Selection of Capacitor Types and Switching Techniques in Distribution Networks with Different Harmonic Levels

Abstract

The present thesis is concerned with one of the most important subjects in distribution networks. The point is to improve the performance of these networks as for the reduction of power losses, and improvement of voltage profile over the feeders. It has been noticed that not only proper sizing & siting of capacitor bank connections in the network improves the performance, but also the type of capacitor banks and their switching technology as well, are of primary importance. It is well documented that the extensive use of electrical energy and advances in power electronics application in industry have resulted in increasing harmonic levels and decreasing power factor in industrial distribution systems. Therefore the search for power factor improvement has been accepted as a major goal for many years. Capacitor banks are recognized to be the most preferred means for power factor enhancement. They provide low cost reactive power source, and reduce the active power loss in the network. This leads definitely, to the increase of life time of all network components. The thesis depends on obtaining real data from industrial loads, obtained by direct measurements, and using this data in building a single model for performing best selection of capacitor bank types for industrial load application with different harmonic levels. The thesis shows that the distribution of capacitor banks near loads within a factory with suitable control has a direct effect on enhancing the power factor. The thesis finally introduces a study of system performance with different types of capacitors at different points in the network. Switching technologies together with higher harmonic effects are examined in distribution network.