CLC/TS 50562:2011

SLOVENSKI STANDARD
01-oktober-2011
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Railway applications - Fixed installations - Process, measures and demonstration of
safety for electric traction systems
Bahnanwendungen - Ortsfeste Anlagen - Prozess, Maßnahmen und Nachweisführung
für die Sicherheit in der Bahnstromversorgung
Applications ferroviaires - Installations fixes - Processus, mesures et démonstration de la
sécurité pour les installations fixes de traction électrique
Ta slovenski standard je istoveten z: CLC/TS 50562:2011
ICS:
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CLC/TS 50562
SPÉCIFICATION TECHNIQUE
August 2011
TECHNISCHE SPEZIFIKATION
ICS 29.280
English version
Railway applications -
Fixed installations -
Process, measures and demonstration of safety for electric traction
systems
Applications ferroviaires -  Bahnanwendungen -
Installations fixes - Ortsfeste Anlagen -
Processus, mesures et démonstration de Prozess, Maßnahmen und
la sécurité pour les installations fixes de Nachweisführung für die Sicherheit in der
traction électrique Bahnstromversorgung

This Technical Specification was approved by CENELEC on 2011-05-24.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 50562:2011 E
Contents
Foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 7
4 Safety process . 9
4.1 General. 9
4.2 System definition . 11
4.3 Hazard identification . 11
4.4 Risk assessment . 12
4.5 Measures . 12
4.6 Evaluation . 12
4.7 Demonstration of safety . 12
5 Generic risk assessment . 13
6 System definition . 13
6.1 Electric traction system . 14
6.2 Substations and switching stations . 14
6.3 Contact line system . 16
6.4 Return circuit . 16
6.5 Interfaces of the electric traction system . 17
6.6 Interfaces to substations and switching stations . 17
6.7 Interfaces to contact line system . 18
6.8 Interfaces to return circuit. 19
7 Hazard identification . 20
8 Measures . 20
8.1 General. 20
8.2 Substations and switching stations . 21
8.3 Contact line system . 22
8.4 Return circuit . 22
9 Safety evaluation for the reference system . 22
Annex A (informative) Hazard log resulting from the generic risk assessment . 24
A.1 General. 24
A.2 Risk assessment process . 24
A.3 Hazard Log . 26
Annex B (informative) Abbreviations and acronyms . 42
Annex C (informative) Documents and standards correlated to this document . 43
Bibliography . 47

– 3 – CLC/TS 50562:2011
Figures
Figure 1 – Safety process for conventional electric traction system . 10
Figure 2 – Electric traction system and its interfaces . 14

Tables
Table 1 – List of foreseeable top-level hazards and accidents . 11
Table A.1 – List of foreseeable top-level hazards and accidents . 25
Table A.2 – Fields of hazard log . 26
Table A.3 – Substations and switching stations . 27
Table A.4 – Control and protection, hardware components . 28
Table A.5 – Control and protection, software. 31
Table A.6 – Contact system . 33
Table A.7 – Return circuit. 36
Table A.8 – Standards referenced in hazard log . 37
Table B.1 – Abbreviations and acronyms . 42
Table C.1 – List of correlated documents and standards . 43

Foreword
This Technical Specification was prepared by SC 9XC, Electric supply and earthing systems for public
transport equipment and ancillary apparatus (Fixed installations), of Technical Committee CENELEC
TC 9X, Electrical and electronic applications for railways.
It was circulated for vote in accordance with the Internal Regulations, Part 2, Subclause 11.3.3.3 and was
approved by CENELEC as CLC/TS 50562 on 2011-05-24.
The following date is proposed:
– latest date by which the existence of the CLC/TS

