The invention relates to an electrified road transport system. The invention also relates to a method for stabilizing a contact line system of an electrified road transport system.
Electric transport systems for transporting goods and persons, having contact lines for supplying electrical energy to vehicles are used in many different variants. Two-pole overhead line systems fed with direct current are conventionally used when using lane-bound supply systems for non-rail-bound vehicles. These have the advantage of a smaller space requirement for the vehicle components and increased safety. The two-pole overhead lines are arranged above electrified traffic lanes and are contacted by electrified utility vehicles with the aid of actively readjusting current collectors, also called pantographs. With the aid of the actively readjusting current collectors, considerable variations, caused by structural system features or temporary environmental conditions, in the horizontal and vertical position above the lane are compensated in comparison to the nominal position.
Horizontal positional deviations between the vehicle and the contact line can result, for example, from a lateral offset of the contact lines with respect to the center of the lane due to chord formation of the contact lines between two adjacent line masts in curves. This results in zig-zag patterns of the course of the contact lines. If the section separators are held by the support cable, then only vertical chain mechanisms are supported in curves, so a zigzag course is formed in the curves, because in order to hold the weight of the section separator, the support cable carrying the section separator has to be arranged directly above it. If in a parallel span there is a change in the contact wires, a lateral offset is produced between the two contact wires. A time-varying offset can be achieved, for example, by a wind power take-off of the contact line in the case of a side wind. In addition, positional deviations due to structural tolerances can also result. Horizontal positional deviations between contact lines and vehicles can also result, however, due to a variable lateral positioning of the vehicle within an electrified lane.
Vertical positional deviations between vehicle and contact line can result from the inertia in the height compensation by means of a non-ideal efficiency of what are known as wheel tensioners and by restoring forces to be overcome at the cantilevers of the power masts. Reduced installation heights of the contact wires result across the road in the case of the continuous electrification on low structures. Utilization of the contact wires, additional loads owing to icing of the contact wires or dimensional tolerances can also lead to a vertical positional deviation.
The horizontal and vertical positional deviations are conventionally compensated by an active horizontal and vertical adjustment of the current collector. A further measure is the use of correspondingly wider carbon wearing strips on the current collectors, which, however, are only worn to a greater extent in a narrow region. This results in a shorter service life of the wearing strips, and this is associated with higher operating and maintenance costs.
In addition, further requirements consist in that the current collector, with travel on non-electrified sections, has to be securely retracted within the horizontal and vertical perimeters of the vehicle in order to rule out contact with other vehicles or structural infrastructure. This results in a significant complexity of the current collector architecture in respect of degrees of freedom, actuators, sensors, control components, which lead to high costs and to a high weight of the current collector.
In Siemens AG, TU Dresden, DLR: ENUBA 2—Gemeinsamer Abschlussbericht [Joint Final Report]; version V3 dated Aug. 31, 2016 contact lines are designed to be skewed in curves. There is also a lowering of the support cable at directional gantries.
Siemens AG: “Mit eHighway in die Zukunft” [Into the future with eHighways]; brochure, 2012 describes an electrified road transport system in which specially adapted overhead lines are installed for speeds of up to 90 km/h.
Kiessling, F: PUSCHMANN, R; SCHMIDER, A.: Fahrleitungen elektrischer Bahnen [Contact lines of electric trains], 3rd edition Erlangen: Publicis Publishing, 2014. Page 126.—ISBN 978-3-89578-407-1 describes the problems of deflection of contact wires by external influences and the stability of the support elements.
DE 10 2011 080 887 A1 describes overhead lines for local transport trains with section separators in the region of overhead line masts.
Powerlines Products GmbH: Powerlines Product Catalogue, section 10.1/1.1, issue 6/2014 Powerlines Products GmbH: Powerlines Product Catalogue. D-45329 Essen, 6/2014. Section 10.1/1.1—company literature, specifies limit values, which must not be exceeded in the event of wear of contact wires.
BUCHHOLD, TH; TRAWNIK, F: Die elektrischen Ausrüstungen der Gleichstrombahnen [The electrical plant of direct current railway systems]. Berlin; Julius Springer, 1931. Pages 292-308.—ISBN 978-3-642-89467-1 describes the application of skewed contacts lines in curves and semi-skewed chain contact lines on straight sections.
One problem is therefore to develop an electrified road transport system, in which positional deviations between vehicle and contact wire are compensated or reduced with less effort.
This object is achieved by an electrified road transport system as claimed in claim 1 and by a method for stabilizing a contact line system of an electrified road transport system as claimed in claim 9.
