This book presents theoretical and application topics in power quality in distribution systems.With this book we wished to create a resource that is relevant to the needs of the working Power System engineers by helping bridge the theory and simulation work. A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a mal-operation of end use equipments. Utility distribution networks, sensitive industrial loads and critical commercial operations suffer from various types of outages and service interruptions which can cost significant financial 1oss. With the restructuring of Power Systems and with shifting trend towards distributed and dispersed generation, the issue of Power Quality is going to take newer dimensions. In developing countries like India, where the variation of power frequency and many such other determinants of power quality are themselves a serious question, it is very vital to take positive steps in this direction. The present work is to identify the prominent concerns in this area and hence the measures that can enhance the quality of the power are recommended.

This book deals with analysis and simulation of ZVT based Boost PFC Converter with EMI Filter in PSpice software of version 9.2.The Boost converter of Power Factor Correction (PFC) Circuit is analyzed, designed and then simulated for resistive load. It gives better power factor at the input side and constant voltage and current at the output side. The drawback is the current has more noise i.e. EMI.The power factor is further improved using ZVS technique. In the converter circuit, the active clamping branch composed of a clamping capacitor and an active switch is placed in parallel with resonant inductor. Also, the main switch, the auxiliary switch, the clamping capacitor, the boost diode and the output capacitor form a voltage loop. The power factor is further improved using ZVT technique.The ZVT technique allows the increase in switching frequency without increase in switching losses .ZVT converter operates at a fixed frequency while achieving zero voltage turn on of the main switch and zero current turn off of the boost diode.In this book, it is proposed that ZVT based Boost PFC Converter with EMI Filter is a better solution for power factor improvement in AC to DC Converters

Power electronic devices are non-linear loads that create harmonic distortion and can be susceptible to voltage dips if not adequately protected. The most common economically damaging power quality problem encountered involves the use of variable-speed drives. THREE-PHASE ac-dc conversion of electric power is widely employed in adjustable-speeds drive (ASDs)), uninterruptible power supplies (UPSs), HVDC systems, and utility interfaces with non conventional energy sources such as solar photovoltaic systems (PVs), etc.Traditionally, ac-dc converters, which are also known as rectifiers, are developed using diodes and thyristors to provide uncontrolled and controlled unidirectional and bidirectional dc power. They have the problems of poor power quality. This book is an endeavour towards analyzing the different multi-pulse converters in solving the power quality problem in a three-phase converter system.

Isolated power systems are commonly found in rural and remote areas of the world. These systems represent the alternative to grid connection, where interconnection to a large grid is not viable due to high cost and/or geographical obstacles. Furthermore, power systems such as those onboard of ships, in oil exploration areas and remote mining districts are characterized by limited generating capacity, supplying loads which can consist of significant amount of motor drives and power converters. The use of series compensators (SCs) in improving voltage quality of isolated power systems is to be considered.A control strategy for the SC is to be developed to regulate power flow. This is achieved through phase adjustment of load terminal voltage.Through a phase adjustment technique, we can show that the voltage quality across the terminals of the protected load can be controlled.