has to be announced at national level
(doa) 2011-11-24
__________
– 5 – CLC/TS 50562:2011
1 Scope
This Technical Specification defines the process, measures and demonstration of safety for the electric
traction systems of
– railways,
– guided mass transport systems,
– trolleybus systems.
The systems can be elevated, at-grade and underground.
It does not apply to
– underground mine traction systems,
– cranes, transportable platforms and similar transportation equipment on rails, temporary structures
(e.g. exhibition structures) in so far as these are not supplied directly or via transformers from the
contact line system and are not endangered by the traction power supply system,
– suspended cable cars,
– funicular railways,
– magnetic levitated systems,
– railways with inductive power supply without contact system,
– railways with buried contact system that is required to be energised only below the train to ensure
safety,
but it can support the safety considerations of such systems as far as applicable.
This Technical Specification refers to standards and common practice to demonstrate safety including the
functional aspects.
This Technical Specification applies to the erecting of new lines and to all significant changes of existing
lines.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 50110 (all parts), Operation of electrical installations
EN 50119:2009, Railway applications – Fixed installations – Electric traction overhead contact lines
EN 50122 (all parts), Railway applications – Fixed installations – Electrical safety, earthing and the return
circuit
EN 50122-1:2011, Railway applications – Fixed installations – Electrical safety, earthing and the return
circuit – Part 1: Protective provisions against electric shock
EN 50123 (all parts), Railway applications – Fixed installations – D.C. switchgear
EN 50124 (all parts), Railway applications – Insulation coordination

CLC/TR / EN 50126 (all parts), Railway applications – The specification and demonstration of Reliability,
Availability, Maintainability and Safety (RAMS)
CLC/TR 50126-2:2007, Railway applications – The specification and demonstration of Reliability,
Availability, Maintainability and Safety (RAMS) – Part 2: Guide to the application of EN 50126-1 for safety
EN 50152 (all parts), Railway applications – Fixed installations – Particular requirements for a.c.
switchgear
EN 50153, Railway applications – Rolling stock – Protective provisions relating to electrical hazards
EN 50163, Railway applications – Supply voltages of traction systems
EN 50367, Railway applications – Current collection systems – Technical criteria for the interaction
between pantograph and overhead line (to achieve free access)
EN 50388, Railway applications – Power supply and rolling stock – Technical criteria for the coordination
between power supply (substation) and rolling stock to achieve interoperability
CLC/TR 50488, Railway applications – Safety measures for personnel working on or near overhead
contact lines
EN 60255 (all parts), Measuring relays and protection equipment (IEC 60255, all parts)
EN 60664 (all parts), Insulation coordination for equipment within low-voltage systems
(IEC 60664, all parts)
EN 62271-1:2008, High- voltage switchgear and controlgear – Part 1: Common specifications
(IEC 62271-1:2007)
EN 62305 (all parts), Protection against lightning (IEC 62305, all parts)