The inventive electrified road transport system has a contact line system having a plurality of masts and overhead lines suspended on the masts, which comprise support cables and contact wires suspended thereon, and at least one electrified transport vehicle having a pantograph. As is customary, a pantograph should be taken to mean a current collector mounted on a vehicle. An electrified road transport system should be taken to mean a transport system in which the transport vehicles in question travel in a non-rail-bound manner on a route and draw electric current bound in a lane-bound manner. In this case, in contrast to rail-bound systems, lane changes are possible at any time, wherein, however, as a rule, the contact with the power supply line is interrupted for a short period of time. The contact line system has structural modifications for reducing the horizontal and/or vertical positional tolerances of the contact wires. The structural modifications comprise section separators fastened directly to masts or cantilevers of the masts and skewed overhead lines in straight section segments and/or in curves and support cables and/or contact wires having smaller cross-sections and/or higher longitudinal tensile forces.
If the line separators are suspended directly on the masts or cantilevers, it is also possible to install skewed contact lines in curves, and this is associated with an improved positional stability of the contact wires. If cross-sections of the support cables and/or the contact wires are reduced, they offer a smaller target for side winds. Less susceptibility to side winds is accompanied by a smaller deviation of the contact wires from a rest position.
The reduction in the horizontal and/or vertical positional tolerances of the contact wires allows a simplified construction of the current collectors used for electrified road vehicles because, owing to the smaller variation of the relative position of the contact wires to the pantographs of the electrified vehicles, it is possible to reduce demands on the mechanical adjustment of the position of the pantograph to the position of the contact wires. Owing to the lower structural demands on the design of the pantograph, the complexity of the pantograph can be reduced, the number of components thereof can be reduced, the complexity of production of the pantograph can be reduced and a lower maintenance requirement and a longer service life of the pantograph can be achieved. The above-mentioned advantages also contribute to a reduction in the costs of production and operation of an electrified road transport system.
In the inventive method for stabilizing a contact line system of an electrified road transport system, which has a plurality of masts and overhead lines suspended on the masts, which comprise support cables and contact wires suspended thereon, and at least one electrified transport vehicle having a pantograph, structural modifications are made to reduce the horizontal and vertical positional tolerances of the contact wires. Within the framework of the structural modifications section separators are fastened directly to masts or cantilevers of the masts. Skewed overhead lines are installed in straight section segments and/or in curves and support cables and/or contact wires having smaller cross-sections and/or higher longitudinal tensile forces are installed.
The inventive method inventive shares the advantages of the inventive electrified road transport system.
The dependent claims and the following description each contain particularly advantageous embodiments and developments of the invention. In particular, the claims of one claim category can also be developed analogously to the dependent claims of another claim category. Furthermore, within the scope of the invention, the various features of different exemplary embodiments and claims can also be combined to form new exemplary embodiments.
In a preferred embodiment of the inventive electrified road transport system, the structural modifications comprise at least one of the following features:
Increasing the longitudinal tensile forces in the support cables and/or contact wires compared to conventional arrangements also contributes to a reduced variation in the position of the contact wires. So the support cables and/or contact wires withstand the higher tensile forces, it is possible, for example, to select and optimize materials in respect of improved tensile strength. The use of additional line feeders on the masts permits compensation of a weaker electric current flowing as a result of the smaller cross-section of the contact wires and support cables, with part of the electric current flowing through the line feeders. If the anchoring devices of the contact wires are formed as two-span anchoring devices without parallel spans, a lateral offset of the contact wires occurring in parallel spans is thus avoided. In this way, corresponding tolerances in the lateral direction during current tapping can be reduced.
In one embodiment of the inventive transport system, in section segments having skewed overhead lines, the mast distances are unchanged in the section direction compared to mast distances in the case of straight-running overhead lines, so, compared with an arrangement with straight-running overhead lines, reduced horizontal and/or vertical positional tolerances of the contact wires result. In the case of conventional straight-running overhead lines, it is customary to use mast distances in the section direction of approximately 60 m. In the case of an unchanged demand on the positional tolerances of the overhead lines and the contact wires and support cables, mast distances of up to 110 m would accordingly be possible when using skewed overhead lines. In this embodiment, the mast distances should instead be maintained, so, as a result of the better rigidity of the overhead lines owing to the skewed arrangement of the overhead lines, reduced horizontal and/or vertical positional tolerances of the contact wires result compared to a conventional arrangement.
In a special variant of the inventive electrified road transport system, an electrified transport vehicle has a pantograph, which has a reduced working range. The reduced working range, preferably a reduced vertical working range, enables a more uniform current collector run, fewer contact force jumps, reduced wear and therewith, in turn, a longer service life and reduced operating costs of the pantograph. A working range of a conventional pantograph in a conventional electrified transport system should be assumed as a comparison variable for the reduced working range.
