Compensation of Voltage Drops in Trolleybus Supply System Using Battery-Based Buffer Station
07.03.2022
An analysis was prepared by the colleagues of Gdansk University of Technology and Pilsen City Public Transport Company PMDP (Plzeňské městské dopravní podniky a.s., PMDP) within the EfficienCE project about the results of a trial operation of a battery-based buffer station supporting a selected section of trolleybus power supply systems in Pilsen, Czech Republic.
The trial operation was carried out in the framework of EfficienCE project. The buffer station was tested in Pilsen, Czech Republic. Pilsen, with 170,000 inhabitants, has three public transportation systems including three tram lines, nine trolleybus lines and 24 daytime bus lines. The Pilsen City Public Transport Company PMDP’s role in the EfficienCE project was to implement the buffer station in Pilsen in order to verify its efficiency in compensating voltage drops and to validate the possibility to expand the use of battery-assisted trolleybuses. The buffer station was planted next to end stop “Sídliště Bory” of trolleybus lines numbers 14 and 16. The trolleybus power section, to which the buffer station was connected, covers 1.8 km of line 16 and 1.2 km of line 14.
Photo: Buffer station in Pilsen: (a) topography of supply section (based on “mapy.cz”); (b) functional diagram
The buffer station aims to prevent the catenary from excessive voltage drops in a part of the route that is most remote from the traction substation. Compensation of voltage drops is carried out by continuously measuring the catenary voltage and injecting the current into the catenary if the voltage decreases below a preset value. The effectiveness of such a solution was evaluated by the analysis of numerous experimental recordings, both from the buffer station itself and from trolleybuses in operation.
Photo: Battery buffer storage station (PMDP)
Further on, based on the recordings, a utilized battery capacity was estimated and a control method for decreasing the required capacity was proposed. The optimal capacity analysis, supplemented with an evaluation of required output current rating, was used to define the best storage technology for the considered application.
The full publication can be found HERE.
Background photo: PMDP
Author of the article: Mikołaj Bartłomiejczyk and Leszek Jarzebowicz from Gdansk University of Technology and Jiří Kohout from PMDP
