SIST EN 50152-3-1:2017

Railway applications - Fixed installations - Particular requirements for a.c. switchgear - Part 3-1: Measurement, control and protection devices for specific use in a.c. traction systems - Devices

This draft European Standard is applicable to new low voltage devices for measurement, control and protection which are:
-   for indoor or outdoor fixed installations in traction systems, and
-   operated in conjunction with high voltage equipment with an a.c. line voltage and frequency as specified in EN 50163.
NOTE   EN 50163 specifies the a.c. traction systems 15 kV 16,7 Hz and 25 kV 50 Hz.
This draft European Standard will also be applied to measurement, control and protective devices other than low voltage devices and not covered by a specific railway product standard as far as reasonably possible. Requirements of this document prevail.

Bahnanwendungen - Ortsfeste Anlagen – Besondere Anforderungen an Wechselstrom-Schalteinrichtungen - Teil 3-1: Mess-, Steuerungs- und Schutzeinrichtungen für Wechselstrom-Bahnanlagen - Geräte

Dieser Entwurf einer Europäischen Norm gilt für neue Niederspannungs-Mess-, -Steuerungs- und -Schutz-einrichtungen, die
-   für ortsfeste Innenraum- oder Freiluftanlagen in Bahnanlagen ausgelegt sind und
-   zusammen mit einer Hochspannungseinrichtung mit einer Fahrleitungswechselspannung und -frequenz entsprechend der EN 50163 betrieben werden.
ANMERKUNG   EN 50163 benennt für Bahnen die Wechselspannungssysteme 15 kV 16,7 Hz und 25 kV 50 Hz.
Dieser Entwurf einer Europäischen Norm wird auch für Mess-, Steuerungs- und Schutzeinrichtungen gelten, die nicht Niederspannungsgeräte sind und die nicht von einer spezifischen Bahnproduktnorm umfasst sind, soweit dies vernünftigerweise möglich ist. Die Anforderungen dieses Dokumentes haben Vorrang.

Applications ferroviaires - Installations fixes - Exigences particulières pour appareillage à courant alternatif - Partie 3-1: Dispositifs de mesure, de commande et de protection pour usage spécifique dans les systèmes de traction à courant alternatif - Guide d’application

Le présent projet de Norme européenne est applicable aux nouveaux dispositifs basse tension de mesure, de commande et de protection qui sont:
-   destinés aux installations fixes intérieures ou extérieures dans les systèmes de traction, et
-   exploités conjointement avec des équipements haute tension à la tension et à la fréquence d’une ligne à courant alternatif tel que spécifié dans l'EN 50163.
NOTE   L'EN 50163 spécifie les réseaux de traction à courant alternatif de 15 kV 16,7 Hz et 25 kV 50 Hz.
Le présent projet de Norme européenne est également applicable aux dispositifs de mesure, de commande et de protection autres que les dispositifs basse tension non couverts par une norme de produit ferroviaire spécifique dans toute la mesure du possible. Les exigences du présent document prévalent.

Železniške naprave - Stabilne naprave električne vleke - Posebne zahteve za stikalne naprave za izmenični tok - 3-1. del: Merilne, krmilne in zaščitne naprave za izključno uporabo v izmeničnih vlečnih sistemih - Naprave

Ta osnutek evropskega standarda se uporablja za nove nizkonapetostne naprave za merjenje, krmiljenje in zaščito, ki se:
– uporabljajo za notranje ali zunanje nameščene naprave v vlečnih sistemih in
– uporabljajo v povezavi z visokonapetostno opremo z izmenično napetostjo in frekvenco, kot je navedeno v standardu EN 50163.
OPOMBA: Standard EN 50163 določa vlečne sisteme z izmenično napetostjo 15 kV pri 16,7 Hz in 25 kV pri 50 Hz.
Ta osnutek evropskega standarda se uporablja tudi za merilne, krmilne in zaščitne naprave, ki niso nizkonapetostne naprave in niso zajete v posebnem standardu za železniške izdelke, v smiselno mogočem obsegu. Prednost imajo zahteve tega dokumenta.

General Information

• Status: Published
• Public Enquiry End Date: 09-Nov-2015
• Publication Date: 13-Mar-2017
• ICS: 29.130.99 - Other switchgear and controlgear
• ICS: 29.280 - Electric traction equipment
• Technical Committee: ŽEN - Electrical applications for railways
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Mar-2017
• Due Date: 11-May-2017
• Completion Date: 14-Mar-2017
• Ref Project: EN 50152-3-1:2017 - Railway applications - Fixed installations - Particular requirements for a.c. switchgear - Part 3-1: Measurement, control and protection devices for specific use in a.c. traction systems - Devices

Relations

• Revised: SIST EN 50152-3-1:2004 - Railway applications - Fixed installations - Particular requirements for a.c. switchgear -- Part 3-1: Measurement, control and protection devices for specific use in a.c. traction systems - Application guide
• Effective Date: 13-Aug-2014
• Replaces: SIST EN 50152-3-1:2004 - Railway applications - Fixed installations - Particular requirements for a.c. switchgear -- Part 3-1: Measurement, control and protection devices for specific use in a.c. traction systems - Application guide
• Effective Date: 14-Feb-2017