– 7 – CLC/TS 50562:2011
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
contact line system
support network for supplying electrical energy from substations to electrically powered traction units,
which covers overhead contact line systems and conductor rail systems; the electrical limits of the system
are the feeding point and the contact point to the current collector
NOTE The mechanical system may comprise
– the contact line,
– structures and foundations,
– supports and any components supporting or registering the conductors,
– head and cross spans,
– tensioning devices,
– along-track feeders, reinforcing feeders, and other lines like earth wires and return conductors as far as they are supported
from contact line system structures,
– any other equipment necessary for operating the contact line,
– conductors connected permanently to the contact line for supply of other electrical equipment such as lights, signal operation,
point control and point heating.
[EN 50119:2009, 3.1.1]
3.2
conventional electric traction system
system constructed, operated and maintained according to relevant standards and common practice
3.3
current collector zone
CCZ
zone whose limits are in general not exceeded by an energized collector no longer in contact with the
contact line or broken collector and its fragments
[EN 50122-1:2011, 3.5.10]
3.4
electric traction system
railway electrical distribution network used to provide energy for rolling stock
NOTE The system may comprise
– contact line systems,
– return circuit of electric traction systems,
– running rails of non electric traction systems, which are in the vicinity of, and conductively connected to the running rails of an
electric traction system,
– electrical installations, which are supplied from contact lines either directly or via a transformer,
– electrical installations in substations, which are utilized solely for distribution of power directly to the contact line,
– electrical installations of switching stations.
[EN 50122-1:2011, 3.4.1]
3.5
electrical safety
freedom from unacceptable risk of harm caused by electrical systems
[EN 50122-1:2011, 3.1.1]
3.6
overhead contact line zone
OCLZ
zone whose limits are in general not exceeded by a broken overhead contact line
[EN 50122-1:2011, 3.5.9]
3.7
return cable
conductor connecting the running rails or other parts of the return circuit to the substation
NOTE Similar to IEC 60050-811-35-04.
[EN 50122-1:2011, 3.3.5]
3.8
return circuit
all conductors which form the intended path for the traction return current under operation and fault
conditions
NOTE The conductors may be
– running rails,
– return conductor rails,
– return conductors,
– return cables.
[EN 50122-1:2011, 3.3.1, mod.]
3.9
return conductor
conductor paralleling the track return system and connected to the running rails at periodic intervals
[EN 50122-1:2011, 3.3.3]
3.10
switchgear and controlgear
general term covering switching devices and their combination with associated control, measuring,
protective and regulating equipment, also assemblies of such devices and equipment with associated
interconnections, accessories, enclosures and supporting structures
[EN 62271-1:2008, 3.1.1]
3.11
(effective) touch voltage
U
te
voltage between conductive parts when touched simultaneously by a person or an animal
NOTE 1 The value of the effective touch voltage can be appreciably influenced by the impedance of the person or the animal in
electric contact with these conductive parts.
[IEC 60050-195-05-11]
NOTE 2 The conductive path through the body is conventionally from hand to both feet (horizontal distance of 1 m) or from hand
to hand.
[EN 50122-1:2011, 3.1.3]
3.12
track circuit
electrical circuit of which the rails of a track section form a part, with usually a source of current connected
at one end and a detection device at the other end for detecting whether this track section is clear or
occupied by a vehicle
NOTE In a continuous signalling system, the track circuit may be used to transmit information between the ground
and the train.
– 9 – CLC/TS 50562:2011
4 Safety process
4.1 General
The design, construction, operation and maintenance of electric traction systems follow the relevant
standards to ensure safety. The safety process itself follows CLC/TR / EN 50126 series over the
complete life cycle.
This clause describes how to
– define the subsystem electric traction system and the relevant interfaces,
– identify hazards,
– apply measures,
– demonstrate an acceptable level of safety.
For the application of this Technical Specification, the differences of the system under consideration and
the reference system described in Clause 6 shall be analysed. The results in terms of measures that are
identified for the reference system shall be evaluated regarding their applicability for the system under
consideration. The latest versions of the relevant standards shall be considered.
The generic process, intended to be applied to conventional electric traction systems, is a process
tailored from CLC/TR / EN 50126 series and it consists of the following steps as shown in Figure 1.

System Definition
Hazard
Identification
Risk assessment
Mitigations Measures
Evaluation
No
acceptable
risk?
YES
Demonstration of
safety
Figure 1 – Safety process for conventional electric traction system
The steps in the safety process are as follows:
– system definition;
– hazard identification;
– risk assessment;
– 11 – CLC/TS 50562:2011
– measures;
– evaluation;
– mitigations in case of non acceptability;
– demonstration of safety.
4.2 System definition
The electric traction system and its interfaces shall be described in a clear and manageable way.
The system may be structured in subsystems as far as it is necessary. The main functions and
components as well as the interfaces shall be included in the system definition. Application conditions
shall be documented and taken into account.
4.3 Hazard identification
A hazard identification shall be performed and results in a list of system hazards.
The hazard identification shall start with the following list of top-level hazards (see Table 1), to ensure that
the basis for the identification of system hazards is comprehensive.
A top-level hazard describes a generic situation that could lead to an accident and where only fortunate
circumstances may prevent an accident. A system hazard describes the reasons, how a top-level hazard
reasonably could be caused by the technical system.
Table 1 – List of foreseeable top-level hazards and accidents
Top-level hazard Foreseeable accident Identification
code of
foreseeable
top-level
hazard/accident
Access to voltages exceeding the limits for Injury due to electric shock A1
the touch voltage according to EN 50122-1
Relative movement between objects and Injury due to striking / collision A2
persons in direct vicinity
Unexpected or heavy acceleration or Injury due to striking / collision with A3
deceleration of persons surroundings or due to slipping, tripping
and falling
Exposure of persons to heat Injury due to fire, heat, arcs A4
Exposure of persons to hazardous amount Injury due to smoke, toxic substances A5
and duration of smoke or toxic substances
(local regulations)
Exposure of persons to severe pressure Injury due to explosion, overpressure A6
waves approaching
Exposure of persons to electromagnetic Injury due to electromagnetic fields or A7
fields or interferences (WHO limits, local interference
regulations)
Inappropriate design or condition of Injury due to falling parts, trapping, A8
equipment clamping, cutting
Excessive sound levels Injury due to reduction or loss of hearing A9