The pantograph can also have a horizontal working range which is reduced compared to conventional pantographs. The working range (vertical, horizontal) is the range which the current collector can assume or actively control. Therefore, in this variation a change in the position of the pantograph in the transverse direction is limited. Advantageously, fewer actuators, lower control dynamics up to the elimination of an entire degree of freedom are possible in this embodiment for covering a smaller horizontal working space. Advantageously, it is thereby possible to reduce the complexity of the construction of the current collector.
In a special embodiment of the inventive electrified road transport system the pantograph of the electrified transport vehicle has a reduced positional tolerance. The width of the possible contact area of the current collectors can be reduced, for example, since the possible variation in the positions of the contact wires is limited.
Positional tolerances should in this connection be taken to mean permitted positional deviations of the contact wires. These result from structural tolerances and mechanical effects in the system (wheel tensioner), the wear of the contact wire, vertically acting ice loads and horizontally acting wind loads.
The positional tolerances therefore define a space in which the contact wires are to be expected. This space must be smaller than or equal to the working space of the pantograph so the pantograph can always reliably contact the contact wire.
In a variant of the inventive electrified road transport system the pantograph assumes an invariable position in the lateral and/or vertical direction. In this variant, the technical outlay for the production, maintenance and operation of such a pantograph is particularly low.
In one embodiment of the inventive electrified road transport system the pantograph has a passive air spring system and/or a passive mechanical spring system for vertical position adjustment. A passive spring system has a considerably lower degree of complexity and susceptibility than a controlled pneumatic system used to control the position and movement of a conventional pantograph.
In one embodiment of the inventive electrified road transport system the electrified transport vehicle has an automatic switching device for changing the energy supply of the electrified transport vehicle, which is triggered in the event that the pantograph of the electrified transport vehicle no longer has a secure contact with the contact wire. An automatic switching device of this type is particularly useful when reducing the operating range of the pantograph. The automatic switchover can be carried out, for example, as a function of continuously updated measurement information, which is detected by sensors or is determined by a direct current/voltage measurement. This can therefore comprise either directly the current flow which is present or indirect measurement information, for example in respect of a wind speed or the like. Advantageously, it is possible to thereby compensate for short-term undesired separations of the contact between the pantograph of the transport vehicle and the contact wires such that the switching device switches from a power supply via the pantograph to an energy supply of the vehicle, in particular the traction system, by means of an energy store inside the vehicle. An energy supply inside the vehicle can be achieved, for example, with the aid of an accumulator and/or by the connection of an internal combustion engine. In spite of a reduction in the operating range of the pantograph, and thus a limited adaptation of the position of the pantograph to a variation in position of the contact line, a constant energy supply to the transport vehicles used can be ensured in this way.
The invention will be explained in more detail in the following with reference to the accompanying figures on the basis of exemplary embodiments. In the drawings:
A skewed arrangement of an overhead line is also possible on straight-running section segments.
The arrangement 50 shown in
In step 8. III, the support cables and contact wires are modified in respect of better tensibility. The cross-sections of the support cables and the contact wires are reduced in the process, materials are selected and optimized in respect of improved tensile strength and the support cables and the contact wires are subject to higher tensile stress, so the susceptibility of the arrangement to side wind is reduced.
As a further measure, the mast distances between the overhead line masts are reduced in a step 8.IV, and this also reduces the influence of the side winds on the position of the contact wires and support cables.
In step 8.V, additional line feeders (see
Finally, in step 8.VI, two-span anchoring devices without parallel spans are implemented in the overhead line system. Due to the omission of the parallel spans, the lateral positional tolerance of two adjacent electrically homopolar contact wires, including their lateral movements, is reduced to the lateral positional tolerance of a single contact wire.
A necessary vertical and lateral tolerance range for the contact of a pantograph with the contact wires of an overhead line system is greatly reduced with said measures. The limitation of the tolerance range allows the demands on an adjustment of the pantograph to a position of the contact wires variable in the tolerance range to also be reduced.
The pantograph can therefore be constructed in a simplified manner since fewer actuators can be used to cover the reduced tolerance range. An elimination even of a degree of freedom of movement of the pantograph can potentially be possible in the process. In addition, a simplified spring system can also be used for the pantograph due to the reduction in the tolerance range. The lower level of complexity of the pantograph leads to a smaller number of components, a lower outlay in the production and maintenance of the system, a longer service life of the entire system and to lower operating costs.
In conclusion, it should be pointed out once again that the above-described methods and devices are only preferred exemplary embodiments and that a person skilled in the art can vary the invention without departing from the scope of the invention insofar as it is specified by the claims. As already mentioned, the invention is intended not only for overhead line systems having one line, but preferably also for overhead line systems having two parallel, differently polarized direct current lines. It is also pointed out for the sake of completeness that the use of the indefinite articles “a” or “an” does not preclude the features in question from also being present several times.
Number | Date | Country | Kind |
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10 2017 202 757.6 | Feb 2017 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2018/052675 | 2/2/2018 | WO | 00 |