iosr-JEEE   Volume-3 ~ Issue-4

Abstract: The various optimal capacitor placement techniques on transmission and distributions lines for line losses reduction and enhancement of voltage stability in the power system network have been proposed so far in different papers. Optimal Capacitor placement is an optimization problem which has an objective to define the sizes and locations of capacitors to be installed. This paper focuses on the optimal capacitor placement and sizing problem formulation and analytical as well as heuristic artificial intelligence optimization methods for optimal capacitor placement and sizing. This paper helps the researchers to know about the different methods presented so far for optimal capacitor placement and sizing in transmission and distribution networks so that further work on optimal capacitor placement can be carried out for better results.
Keywords -capacitor sizing, distribution system, heuristic techniques, optimal capacitor placement, reactive power, transmission system, voltage stability.

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Abstract:This paper presents an approach to Embedded Based Flyback Converter with Programmable Switching Frequency for Efficiency Optimization. The fly-back converters are popularly used in digital systems for achieving voltage regulation of dc supply. Normally the switching losses and cost is high in existing system. So here we proposed to develop an embedded based fly-back converter with programmable switching frequency in order to optimize the efficiency. The valley switching technique is used by sensing the valley point of switch voltage with Zero Voltage switching technique. The zero voltage switching technique is used hereto reduce the switching losses.
Keywords: flyback converter, valley switching, efficiency optimization,ZVS

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Abstract:The development of All Electric Aircraft has provided new opportunities in the area of electronic devices and power electronics. The purpose of this paper is to compare the properties of soft-switching converter topologies when used to achieve dc-dc conversion at high-power and high-voltage levels. The circuit investigated in this paper can operate in a soft-switching manner enabling reduction in device switching losses and therewith an increase in switching frequency. the ZVS soft-switching region of a DAB converter with arbitrary operating waveforms. The effect of the junction capacitor of the device and the magnetizing inductance of the transformer are also analyzed. Through the analysis, a group of waveforms for different loading conditions are identified to maximize the ZVS operating region. The results are verified by simulation using real device models.
Keywords:DAB converter, soft switching, flyback converter, ultra capacitor bank.

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Abstract:Admittedly, the shocks from the Nigerian electricity crisis despite several palliative measures by the government have created some wedges in the national socio-economic wheel of development. Unfortunately one major method by the government to beef up productivity is by commissioning new power stations which merely solve the problem in the short run. The technical issues that put out the older plants will no sooner than latter affect the new ones and they also go down. This research analyzes the productivity change in Nigeria's power sector from 1970 – 2010. The Malmquist index with Cobb-Douglas Stochastic Production Frontier function was applied to analyze Nigeria's power generation data within the period in focus. Results obtained showed that the 2005 national electric power reform act produced slight technical improvement. It is expected that this work may assist the power policy makers and regulators to come up with better framework for the full realization of the noble goals envisaged in this act.

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Abstract:This paper deals with the optimal location and parameters of Unified Power Flow Controllers (UPFCs) in electrical power systems. The UPFC is one of the most promising FACTS devices in terms of its ability to control power system quantities. Shunt FACTS devices are used for controlling transmission voltage, power flow, reducing reactive losses, and damping of power system oscillations for high power transfer levels. In this paper the optimal location of a shunt FACT device is investigated for an actual line model of a transmission line having series compensation at the center. As one of the most promising FACTS devices in terms of its ability to control power system quantities, UPFC Effect of change in degree of series compensation on the optimal placement of the shunt FACTS device to get the highest possible benefit is studied. The results obtained shown that optimal placement of the shunt FACTS device varies with the change in the level of series compensation.
Key Words: Optimal placement, Shunt FACTS, Series compensation, Unified power flow controller (UPFC)…

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Abstract:Harmonics present in the three phase converter is the major issue while it is been connected to the electric power distribution system. As the conventional model uses real time switching control, this paper deals with discrete event switching control based on hybrid system theory considering Lyapunov stability. Use of hybrid Controller is new to power electronic applications and hence the converters can provide input currents without distortion and with the unity power factor.
Keywords: Harmonics, Switching Control. Hybrid system theory, Lyapunov

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