The following groups of persons shall be taken into account during the hazard identification:
– PAX
passengers of the railway. Characteristic: not expecting a risk;
– STAFF
railway staff, civil workers for railway construction, search and rescue etc. Characteristic: awareness
that there is a risk when entering electrical rooms or the vicinity of tracks, power lines and contact
systems;
– PUB
general public, e.g. neighbourhood, passer-by, but not passengers. Characteristic: not expecting a
risk;
– OTHERS
trespasser, vandals etc. This group is aware of the risks when entering the vicinity of tracks, power
lines and contact systems.
4.4 Risk assessment
The identified system hazards shall be assessed regarding the foreseeable accidents and groups at risk.
4.5 Measures
The measures according to the relevant standards and common practice shall be applied to the system
under consideration.
4.6 Evaluation
The applicability of the identified measures shall be evaluated. Formally, the evaluation could be a
statement that the identified measures are suitable for the close out of the identified hazards. The basis
for the conclusion shall be outlined. If the hazard close out for one or more hazards is not successful the
feed back path as per Figure 1 leads to the review of process steps and the identification of mitigations as
applicable.
4.7 Demonstration of safety
The demonstration of safety is intended to document the implementation of the applicable standards and
identified measures.
While applying this document, the safety demonstration shall be done as follows:
– formal statement that the Technical Specification CLC/TS 50562 is applied;
– formal statement that the system under consideration is equivalent to the reference system. By this,
it is accepted that the same hazards are applicable as identified in this Technical Specification.
In case of differences the differences have to be described with related argumentation that the same
hazards and measures respectively apply;
– listing of all measures that are assessed to be applicable to the system under consideration as per
Clause 8;
– tailoring of the applicable measures regarding scope and responsibility of the applicant including
related argumentation;
– listing of all measures within the scope and responsibility of the applicant that were modified including
related argumentation;
– documented evidence or argumentation for the successful implementation of the measures within the
scope and responsibility of the applicant shall be given;

– 13 – CLC/TS 50562:2011
– formal statement that all measures within the scope and responsibility of the applicant have been
implemented successfully making reference to the documented evidence or argumentation;
– formal listing and handing over of all remaining measures to support the employer or entity
responsible for taking over and merging of the safety documentation of different subsystems and
organisations.
Preferably, for the documented evidence or argumentation, the safety demonstration shall give the link to
the project documentation but not repeat or summarise content. Such project documentation can for
example comprise
– engineering input data (environmental conditions and isokeraunic level, field of application etc.),
– O&M manuals (intended use, instructions to use, basic switching procedures etc.),
– operational documentation (Operator's supplementary documentation to the O&M manuals),
– drawings,
– wiring manuals,
– equipment documentation (equipment drawings, O&M manual, T&C manuals etc.),
– test reports (routine or factory acceptance tests of equipment, commissioning test reports etc.),
– studies and calculations (insulation coordination, protection coordination, earthing concept, load flow,
short circuit calculation, dimensioning of components etc.),
– etc.
The complete set of documents and arguments ensures that the system is safe. The safety
demonstration shall be based on the quality management of the applicant, especially regarding the
traceability of measures over future modifications.
5 Generic risk assessment
For this Technical Specification, a generic risk assessment has been performed for the generic electric
traction system and related subsystems identified in Clause 6. The system hazards that could lead to the
top-level hazards and foreseeable accidents listed in Clause 4 have been identified and documented in
the tables in Annex A. For each hazard, the measures have been listed in the same tables. The
measures that are common practice are summarised in Clause 8. Based on long experience in the field of
electric traction systems the residual risk is considered as broadly acceptable if compliance with the
applicable measures is achieved.
A single component may fail in performing the intended function. In general, a single point failure shall not
cause an incident leading to injuries or fatalities with some exceptions or limitations. The residual risks
are broadly accepted, as there was no incident reported in large networks over many years of operation.
EXAMPLE 1 With a high percentage the breakage of a contact system, e.g. catenary wire, leads to a short circuit. To ensure this,
there are certain requirements regarding earthing and bonding e.g. of adjacent structures like fences. The short circuit is detected
and switched off. The time between the loss of mechanic integrity and the switching off is an inevitable time at risk. There is a small
residual risk that the catenary wire may break undetected without causing a short circuit.
EXAMPLE 2 A switchgear for feeding the contact system may not be able to switch off a short circuit caused by a switchgear
failure. The next back up level switchgear will switch off the current, but will need more time. Components like cables or catenary
wires are rated for this scenario; nevertheless, there is a risk that the permissible short-term touch voltages are not maintainable
during those rare and short events.
The measures resulting from this generic risk assessment can be considered as a Code of Practice for
the design, operation and maintenance of electric traction systems within the scope of this Technical
Specification. The measures establish an adequate risk reduction with regard to the hazards identified.
6 System definition
The following system definition describes the reference system for the application of CLC/TS 50562.

