Special requirements in a special networkOne third of the route network of the Rhaetian Railway (RhB) is classified as a UNESCO world heritage site and is located in or on civil engineering structures. This means that the RhB has to invest large sums every year to preserve the substance of the civil engineering structures. The RhB invested around 192 million Swiss francs in its infrastructure in 2015 alone.
It is currently modernizing an essential part of the infrastructure: the energy supply to the lines and vehicles, without which reliable, punctual train services are just not possible. The RhB powers its electric trains on the main lines with an 11 kV single-phase alternating current at a frequency of 16.7 hertz which is supplied by the customary means of overhead lines. This frequency is the same as that on the remainder of the Swiss rail network, although the voltage is 4 kV lower. The energy is transported over medium distances using the railway's own supply network, which runs as a single-phase, three-conductor network with the same frequency of 16.7 hertz, but at a voltage of 66 kV.
The RhB management wanted to be able to modernize and simplify the operation of the systems, to obtain data in greater quantity and detail about the state of the network and the stations, and to improve the overall efficiency of the automation solution, especially for the standby service that has to be able to access the systems at all times for remote maintenance. None of these requirements could be realized with the existing technology, so the RhB decided on a comprehensive retrofit for the switchgear.
Spectacular bridges, numerous tunnels and one of the highest route sections over the Bernina Pass at an altitude of 2253 m above sea level are a testament to the feats of construction accomplished since the railway was founded in 1888. Less spectacular, but essential for the operation of the railway, is the power supply to the route. In the harsh mountain climate, it not only has to be rugged and reliable, but also capable of being quickly brought back into operation after damage caused by wind or snow. Thanks to an integrated solution for the automation and switchgear, the standby service for the traction power supplies can now localize malfunctions more precisely and rectify them more quickly.
In April 2016, the pilot system at Landquart Station became the first of the 14 stations planned to be converted. The existing technology, based on Simatic S5, has been migrated to Simatic S7, and the protective equipment has been modernized with up-to-date Siprotec systems. Furthermore, the mimic diagram previously used for operation in the substations has been replaced by a 19'' Simatic HMI TP1900 widescreen Comfort Panel with touch operation, which was configured in the TIA Portal.
Landquart was selected as the pilot project because the station is one of the RhB's technologically most complex installations. Ursin Gabriel, an engineer in the infrastructure department and one of the project managers at RhB, says that Landquart not only has a substation that supplies and monitors power to the sections between Chur and Küblis, but is also one of the four feeder stations. He is very pleased with the progress of the project so far: "Of course, there are always teething troubles with any pilot project, but together with Repower and Siemens, we have resolved them satisfactorily. We have seen that there is a huge advantage in having one contact for all questions. Obviously, being able to obtain both the automation and the switchgear from Siemens makes it easier for us to handle the project."
On the technical side, the operation of the system in particular has improved considerably. Gabriel adds: "Among other things, we have replaced the mosaic panels in the substations with panels that have touch operation. This makes the work of our local standby teams much easier." This assessment is shared by his colleague, Jakob Jegen, who has now been maintaining the traction power supplies for 26 years, "The new panel is much clearer than the old operator panels. Not only that, we now have a greater quantity of more accurate measured values and data from the route, so that we are better able to localize and narrow down faults."
Obviously, being able to obtain both the automation and the switchgear from Siemens makes it easier for us to handle the project.Ursin Gabriel, Engineering Rhaetian Railway
Interruptions to the power supply are not a common occurrence at RhB but – mainly in the winter half year – heavy snow or strong wind can sometimes bring a tree down onto an overhead line. Maintenance teams then have to be taken quickly to the trouble spot by special diesel locomotives, so that services can be resumed as quickly as possible. Since the modernization, it is apparent that even this task can now be performed better than before.
A fault message, like all other data from the rail network, is sent to the control center, which then informs the traction power supply control rooms and the standby service. From his or her home computer, the employee on standby duty then connects to the monitoring system via the remote maintenance system. Jegen explains, "The entire system has performed better since the modernization. We can now find a fault more quickly, and report it to the maintenance department. Previously, we had to log messages and malfunctions on paper – which was very time consuming. Now all data is recorded and logged automatically, making our job much easier." The automatic archiving of data and messages is also an important innovation for Gabriel, "As a result, we always have all the latest and saved data available, are better able to analyze the causes of faults, and to take appropriate countermeasures when necessary. This will certainly be very beneficial to us in future."
The entire system has performed better since the modernization. We can now find a fault more quickly, and report it to the maintenance department.Jakob Jegen, Maintenance Dept. Rhaetian Railway
Setting course for the future
The project team around Ursin Gabriel is handling the modernization, "So far, we have converted three stations, but we want to have completed the conversion of all the feeder stations and the 15 substations by the end of 2017. With our experienced teams, I am sure that we will make good progress and keep on schedule." By then the RhB will have set the course for the future for this particularly critical part of the infrastructure and will continue on its successful course with a safe and uninterruptible traction power supply.