Power Quality Monitoring and Assessment

During last few years, lots of attention has been paid to the subject of power quality. One of the most important reasons for this attention is the increasing use of electric equipment sensetive to power quality variations. The other reason is the growing use of power electronics in industrial and commercial centers and in household appliances. Due to non-linear charactristics of these devices, harmonic currents are injected into the system, resulting in high harmonic vItage distortion throughout the system. Finally, the emphaiss on having higher efficiencies, has led to growing use of power factor correction ca acitors which in turn can amplify transient disturbances and also increase the level of system harmo nic distortions. In this paper, all the disturbances that cause power quality problems, their sources and effects are discussed briefly. Next, the different parts of a system which has been designed for monitoring and assessment of power quality are explained and few samples of the system output are presented.