Network Rail

Immunity Test Requirements for Lineside Communications Systems - Compliance Date: 4 March 2017
 N NR/L2/TEL/30003 ISSUE 4

Annotation

The process set out in this document applies to equipment which is intended to be connected to lineside telecom copper cables whose parallelism with AC traction systems might exceed 1 km.

It specifies the tests to be applied as part of the product acceptance process to determine the system performance when connected to lineside telecommunications copper cable which is subjected to induced voltages from the AC traction systems under normal and fault conditions. The tests are required in addition to other EMC tests typically carried out by the manufacturer (e.g. EN 50121-4 or EN 61000-6-2). The tests include:

a) low frequency conducted immunity from 15 Hz to 150 kHz- normal conditions;

b) power frequency conducted immunity - fault conditions; and

c) longitudinal conversion loss test. The process applies to manufacturers or suppliers of equipment intended to be connected to lineside copper cables in the railway environment.

NOTE: The tests may be carried out by appropriately certified third parties.

Purpose

Network Rail’s overhead AC electrification infrastructure can induce interference into lineside copper telecommunications cables, which can degrade the performance of equipment that is electrically connected to them. This standard provides the methodology for testing telecommunications equipment’s performance suitability when connected to these interference induced copper cables.

For certain applications where commercial-off-the-shelf (COTS) equipment is adopted, applying the tests set out in this standard establishes whether the equipment will continue to operate without unexpected performance degradation when connected to lineside copper cable in the railway environment. Where failures are identified the risks to the applications can be evaluated.