ESTIMATION AND CONTROL OF HARMONIC CURRENTS IN A.C. TRACTION SYSTEM

Abstract

In the planning of rail road electrification for meeting the future growth of traction system and for efficient operation of electrical locomotive, one has to analyze and compare the electrical performance of the various alternatives. In this report, work has been done on and used the thyristor phase controlled devices for power conversion. Earlier mercury are rectifier and motor-generator(M-G) sets were used for ac to dc conversion, which are bulky and less efficient. Now they have beer replaced by the modern semiconductor devices like SCRs which are more efficient, small in size. In the present work a computer program has been developed to study the power supply condition and performance of the phase controlled devices. This determines the harmonic currents and their phase angles reflected to the utility grid. Lastly for elimination and suppression of harmonics, filter has been designed for low and higher order harmonics. Filter effectiveness has been also evaluated.