Analýza vlivů nesymetrické a nelineární zátěže na energetickou napájecí soustavu

Abstract

Electric traction is a major energy consumer from the power supply system. Traction power consumption can be characterized as dynamic, often unpredictable, time and quantitatively very unstable. During operation of electric traction there is a mutual influence among traction devices, power supply system and other electrical devices connected to a point of common coupling. Characteristic features of the operation of electric single-phase AC traction, 25 kV, 50 Hz are primarily asymmetric loading of three-phase power supply system and the origin of harmonic distortion of drawn traction current. The purpose of the doctoral thesis is the analysis of these phenomena. The doctoral thesis follows the author's diploma thesis, from which draws the results of measurement processing in the traction transformer station and brings new chapters on software modeling of electric power transmission through the power supply system, traction transformer station, contact line to the drive vehicle. The simulation model is analyzed in terms of various operating states during traction power supply in terms of its impact on the power supply system. The model also allows to predict the degree of influence of traction operation on the voltage unbalance factor rate in the power supply system and to evaluate the voltage drops in the contact line at various stages of loading of the traction transformer station. Another part of this dissertation evaluates the benefit of installation of the Scott transformer in traction transformer stations as a technical means for asymmetry reduction. The final part is related to the simulation of connection of additional filter branch to the existing filter-compensating unit in order to reduce the penetration of the 7th harmonic current to the power supply system.