6.1 Electric traction system
6.1.1 Function
The electric traction system controls, converts and transmits electric energy to the trains and other
installations along the line via the contact line system and return circuit.
6.1.2 Equipment
The electric traction system comprises the following main installations and components including their
auxiliary power supply as outlined in Figure 2. The nominal voltage of the electric traction system is in
accordance with EN 50163.
Figure 2 – Electric traction system and its interfaces
The subsystems are
– substations and switching stations including control and protection,
– contact line system,
– return circuit.
6.2 Substations and switching stations
6.2.1 Function
6.2.1.1 Introduction
The function of the substations or switching stations is the conversion, switching, control, protection and
interlocking of electric traction power; in detail:
– to connect supply levels electrically;
– to ensure a sufficient galvanic separation of supply levels where necessary;
– to transform the level of voltage or frequency into the level of electrical power required for the
application fed by the relevant substation;

– 15 – CLC/TS 50562:2011
– to ensure that sections of the subsequent contact line system can be electrically connected or
isolated due to the operational requirements or due to maintenance reasons;
– to react on voltages or currents outside of the permissible limits;
– to enable regenerative braking to the feeding network where applicable;
– to store traction power in wayside energy storage devices where applicable;
– to manage the configuration of the electric traction system according to the necessities of the railway
operation by control, protection and interlocking.
6.2.1.2 Control
The function of the control equipment is to enable the operation. It can comprise
– control for the operation of the switchgear by several handling levels, e.g. mechanical switching, local
switching and remote switching,
– automatic functions as auto-reclose, synchro-check, line test,
– data acquisition and recording for supervision and monitoring,
– general switching off.
6.2.1.3 Protection
The function of the protection equipment is to provide protection against process values outside the
permissible range in case of operation and fault conditions, e.g. over current or over and under voltage.
The main aim is to prevent damage of equipment. For an accident, it is at least necessary that a failure in
the system occurs, the protection function fails on demand and a person has to be in the relevant area.
6.2.1.4 Switchgear interlocking
The switchgear interlocking supports the switching activities of the staff in order to avoid switching
activities that could cause unintended status.
6.2.2 Equipment
The substation and switching station equipment for conversion and switching can comprise
– transformers,
– rectifiers, inverters and frequency converters,
– switchgear, e.g. circuit breakers, isolators, sectioning and earthing switches,
– cables and conductor bars,
– surge arrestors,
– resistors, capacitors and reactors,
– installations for short circuit current limitation,
– control and protection equipment,
– measurement equipment like voltage and current transducers,
– connections to the return circuit,
– voltage limiting devices,
– earthing installations and equipment,
– wayside energy storage device.
The control, protection and interlocking equipment can comprise
– electronic hardware and software for control, protection and switchgear interlocking,
– mechanical switchgear interlocking,
– fuses for control and protection installation,

