Scientific paper ID 2279 : 2022/3

The object of the survey in the present report is a segment of the tram line running along Bulgaria Boulevard, Sofia, powered by the ‘Motopista’ current-rectifier station through the ‘Emil Markov’ and the ‘Shiroka Laka’ feeders. The electric transport vehicles (ETV), which run along this segment of the track are tram motrices (TM) of the model PESA 120 NaSf, which have the option for recuperative braking. The TM provide transportation service coverage for lines Nos. 7 and 27, which pertain to the Sofia Public Transport network and are managed by the Sofia Electric Transport LLC. The experimental testing was conducted under normal exploitational conditions over the period 20-27 July, 2022 in the territory of the ‘Motopista’ current-rectifier station. Current measurements were made (direct and reverse) through the ‘Emil Markov’ and ‘Shiroka Laka’ feeders, and also voltage measurements were taken at the common power bus. The measurements were taken simultaneously in real time and records of the values were made within a sampling period of 100 ms. The main purpose was to determine the power consumption within this segment of the track in relation to the mode and the scheduling of ETV movements, as well as to determine the amount of the recuperative energy used in the different modes.

The experimental testing produced an ample volume of data. Some of these are presented through graphs and tables in the report. The obtained results were analysed in detail and the extreme values of the voltage and currents were identified in relation to the number of TMs moving along the track segment. The power consumption and the amount of the recuperative energy used within the track segment were determined.