Limity pro optimální pouzití elektrickych drenází v zastavěnych oblastech

A detailed analysis of the technical execution and current load of electric tramways revealed that designing the placement and type of electric polarized drainage (EPD) should reflect specific features of the electric tramway in Prague. The evaluation of the existing EPD installations in Prague and the mathematic analysis of the distribution of the reverse traction current flowing in the rail suggested that the existing practice applied to design electric drainage and the drainage equipment used should be modified. The best approach to limit the drainage current and thus to minimize interference turned out to be, when the pipeline runs parallel to an electric tramway, to shorten the pipeline section under drainage by wiring the drainage equipment to all connecting electric drainage boxes, with the reverse cables connected to respective switching station. It was revealed by examination that the application of electric drainage had no alternative in some localities. This approach is perspective also with regard to the fact that medium-pressure pipelines of rather large diameters (DN 500) will not be possible to replace with plastic ones even in the future. Depending on locality, three EPD types, whose main characteristics are given in the paper, are recommended for optimum protection.