– sensors for the measurement,
– human machine interface (HMI),
– interface to remote control,
– communication cabling inside the electric traction system.
6.3 Contact line system
6.3.1 Function
The contact line system distributes energy along the line together with the return circuit. The contact line
system is a live part and conducts the currents for traction and regenerative braking between substation
and current collectors of rolling stock and other consumers.
6.3.2 Equipment
The contact line system equipment can comprise
– contact line, e.g. overhead contact line, third rail,
– foundations and wall anchoring,
– masts and their fixing elements,
– portals and other cross spans,
– cantilevers, suspension and support for conductor rails,
– tensioning devices and dilatations,
– feeders,
– negative feeders for auto transformer systems,
– return feeder for booster transformer systems,
– cables,
– switches,
– isolators,
– transformers,
– section insulators,
– sections for system separation or phase change over.
6.4 Return circuit
6.4.1 Functions
The return circuit collects and conducts the return currents for traction and regenerative braking between
substation and rolling stock and other consumers.
6.4.2 Equipment
The return circuit consists of all conductors that form the intended path for the traction return current.
Therefore parts of the return circuit can be allocated to different systems of railway applications. The
return circuit can comprise:
– running rails,
– return conductor rails,
– return conductors,
– return cables,
– impedance bonds,
– insulating rail joints.
– 17 – CLC/TS 50562:2011
6.5 Interfaces of the electric traction system
6.5.1 General
Interfaces of the electric traction system taken into account are
– remote control for electric traction system,
– rolling stock and electrical installations fed by the contact line system,
– track,
– signalling,
– railway related communication systems,
– high voltage installations,
– conductive equipment in the current collector zone (CCZ) and overhead contact line zone (OCLZ),
– civil and metallic structures,
– installations within the railway boundary.
6.5.2 Remote control of electric traction system
Transmission of control signals between different locations, e.g. OCC, substations etc.
Aspects: standards of communication and interface equipment, e.g. EN 60870-5-104
6.5.3 Installations in the railway boundary
Technical influence of the electric traction system to or from systems outside of the railway system,
e.g. by
– installations with EMC-sensitive equipment, e.g. hospitals or computer centres,
– other power supply systems in the vicinity like national grids,
– other railways with other electrical system or non electrified railways,
– pipelines e.g. for gas or oil,
– communication systems and power cables,
– storage of dangerous goods.
The installations within the railway boundary can be influenced by the presence of the electromagnetic
fields of substations and switching stations, related cables and contact line system.
Aspects: Existing installations within the railway boundary shall be taken into account during the design,
installation and modification of an electric traction system. New or modified installations within the railway
boundary shall take existing electric traction systems into account. Obvious future changes on both sides
shall be handled accordingly.
6.6 Interfaces to substations and switching stations
6.6.1 Rolling stock and electrical installations fed by the contact line system
Power characteristics of rolling stock in motoring and regenerative braking (static and dynamic, stability)
Aspects: permissible load, unbalance, harmonics, quality of power, handling of internal faults like short
circuits, protection coordination

6.6.2 Track
Power characteristics of track side consumers
Aspects: permissible load, unbalance, harmonics, quality of power, handling of internal faults like short
circuits
6.6.3 Signalling
None.
Assumption: sufficient distance between substation and signalling equipment
Aspects: None
6.6.4 Railway related communication systems
None.
Aspects: earthing requirements
6.6.5 High voltage feeding network
Transfer of electric energy between supplying network and electric traction power supply system.
Exchange of electric energy at the terminations of the incoming feeder of the substation
Aspects: protection coordination, permissible load, unbalance, harmonics, quality of power, handling of
internal faults like short circuits
6.7 Interfaces to contact line system
6.7.1 Rolling stock and electrical installations fed by the contact line system
Rolling stock and wayside equipment fed by the contact line system. Exchange of electric energy at
mobile or stationary interconnection points like pantographs or terminations; e.g. for the air condition of
rolling stock in parking position
Aspects: permissible load, handling of inherent short circuits, current collectors and their characteristics,
dynamic envelope
6.7.2 Track
Running rails and related superstructure. Geometry of assembly to ensure guidance to rolling stock and
by that also the correct position of the current collectors of rolling stock.
Aspects: position of contact wire and supporting structures (masts, portals .) with respect to the track
6.7.3 Signalling
Installations of signals on contact line supporting structures, signalling equipment within the OCLZ and
CCZ
Aspects: permissible mechanical loads, clearance to live equipment, electromagnetic interference

