage readback and adjustable slew rate control facilities. The design of the overall HV system was completed and the performance of the prototype HV modules developed for such applications was tested successfully.
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