Power quality is an increasingly important issue for all business. A recent study by IBM showed that power quality problems cost US business more than $15 billion a year. The increased interest in power quality has resulted in significant advances in monitoring equipments that can be used to characterize disturbances and power quality variations. The recent increased interest in power quality can be explained in a number of ways. The definition of power quality given in the IEEE dictionary is as follows “Power quality is the set of parameters defining the properties of the power supply as delivered to the user in normal operating conditions in terms of the continuity of voltage and voltage characteristics”. Modern electronic and power electronic devices are not only sensitive to voltage disturbances; it also causes disturbances for other customers. These devices become the source and victims of power quality problems. As such the term power quality is used to define the interaction of electronic equipments within the electrical environm