ABB 60 - 65 A perfect fit

Line-input-side challenges Since the train is an often fast moving system, the catenary contact is not per fectly stable. Hence, the converter has to compensate for fluctuations in input power. In weak electrification networks, like for instance in some parts of India, adapting to varying line voltages, is an even greater challenge.   Traction converter control should not only optimize the output voltage wave forms for the motors but it should also make sure that the traction chain does not cause perturbations, oscillations or higher harmonics on the input side. In diesel-electric vehicles, the converter control needs to minimize distortions in the generator waveform to reduce wear and optimize energy efficiency. For elec tric trains, line-input control is even more important in order to avoid safety-rele vant interference with signaling installa tions. In certain networks, as described above, good traction converters in oper ation can even have a stabilizing effect on the line voltage level and waveform. An example for these challenges is the system perturbation code in the Norwe gian 15 kV/16.7 Hz rail network. The rail infrastructure agency Jernbaneverket demands a specific damping of low-fre quency oscillations that arise through the load of trains running on long-distance parts of the network and the regulation of small hydropower plants feeding these lines. ABB traction converters, because of their powerful converter control pro gramming, were more than capable of meeting these requirements by simply adapting software already running on converters designed for trains in Switzer land. Test runs in Norway with a Swiss FLIRT train from Stadler Rail convinced the Norwegian State Railways (NSB). To day, ABB has orders for 300 BORDLINE CC750 Compact Converters and 150 ABB traction transformers for NSB ➔ 4.   Designed to fit any vehicle design In most rolling stock projects, the vehicle design imposes challenging constraints on the physical dimensions of traction converters, transformers and motors. Through very compact and lightweight constructions, the ABB equipment gives more freedom for the vehicle design. In principle, traction converters and trans formers can be mounted in the machine room (see the converter in the title pic ture), under the floor ➔ 5 or on the roof of the rail vehicle  ➔ 6. The traction convert er design can also substantially reduce the size and weight of the transformer. How can ABB traction converters achieve this compactness and high power-densi ty? The recipe comprises internal liquid cooling, smart power module design and great care with the construction of the aluminum or stainless steel housing. Re quirements for robustness of traction equipment are extremely tough; hence a wealth of expertise in materials selection and processing, welding and riveting technology, FEM analysis, cooling tech nology and other fields is necessary to achieve the weight reductions that ABB can offer in traction projects. Internal liquid cooling for traction con verters, for instance, is a technology that ABB has developed and optimized with great care in the last ten years. The ad vantages are manifold, ie, the tempera ture distribution in all parts of the con verter is highly uniform, enhancing the lifetime of the power semiconductors. Power modules can be built so small and lightweight that one person can handle them. No machine room or other cooling air flow needs to enter the converter, and control electronics and power modules can be cleanly sealed from ambient dust, dirt and humidity.

Designed for retrofit

In refurbishment projects, the challenges of fitting traction converters to the exist ing vehicle are much tougher than in new designs because all interfaces, such as the train control system, the line-input side, motors, the cooling system, avail able space, and all fixings and connec tions are pre-defined. Nevertheless, these complex projects can have a high return on investment provided the con verter supplier can offer a powerful mod ular platform with strong engineering and project management support. This can be illustrated with the retrofit solution for ICE1 high-speed trains in Germany with ABB converters. More details about this retrofit project can be found on page 70 of this issue of ABB Review.

Nowadays rail vehicles increasingly need to cross borders of different electrifica tion systems, eg, between countries with different DC and AC rail networks or be tween urban transport systems and mainline rail services. Coping with differ ent input line voltages is a particular technical challenge for traction chains. ABB has come up with several smart and versatile solutions for such multi-system trains.

Consider, for example, Italy and Switzer land. Treni Regionali Ticino Lombardia (TILO), a subsidiary of the Swiss Federal Railways (SBB), is an operator of regional train services between Switzerland (15 kV AC 16.7 Hz electrification) and Italy (3 kV DC electrification). Between 2005 and 2009, TILO ordered a total of 31 FLIRT trains (3 MW) from Stadler Rail with ABB traction packages (the transformer was designed by ABB Sécheron and Com pact Converters) that can run in both net works without interruption. The dimen sions and most modules correspond to the pure AC version which SBB has bought for Switzerland in more than 80 trains since 2002. By doing this, SBB and TILO now reap the benefits of optimum service and spare part management, and reduced total fleet cost. It also showcas es the satisfaction of SBB with the ABB solution. The same multi-system traction package design was also ordered by Südtiroler Transportstrukturen in 2007 for eight trains commissioned for service be tween Italy and Austria (15 kV AC). For historical reasons, the mountain rail operator Rhätische Bahn (RhB) in Swit zerland has different line voltages in their network. While most of it is powered by 11 kV 16.7 Hz, the line across the Berni na pass, listed in the UNESCO world In early 2010, the first powerful dual-sys tem mountain trains from Stadler Rail, called “Allegra”, started commercial ser vice after successful test runs in the last six months. For these narrow gauge trains, ABB developed under-floor mount ed Compact Converters that comprise two 350 kW propulsion converters, gal vanically insulated auxiliary converters and a battery charger, all in one very ro bust cubicle. Each train is equipped with four BORDLINE Compact Converters and two under-floor traction transform ers – LOT1250 – designed by ABB Sécheron. Deliveries of 60 converters and 30 transformers will continue into the second half of 2010. A unique market position ABB builds low-voltage and medium voltage power electronic drives for all kinds of applications: to propel ships; power wind tunnels; or control large and small motors in sophisticated industrial processes. These drives save huge amounts of energy, enhance automation, improve process quality and reduce me chanical wear. Related power electronic technology is used to feed energy from wind generators or photo-voltaic plants into the power grid or to stabilize power networks. Continuous innovation in these tion specification and system integration to the train manufacturer. However, le veraging economies of scale, ABB can optimize and standardize on the sub system and module level.