In this paper, a three-phase ac-dc converter using three single-phase pulse width modulated active clamped, zero-voltage-switched boost converter in modular approach is presented. The active clamp technique is used for zero-voltageswitching of the main and auxiliary switches. The operating modes, analysis, and design considerations for the proposed converter are explained. To evaluate the performance of the proposed converter, finally simulation and experimental results for a 500-V, 1.5-kW prototype converter are presented. The proposed converter operates at almost unity power factor with reduced output filter size. The output voltage is regulated without affecting zero-voltage-switching, even under unbalanced three-phase input voltages.Index Terms-Active clamp, boost converter, three-phase ac-dc converter, unity power factor.
Power system restructuring throughout the world is undergoing various reforms in the power business. One of the objectives of restructuring process is to allow open access of transmission network to the market participants thereby creating a competitive power market. However it may cause the congestion and further threaten the security of the network. This situation may be avoided by providing the information about available transfer capability of the network to the market players (buyers and sellers). Available transfer capability (ATC) of transmission network is the additional amount of power transfer that can be effected between the buyer bus and seller bus without loss of security. For proper system operations under the various transactions, ATC calculations must be reasonably accurate and fast enough. This paper describes a novel approach of application of sensitivity analysis and power transfer distribution factor for the determination of ATC. Advantages of the proposed approach are also discussed.
Faults in the power system are the most common reason for the occurrence of important power quality problem, voltage sag in the system. Due to increasing use of sensitive and sophisticated control in almost all modern devices at the industrial and residential consumer level, the Voltage sag which causes severe problems to these devices needs to be analyzed. Factors which affect the characteristics of voltage sag as a type of fault in the system, location of fault in the system, X/R ratio of transmission lines, type of transmission as single or double circuit transmission, Point on wave of sag initiation are studied in this paper. PSCAD/EMTDC is used as a simulation tool
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.