Abstract:
Since last three decades the power quality has become a' subject of great importance. The increase in demand of power supply and change in the nature of load has contributed to the importance of power quality issues. Small hydropower stations are generally located in remote areas. In such areas the grid network is weak due to long distance and relatively high R/X ratio of the distribution cables. With increasing demand being placed on these networks, power quality issues such as poor voltage regulation, voltage sag and harmonic distortion are becoming significant problems. These problems hamper the normal operating condition of small hydro power stations. Upgrading the network to solve these problems and to improve the power quality of small hydro power stations is quite expensive. Recent developments in power electronic technologies have made it possible to create some converter based power compensation systems. The potential of these systems to improve the power quality is high. In this dissertation work the general power quality problems are discussed and' development of power electronics based devices to mitigate the problems of voltage sag and harmonics are done.
In the introductory chapter (chapter 1) the general power quality issues like recent interest in power quality, power quality problems, its sources and effects are discussed. Different international standards related to power quality are discussed. Based on the limits provided these standards, some -mitigation techniques, which are common in
practice, are also discussed.
