|Title:||Analysis of Power Quality Issues in Ethiopia Railway Traction System: The Case of Awash-Woldia Project Analysis of Power Quality Issues in Ethiopia Railway Traction System: The Case of Awash-Woldia Project Analysis of Power Quality Issues in Ethiopia Railway Traction System: The Case of Awash-Woldia Project|
|???metadata.dc.contributor.*???:||Mengesha Mamo (PhD)|
Abebe Demisie (Mr.) Co-Advisor
|Keywords:||Power Quality;Railway Traction System;Awash-Woldia Project|
|Abstract:||The economic growth of any country depends on the utilization of energy resources. This paper presents the traction system power quality issues and methods of improvement about harmonics current, voltage unbalance, and power factor problems. Power quality issues in power systems have been increased due to nonlinear loads. To compensate these problems direct power compensator (DPC ) will be proposed in this paper, in which a capacitive coupled hybrid LLC structure is added. The proposed DPC contains back to back converter by giving out the same dc link power and also connected with the secondary side of 132/27.5kV v/v transformer to provide a voltage balance in transmission line. A dual converter with a compensator is employed together with co-phase traction transformers to reduce the current harmonics, telecommunication disturbance, voltage unbalance and power factor problems. Reduction in direct power compensator (DPC ) operation voltage can lead to a decrease in the compensation device capacity, power consumptions, and installation cost. The parameter design procedures for minimum dc voltage operation of direct power compensator (DPC ) are being explored. To inject the same compensating currents to the traction power supply system, the DC bus voltage of the direct power compensator (DPC )could be much lower than that of a conventional railway power conditioner (RPC ). As a result, the cost of the power quality conditioner is reduced. Simulation models are built with a direct power compensator (DPC ) connected to the secondary side of a 132 kV/27.5 kV V/V transformer. Simulation results shows the direct power compensator (DPC ) could compensate reactive power, unbalance voltage and current harmonics simultaneously. According to this research the system voltage and current harmonic distortion without direct power compensator was 6.71% and 26.46% respectively with power factor value of 0.81. But when DPC is used voltage and current harmonic distortion is changed to 0.82% and 1.28% with power factor value of 0.99. Co-phase traction power supply with proposed direct power compensator (DPC ) is therefore, suitable for high-speed traction applications. Keywords: – Co phase traction power supply system, direct power compensator, V/V transformer, minimum dc operation voltage, voltage unbalance, power factor and current harmonics.|
|Appears in Collections:||Railway Engineering|
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