Dynamic voltage restoration

Project (M.S., Electrical and Electronic Engineering) -- California State University, Sacramento, 2010.There were no problems in quality of power for the past few decades, since it had no effect on majority of the loads connected to the electrical distribution system. An Induction motor???s output is considerably lowered while in operation it is contingent to the phase when there is Voltage sag. Now-a-days, power quality has been a major concern to utilities and customers after the augmented use of advanced electronics such as high efficiency variable speed drive, electronic power controller etc. Frequently occurring ???Voltage sag??? is a prominent power quality disturbance in the distribution system. It is mainly caused by fault in the electrical network or by the starting of a large induction motor. Although, the electric utilities have made ample of investments to improve the reliability of the network, they are incapable of controlling the external factor that causes the fault.\ud \ud \ud On distribution side, for sensitive load applications superior quality and uninterrupted connection of electrical supply are of great significance. The device used to a great extent as a series device is Dynamic Voltage Restorer (DVR) that injects AC voltage in series with the supply voltage sag to maintain the pre fault voltage. For fault cases possible in various situations, simulations on MATLAB TOOL and associated waveforms showing operation of DVR will be carried out to serve the efficacy of our proposed technique.\ud \ud The basic flow of the project would include:\ud \ud i. Basic power quality concepts. Voltage Sag, its occurrence and effects.\ud ii. Propitious choice of DVR from other custom power devices and other equipments\ud used for voltage sag mitigations.\ud iii. DVR construction, functional working and various operating modes.\ud iv. Different working schemes of DVR along with concept of ???Minimal Active Voltage Injection Method???.\ud v. Results of simulation done for various faults in MATLAB and conclusion of the behavior of DVR in 1 phase voltage sags.\ud vi. Views about the above research activity in overall and future use.Electrical and Electronic Engineerin