IEC TS 62597:2011 pdf – Measurement procedures of magnetic field levels generated by electronic andelectrical apparatus in the railway environment with respect to human exposure.
Typical constellations of railway routes to be considered are
1) single track line.
2) double Irack line.
3) two double track lines in parallel (f or example one for high speed, one for local traffic),
4) multiple track lines are included in 3).
Simulation can be done either by simulating the current distribution In the conductors or by Injecting currents considering worst case assumptions about current distribution.
NOTE 1 In complex systems the current disiribulion cannot be measwed wIh sufficient accuracy- The tool is usually based on Beot-Savarts law br the magnelic fIeld of each conduclot. Theretoie the tool can be validated at a piacticable place with simple geometry and a small numbe of conduclois
b) Compare the worst case results of simulation/calculation with limits.
c) Verification measurement at 2 places of each of the typical constellations. It is recommended that measurement point(s) is (are) set apart from fixed power supply installation.
Verification measurement can be done by either
— a long time measurement (e.g. 24 h including rush hour) in a place apart from fixed power supply installation (1 km for ac. and d.c. lines or the maximum available distance). Measured magnetic held shall be compared to simulated magnetic field.
— measuring current in each of the conductors and magnetic field at the same time (practicable only at a single tracked line). The measurement results have to be extrapolated to maximum current values.
NOTE 2 A ventication of open line covws tunnels as well. The magnebc fields caused by railway sources can be lower in tnnel as the current distribution may include return paths via fIle reinborcement that improves conpensahoI1.
A.3.3 Level crossIng
Procedure for assessment of level crossing is covered by open line.
A.3.4 Platform
A34.1 General
The procedure is the same as that given for open lines. The worst case model of a platform includes only the two nearest tracks to each side (if existing) In a place apart from fixed power supply installation (1 km for a.c. and d.c. lines or the maximum available distance). The influence of additional tracks can be neglected.
A.3.4.2 Terminal station
Terminal station is covered by platform because of magnetic field compensation due to higher return currents portion in the track of terminal station and low traction current at low speed.
A.3.5 Bridges/underpass
The procedure is the same as that given for open lines. Care has to be taken in modelling the layout of the contact line system (e.g. overhead contact line Itself, line feeders, reinforcing feeders).
A.3.6 Fixed power supply Installation
Simulationlcalculation of magnetic field in fixed power supply installation Is usually
In addition to field emitted from lines and cables, magnetic disturbance due to metal and/or ferromagnetic material have to be taken into account.
Nevertheless an extrapolation at least for the magnetic field of cables is possible after measurement.
a) Classify the different types of fixed installation regarding
— power classes:
— rated voltage:
— layout of cabling:
— type of return current conductor system:
— layout of electric power equipment (field source);
— ground•plan (distance from magnetic field sources to the fenceboundary of the fixed
power supply installation, location related to open railway route).
b) Measurement shall be carried Out only on one fixed power supply Installation of each
different type. Worst case measuring points shall be chosen close to sources of high
magnetic fields. e.g.:
— switchgear close to the active bus bar;
— transformer, rectifier, power inductor, series/parallel capacitor:
— return bus bar (where all return currents are collected).
— cable ducts with high currents;
— fence of fixed power supply installation (close to emission sources as transformer,
cabling or return, current collector).
Railway substations and AC/AC substations are functionally similar and the two different installations may be installed geometrically closed or into the same building.