Harmonic Analysis of Addis Ababa Light Rail Transit Traction Converters
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Date
2014-08
Authors
Journal Title
Journal ISSN
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Publisher
AAU
Abstract
Traction power system is the main area of industrial sector where the application of
power electronic technology is widely used. The uses of these devices create
harmonics that cause a serious problem on the proper operation of the system. There
have been different corrective methods proposed by different researchers. Among
them, the AC side passive filters that provide low resistive path to eliminate the
harmonics; and the active filter that produce harmonic currents in equal magnitude
and 180
0
out of phase to suppress it, are the widely discussed ones.
This thesis provides the harmonic analysis of Addis Ababa Light Rail Transit (LRT)
traction system. The analysis is performed on the Lideta rectifier substation. The
traction system is modelled using Matlab/Simulink environment. Based on the data
obtained from Ethiopian Railway Corporation (ERC), simulation is carried out and
compared with the IEEE standard limits.
Taking into consideration the cost and simplicity of the operation, single tuned filters
tuned at 11
th
and 13
th
harmonics and high pass filter adjusted for higher harmonics
currents are designed for the AC side, and LC filter is proposed for the DC side of the
system.
The simulation result comes with significant reduction in harmonic distortion. The
Total Harmonic Distortion (THD) is reduced to 0.80% for the current and to 0.33%
for voltage, which is far below the 5% limits of IEEE standard. In addition to that the
system power factor is improved from 0.77 to 0.99, which avoids the installation of
power factor corrector.
Description
Keywords
Traction power system, converters, harmonic analysis, harmonic filters