As an example, Siemens is currently installing around 1,300 kilometres of electrical overhead contact lines within Denmark’s rail network, with the company working as part of a consortium for the country’s rail operator, Banedanmark. Due for completion in 2026, this eleven year programme covers nine rail routes and includes the installation of overhead contact lines in a 2x25kV configuration, together with new substations, auto transformer stations and remote control equipment.
This programme provides the perfect case study to demonstrate the advantages that could be realised by electrification programmes in the UK, with the potential to achieve significant cost-savings, efficiency improvements and environmental benefits.
New catenary design
At the heart of the Siemens’ solution is the company’s Sicat SX system. This provides affordable electrification across the design and build processes, offering a minimum 20 per cent cost saving against existing technology. These dramatic savings are achievable as a result of a completely new approach to system design, resulting in fewer structures being required.
The system has been dynamically modelled to achieve 100-metre intervals between structures and two-kilometre tension lengths, meaning that it has much less of an impact on the environment. Crucially, this also reduces track access times for both installation and maintenance, with a much lower requirement for construction resource and plant. Overall, this translates to not only to material savings, but also to faster, easier, cheaper and safer installation, with less manpower required on site and far fewer possessions required in the build phase.
The assemblies are manufactured in a factory-controlled environment and are lighter than traditional UK structures. Siemens has developed a software tool to accurately design the layout for electrification projects, with the cantilevers then being pre-assembled with a quick-fixing device, enabling a more flexible, efficient and cost-effective build programme to be followed.
In Denmark, this led to 40 per cent fewer structures (and foundations) being required and, as a result, the impact of the overhead line equipment on the railway landscape and environment has been considerably reduced. To help lessen the environmental impact even further, it is estimated that around 85 per cent of the system’s components can be sourced within the UK, with assembly fabrication able to be undertaken locally to the project.
Electric trains also offer a number of sustainability benefits to the network, including the ability to store energy through regenerative braking systems – typically 20 to 30 per cent lower carbon dioxide emissions compared to diesel powered trains. With a major weight saving compared to diesel rolling stock, electric trains also provide life cycle benefits to the infrastructure, with reduced wear to the railway.
Compliant with the Technical Standards for Interoperability (TSI) for speeds up to 250km/h, the Sicat system is already successfully operating, not only in Denmark, but also in a number of other European countries, delivering electrified rail networks which allow better acceleration and shorter travel times, as well as lower operating and maintenance costs for the operators.
From a review of the work in Denmark, it is clear that, for the UK, a model could be developed to address some of the challenges that any national electrification programme would face, with the ultimate objective being to produce a safer, more cost-efficient and a less risky approach to delivery. Sicat SX needs fewer foundations per kilometre as it is designed for longer span lengths and, being able to deliver more overhead contact line equipment construction within the UK’s tight midweek possession regime, would bring significant cost savings.
Small footprint SVC
Learning from another network, this time one within the UK itself, London Underground (LU) has awarded Siemens Rail Electrification a contract for the installation of a static VAR compensator (SVC) power quality solution at Greenwich Generating Station.
As world-leaders in power quality solutions, and having supplied over 500 SVC systems globally (61 in the UK alone), Siemens’ latest insulated-gate bipolar transistor (IGBT) technology will be at the heart of the Greenwich system, with the practical, innovative design solution developed to meet the programme’s key requirements.
Normally located externally, the Greenwich SVC is unusual in that it is to be installed inside the building, with Siemens’ modular IGBT technology providing a much smaller footprint than would traditionally be possible.
The bespoke solution delivers a number of other significant advantages. The base IGBT platform used in the SVC system delivers much faster electrical switching than alternative systems and is the same technology platform used in Siemens’ 50-to-50Hz Sitras Static Frequency Converter (SFC). As it is oil-free, with no need for a transformer, it presents a lower fire risk and is more environmentally sound. Sustainability is enhanced through the use of recycled or reused materials, with the system containing 29.5 per cent recycled/reused content, compared to a 15 per cent target set by LU. Once operational, the system is also considerably quieter, with sound power levels measured at the receptors as low as 30dB – and so totally inaudible.
This high-profile project will deliver a solution that will set new standards in power quality equipment on the network. The system will be 99 per cent efficient and will cost less to run and maintain over the life of the asset compared to conventional SVC technologies.
The Siemens team is now working closely with London Underground to make sure the programme is efficient and successful. Work is due to start on site in July 2017, with final commissioning scheduled for the end of 2018.
This article was written by James Goulding, business development manager for Siemens Rail Electrification.