Railway EMI EMC

EMC Requirements for Railway application

The European standard EN 50121-x describes in detail the EMC requirements for railway applications.

Electromagnetic compatibility (EMC) of electrical and electronic systems is an essential requirement for the reliable and safe operation of equipment.  In a rail environment it is apparent that traction power equipment may interfere with signaling systems causing safety critical consequences. So, EMC is one of the requirements to be included in a safety case for the introduction of new rolling stock, locomotives or track maintenance vehicles.

Current railway schemes use rail as a guidance system, the return power conductor in ac or dc railway electrification schemes and is also used as a conductor of low power level coded signals for signaling.

The electromagnetic interference is maximized by the widespread use of inverter driven ac traction motor drives. Further, the railway environment has telecommunication and signaling cables to running  parallel to the traction power supply system, leading to coupling of electromagnetic  disturbances onto these cables. This can cause interference and induce signal distortions

The new EMC directive (2014/30/EU) and the implementing UK regulations,  are further impacting upon the railway. The railway is a ‘fixed installation’ under these regulations and the ‘good-EMC engineering practices’ used for the installation of equipment must be documented and held by a ‘responsible person’ and be available to the enforcement authorities whilst the fixed installation remains in operation. The definition of ‘responsible person’ will affect contractors and infrastructure controllers and will require clarification in contracts for the handover of responsibility and of documentation.

The new directive also affects equipment manufacturers. All equipment carrying the CE marking will require ‘technical documentation’ to be prepared, equivalent to the old TCF (Technical Construction File). The manufacturer can choose for this to be assessed by a notified body.

It is therefore essential to manage EMC to meet the technical, safety and legal requirements from project concept by implementing an EMC management plan. EMC testing must be carried out subsequently to verify that EMC has been achieved.

EN 50121-1.

Railway applications – Electromagnetic compatibility  Part 1: General

EN 50121-2

Railway applications – Electromagnetic compatibility Part 2: Emission of the whole railway system to the outside

EN 50121-3-1

Railway applications – Electromagnetic compatibility Part 3-1: Rolling stock – Train and complete vehicle

EN 50121-3-2

Railway applications – Electromagnetic compatibility Part 3-2: Rolling stock – Apparatus

EN 50121-4

Railway applications – Electromagnetic compatibility Part 4: Emission and immunity of the signalling and telecommunications apparatus

EN 50121-5

Railway applications – Electromagnetic compatibility  Part 5: Emission and immunity of fixed power supply installations and apparatus

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