Cable Study Management

Cable management services to help mitigate induced voltages and transverse/psophometric disturbances affecting safety critical railway equipment.

Railway fixed installations frequently include long signal cables running in close proximity to electrified overhead lines or to high voltage supply cabling.

Problems which can arise

Signal cables can be the victim of induced disturbances, which can give rise to

• Audio frequency transverse voltages, giving rise to psophometric disturbance, and to,
• Longitudinal power frequency voltages; above a certain level, these become hazardous to both personnel and equipment.

It can therefore be necessary to undertake cable studies to model the expected transverse and longitudinal voltages induced on a cable (or group of cables) given a particular traction power feeding arrangement, in both normal running conditions and short circuit events.

On UK railways, psophometric noise is generally limited to 1 mV_P and induced longitudinal, or touch voltage is limited to 645 V (for short-circuit events) to 60 V (continuous), or 25 V (continuous in workshops and Underground environments). EN 50122 details these requirements fully.

How we can help

Eurofins E&E UK has extensive experience in modelling induced voltages and in proposing mitigations.

We can also make measurements of induced voltages over hours or days to verify that predicted values are inside agreed limits.

For more information or to discuss your requirements please contact our York office.