Experimental Research of Power Quality at Consumers Getting Electricity from the Line TWR 27, 5 kV of Alternating Current Railways

Abstract

The article deals with results of an experimental research of power quality at the consumer, which receives power from the line TWR (two wire and rail) of AC railways. The main factors that affect the quality of electricity in the line were considered. The analysis and statistical estimation of the data obtained during the measurements were carried out. The reliable operation of electrical equipment and power loss are highly dependent on the quality of electricity and, in the same time, companies have become less tolerant of production stoppages. Power supply of industrial and domestic consumers from the traction system has long been practiced in Ukraine. There are indications that power quality in the system of these consumers is worsens but no conclusive results are available due to the lack of researches. The power for some electrical consumers is obtained from 25 kV bus of traction substations where electric locomotives and traction system creates a negative impact on the voltage quality. On the other hand, the power quality is deteriorated, due to the design of the power line, which consists of two wires and rails. The typical conditions of operating AC traction network when the currents on the three wires of a three-phase system are not equal or are not at an exact 120° phase angle. Also voltage dip and harmonic distortion are significant concerns for consumers. Thus, the negative effect of the transmission line is greater than the effect from equipment of the consumers. A study was made of the power quality in system of non traction consumer. A portable power quality analyser is used to measure current, voltage values and quality parameters. Duration of measurements is 24 hour GOST 13109-97. The mathematical statistics methods are used to analysis total harmonic distortion, voltage magnitude variations and voltage unbalance. Input data is obtained by the measurement under operating conditions of traction substation. During the investigation, the levels of the negative impact of the traction load on the quality of electricity are determined. It was concluded that the power quality does not meet the requirements of standard.