– 19 – CLC/TS 50562:2011
6.7.4 Communication systems
Communication equipment installed in the vicinity or within the OCLZ and CCZ
Aspects: permissible mechanical loads, clearance to live equipment, electromagnetic interference
6.7.5 High voltage feeding network
Crossing with overhead lines, parallel routes of overhead lines, power cables and contact lines
Aspects: electromagnetic interference, distance between installations
6.7.6 Conductive equipment in the CCZ and OCLZ
Presence of buildings or conductive equipment in the current collector zone or in the overhead contact
line zone
Aspects: voltage propagation
6.8 Interfaces to return circuit
6.8.1 Rolling stock and electrical installations fed by the contact line system
Transfer of return currents from wheel-sets or current collectors
Aspects: earthing and bonding requirements
6.8.2 Track
Running rails can form part of the return circuit.
Aspects: Continuity of return circuit, electrical dimensioning of running rails and connectors, rail potential.
6.8.3 Signalling
Track circuits, axle counters.
Aspects: electromagnetic interference, harmonics, induced voltages, earthing and bonding
6.8.4 Communication systems
Communication equipment installed in the vicinity of return circuit
Aspects: electromagnetic interference, harmonics, induced voltages, earthing and bonding
6.8.5 High voltage feeding network
Transfer of return currents in case of operation and faults
Aspects: earthing and bonding
6.8.6 Conductive equipment in the CCZ and OCLZ
Transfer of return currents in case of operation and faults
Aspects: earthing and bonding
6.8.7 Civil and metallic structures
Transfer of return currents in case of operation and faults. Conductive equipment within civil or metallic
structures can come in contact with live equipment or can serve as return current paths.
Aspects: earthing and bonding, voltage propagation, stray current corrosion within the vicinity of d.c.-
electric traction systems.
7 Hazard identification
The top-level hazards and related foreseeable accidents listed in Table 1 were identified systematically
and were used as a basis for the risk assessment. As it is not intended to give a normative definition for
the structure of the hazard log, the hazard log for the reference system as per Clause 6 is given in the
informative Annex A.2.5 and A.3. The results in terms of identified measures are given in Clause 8.
8 Measures
8.1 General
Within this document, the measures identified in the generic risk assessment are interpreted as
requirements to ensure safety within the framework of the applicable standards.
Some measures may only reasonably be applicable to a certain application. This has to be considered
when using the measures listed in this clause as a code of practice.
The following measures are valid for all subsystems of the electric traction system:
– it is anticipated that all applicants have a quality management system established and in place;
– the application of European or International Standards for equipment and dimensioning of equipment
is anticipated for implementation, modification and renewal;
– relevant standards shall be identified and applied. Preferably standards can be taken from the list of
standards as per Annex A;
– adequate design of insulation coordination according to EN 50124 series (insulation coordination),
EN 50123 series (d.c. switchgear), EN 50152 series (a.c. switchgear) and applicable equipment
standards;
– an earthing concept shall be established and implemented;
– adequate design for lightning protection of buildings according to EN 62305 series;
– rules regarding permission for access and permission for work shall be established and applied, e.g.
EN 50110 series, CLC/TR 50488;
– the system shall be kept within the specified ambient conditions, operational limits and the intended
use for all time and under all conditions;
– instructions for operation and maintenance in the O&M manual shall be elaborated and applied;
– personal protective equipment and the safety instructions shall be applied according to the local
regulations and the applicable O&M manuals;
– the standards for electrical safety and local regulations, e.g. qualification of personnel, responsibility
for the safety at work shall be followed; e. g. EN 50110 series, CLC/TR 50488, EN 50122-1;
– appropriate civil structure design (e.g. to contain oil in case of fault, fire protecting wall) according to
the relevant civil standards is anticipated;
– for tunnel sections and underground stations, material with improved properties of low flammability,
low fire spread, low toxicity and low smoke density shall be used if the material could be exposed to
fire;
– 21 – CLC/TS 50562:2011
– as far as reasonably practicable, equipment shall be installed in such a way that adverse effects on
areas for public and passengers by destruction even through severe overload are minimised;
– the storage of inflammable goods in the vicinity of electric traction system has to fulfil the relevant
rules, see also EN 50122-1;
– for systems covered by CLC/TR 50488, the connection of equipment to return circuit/protective earth
during work shall be done consequently for systems with overhead contact lines;
– for systems not covered by CLC/TR 50488, live working can be perm
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