16.07.08
Electromagnetic compatibility for the London Underground network
Source: Rail Technology Magazine June/July 2008
There are many new projects and developments being introduced into the London Underground infrastructure including power upgrades, tunnel cooling, signalling improvements, radio and telecommunications system upgrades, step-free access and increased passenger stock to name a few. To help ensure that all legacy and new electrical systems operate together, safely, reliably and free from electromagnetic interference there is a requirement for electromagnetic compatibility to be maintained between all systems.
The electromagnetic environment of the underground railway can be intense due to the many sources of electromagnetic disturbance such as DC traction power supplies, rolling stock systems and radio communication transmitters. The infrastructure and rolling stock also contain sensitive electronic equipment such as signalling and telecommunications. The proximity of these sources and potential victim systems can lead to interference events.
LU requires that equipment, systems and installations comply with EMC Directive 2004/108/EC and UK legislation 2006 No.3418 and that they meet the LU defined set of specific EMC requirements in order to help ensure interference-free operation in the underground’s severe electromagnetic environment.
The LU mandatory Cat 1 standard 1-222 describes the framework necessary to ensure that the EMC aspects of equipment for installation within LU are adequately addressed.
The standards to be applied are listed in the LU Manual of Good Practice G-222, a document which goes into more technical detail on LU’s EMC requirements. The primary set of standards to be applied is the EN50121 series, which define limits for the general railway environment. However, LU have also identified additional EMC standards for their specific environment and these should be complied with as it is the responsibility of the parties involved with installation, design and commissioning to be aware and take account of any electromagnetic environmental influences.
ERA Technology, a part of Cobham plc, has a wealth of experience of EMC for major projects for the underground and provides technical consultancy to help their clients successfully fulfil their EMC obligations. ERA provides EMC management plans which are strategic, scene setting, instructional documents which are supported by EMC control plans which contain ERA’s various qualitative and quantitative studies, analysis, modelling and measurements necessary to close out any EMC risks for new installations and new works.
ERA collates all this information in a project EMC assurance evidence file so that their clients - owner, designer, supplier, contractor - can present evidence that EMC has been considered and that due diligence has been applied. The file also demonstrates compliance with the EMC Directive and UK legislation.
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