• Railway power supply

    Swiss Federal Railways starts operation of PSI network control system

Swiss Federal Railways (SBB) operates the world's most intensively
used railway network. Serving one million passengers per day, a reliable
power supply and high-availability network control technology is
hugely important. Following acceptance of the final test system, SBB's
network control technology based on PSIcontrol went into full productive
operation at the beginning of 2014.

In the summer of 2010, PSI won the contract to replace SBB's systems for all voltage levels, the transport network and the overhead line network. To win the contract, PSI beat off the challenge of some major international corporations after evaluation of an extensive range of criteria by the client. Four countries in Europe now use PSI network control technology for their railway power supply: Germany, Sweden, Switzerland and the Netherlands.

Intelligent fault management

The replacement of the technology for SBB was precipitated by the existing control technology approaching the end of its life and the previous power breakdown of 2005, which caused a largescale supply failure. This resulted in general calls for intelligent management of faults, including a reduction in the volume of alarms, and fault simulation using load flow calculations, as well as establishment of an effective fallback level for the network control technology.

Basic requirements for new SBB network control systems

The operator's stated objectives were to replace and standardise the existing control systems, optimise fault clearance and troubleshooting, increase the system security in the railway power control system and synchronise and optimise the traction current and energy management processes. In addition to replacement of the existing operating management and network control functions, and ensuring very high system availability for workstations, data centres, data storage and security, the basic requirements also included using the existing SBB-Telecom communication infrastructure, as well as integration into existing business processes such as the office environment, alarm systems, ticketing and sales, etc.

One of the key challenges was the requirement to minimise the risk to the railway power supply under full railway operation during commissioning of the new technology.

PSIcontrol: Extended network controller functions for flexible island detection and optimum power flow.

Expansion and improvement of system performance

In addition, to expand and improve system performance, network security calculations with a preview function had to be implemented alongside multilingual operation, extended network controller functions for flexible island detection and optimum power flow. Other requirements included a training simulator for training and development of the network operating personnel, functions such as post mortem analysis and shutdown planning, a shared data basis for the energy management system and the traction current control system and a standardised link for partners.

The new technology supplied for SBB is a hugely sophisticated control system that fully meets the stipulated requirements and incorporates numerous innovative solutions that competitors are unable to provide.

The network control technology at SBB is split into two areas. The transport network is operated using the energy management system (EMS), which includes the network control. The traction current control system (TCC) is responsible for monitoring and control of the overhead line network. The two subsystems have some shared components, in particular a shared source database, which provides both systems with the data that describes the network. The systems are designed to be multilingual, in this case German, French and Italian. The display and operating language can be changed online for a specific workstation.

Overview of energy management (EMS) and traction current control (TCC) system tasks at SBB.
SBB Amsteg power plant in the canton of Uri.

Energy management system

The energy management system (EMS) has to meet the tough requirements of SBB operations, particularly in terms of the extremely dynamic load profile. Managing any island networks that occur in case of faults is essential. Further challenges include determining power sharing with the traction current level and partners and optimising generation (loss minimisation). The comprehensive integrated network calculations, including previews, support the network operating personnel in identifying and resolving bottlenecks and with shutdown planning.

Traction current control system

The focus of the traction current control (TCC) system is on supporting the numerous switching operations at traction current level. This includes rail-specific control programs for lines, routes and operating points. Intended switching operations can be displayed in a preview along with their effects.

Shared training system

A shared training system allows training and development of new and existing control centre personnel under realistic conditions. As well as normal network conditions, it simulates the protective response as well as faults in primary and secondary equipment, providing trainees with an extremely realistic training experience.

Comprehensive switching order management

The system also includes comprehensive switching order management, integrated into the corporate IT infrastructure. Process monitoring is extensive, using telecontrol technology components from PSI. Both systems, EMS and TCC, are set up at two central locations. There are also additional decentralised workstations with different designs, e. g. control centres and office workstations. Splitting the configuration into different, separate zones, combined with other measures, guarantees a high level of reliability.

The railway power network is extremely
dynamic and requires massively complex
control.

Planning and management process

The high complexity of the technology offered and ultimately implemented is reflected in the project management. Throughout the process, various groups were involved on the client side, including system engineering, network management applications and adjacent departments, and they all had to be coordinated. They were all integrated into a continuous planning and management process, which frequently required extreme efforts due to the high quality standards and tight deadlines required. Across all processes, the central requirement of “no significant impairment and no interruption of railway operations” was the guiding principle.

Quality assurance

The quality requirements were demanding, which had an impact on the project implementation in detail, including the testing and inspection work. Users—network management employees—were incorporated into the quality assurance process at all times, and were involved in release decisions and risk analyses based on detailed checklists. In parallel to the actual introduction of new control systems, SBB also brought in comprehensive organisational changes. The general fault clearing process for all technical equipment was changed from “person-specific” to “process-based”. This had implications for the relevant network control process. A new release management and deployment system was set up, which was adopted as part of the system commissioning.

Operator summary

Implementation of the new SBB network control technology involved some huge challenges. Thanks to extensive coordination between the operator, supplier, users and other parties involved, we managed to introduce the system within the agreed schedule and without impacting ongoing railway operations. One of the key lessons is that both the organisation and the processes have to be able to withstand changes and extensions that can influence production, in this case operation. The project represents an important milestone, not just for the ongoing development of railway power systems and EMS functions at PSI. PSI has been able to acquire priceless experience in a very demanding and exhausting project, and this will help us to handle other large and complex projects with the required quality and at reasonable cost.

The project represents an important milestone, not just for the ongoing development of railway power systems and EMS functions at PSI.