The principle of creating a "smart" electricity meter in electric traction networks with stochastic electromagnetic processes

Abstract

Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.