The efficiency of introducing onboard reactive power compensators on electric rolling stock of alternating current

Abstract

Questions of energy efficiency of ac electric rolling stock are considered in this paper. Data on the very low power factor in the cargo electric ac locomotives that are in operation on the railways of the Russian Federation on the unmanaged valves, as well as with the reversible converters on thyristors, are provided. The results of operational tests on the railways, which found that almost every kilowatt-hour of active power is accompanied by energy consumption of 1 kVAr h reactive energy; i.e., the value of the power factor varies by approximately 0.7, are given. For example, a simplified power supply scheme of an electric locomotive from a traction substation with identified components of full power is given, as are expressions that allow the influence to be determined of active and reactive power components on energy losses in the power transmission lines. Special attention is paid to the determination of voltage losses in the contact network, which is of particular relevance when driving heavy trains. The results of calculation of power losses in the traction power supply system and the loss of voltage in the contact network, depending on the power factor at different powers of electric locomotives for the average electric operating mode, are given. A vector diagram that shows the prevailing influence of the reactive current component of an electric locomotive on the loss of voltage in the contact network is provided. On the basis of the analysis, it is found that positioning devices of reactive power compensation (RPC) directly on an electric rolling stock is the most effective way to improve the power factor on the electric current collector of an electric locomotive and reduce the power consumption for the traction of trains. The results of tests and trial operation of electric locomotives equipped with a onboard adjustable reactive power compensator are given.