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 50152-3-1:2017
01-april-2017
1DGRPHãþD
SIST EN 50152-3-1:2004
äHOH]QLãNHQDSUDYH6WDELOQHQDSUDYHHOHNWULþQHYOHNH3RVHEQH]DKWHYH]D
VWLNDOQHQDSUDYH]DL]PHQLþQLWRNGHO0HULOQHNUPLOQHLQ]DãþLWQHQDSUDYH]D
L]NOMXþQRXSRUDERYL]PHQLþQLKYOHþQLKVLVWHPLK1DSUDYH
Railway applications - Fixed installations - Particular requirements for a.c. switchgear -
Part 3-1: Measurement, control and protection devices for specific use in a.c. traction
systems - Devices
Bahnanwendungen - Ortsfeste Anlagen – Besondere Anforderungen an Wechselstrom-
Schalteinrichtungen - Teil 3-1: Mess-, Steuerungs- und Schutzeinrichtungen für
Wechselstrom-Bahnanlagen - Geräte
Applications ferroviaires - Installations fixes - Exigences particulières pour appareillage à
courant alternatif - Partie 3-1: Dispositifs de mesure, de commande et de protection pour
usage spécifique dans les systèmes de traction à courant alternatif - Guide d’application
Ta slovenski standard je istoveten z: EN 50152-3-1:2017
ICS:
29.130.99 Druge stikalne in krmilne Other switchgear and
naprave controlgear
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
SIST EN 50152-3-1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50152-3-1:2017

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SIST EN 50152-3-1:2017

EUROPEAN STANDARD EN 50152-3-1

NORME EUROPÉENNE

EUROPÄISCHE NORM
February 2017
ICS 29.130.20; 29.280 Supersedes EN 50152-3-1:2003
English Version
Railway applications - Fixed installations - Particular
requirements for a.c. switchgear - Part 3-1: Measurement,
control and protection devices for specific use in a.c. traction
systems - Devices
Applications ferroviaires - Installations fixes - Exigences Bahnanwendungen - Ortsfeste Anlagen - Besondere
particulières pour appareillage à courant alternatif - Partie Anforderungen an Wechselstrom-Schalteinrichtungen - Teil
3-1 : Dispositifs de mesure, de commande et de protection 3-1: Mess-, Steuerungs- und Schutzeinrichtungen für
pour usage spécifique dans les systèmes de traction à Wechselstrom-Bahnanlagen - Geräte
courant alternatif - Guide d'application
This European Standard was approved by CENELEC on 2016-12-26. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.



European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 50152-3-1:2017 E

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Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Specific requirements from the traction system . 6
5 Requirements on measurement, control and protection devices . 7
5.1 General . 7
5.2 Voltage detection systems . 7
5.3 Devices at supply voltage of a traction system . 7
5.4 Protection devices . 8
Annex A (informative) Application guide - Measurement principles . 9
A.1 Introduction . 9
A.2 Line testing . 9
A.2.1 General . 9
A.2.2 Line testing methods. 9
A.2.3 Line testing procedures . 11
Annex B (informative) Application guide - Control principles . 13
B.1 Introduction . 13
B.2 Closing control . 13
B.2.1 General . 13
B.2.2 Close inhibit . 13
B.2.3 On-command . 14
B.2.4 Auto-reclose . 15
B.3 Opening control . 15
B.3.1 General . 15
B.3.2 Auto-off sequences . 15
B.4 Automated sequences . 18
Bibliography . 19

Figures
Figure A.1 — Example of a feeder related line testing based on voltage criterion . 12

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European foreword
This document (EN 50152-3-1:2017) has been prepared by CLC/SC 9XC “Electric supply and earthing
systems for public transport equipment and ancillary apparatus (Fixed installations)”.
The following dates are fixed:
– latest date by which the EN has to be implemented (dop) 2017-12-26
at national level by publication of an identical
national standard or by endorsement
– latest date by which the national standards conflicting (dow) 2019-12-26
with the EN have to be withdrawn
This document supersedes EN 50152-3-1:2003.
EN 50152-3-1:2017 includes the following significant technical changes with respect to EN 50152-3-1:2003:
It was completely reworked to:
— distinguish between requirements, Clauses 4 and 5, and application guides, annexes;
— include requirements on devices e.g. control and protection relays not included before;
— remove parts already included in other standards, e.g. EN 50633 protection principles.
The EN 50152 series is divided as follows:
— Railway applications — Fixed installations — Particular requirements for alternating current
switchgear — Part 1: Circuit-breakers with nominal voltage above 1 kV;
— Railway applications — Fixed installations — Particular requirements for alternating current
switchgear — Part 2: Disconnectors, earthing switches and switches with nominal voltage above 1 kV;
— Railway applications — Fixed installations — Particular requirements for a.c. switchgear — Part 3-1:
Measurement, control and protection devices for specific use in a.c. traction systems — Devices;
— Railway applications — Fixed installations — Particular requirements for a.c. switchgear — Part 3-2:
Measurement, control and protection devices for specific use in a.c. traction systems — Current
transformers;
— Railway applications — Fixed installations — Particular requirements for a.c. switchgear — Part 3-3:
Measurement, control and protection devices for specific use in a.c. traction systems — Voltage
transformers.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
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Introduction
EN 50152-3-1 is intended for measurement, control and protection devices for specific use in a.c. traction
systems other than current and voltage transformers. These are covered by EN 50152-3-2 and
EN 50152-3-3 respectively.
This standard covers a large variety of different kinds of equipment used in railway fixed installations which
do not have railway specific product standards. It provides clarification on how to select ratings and test
values relevant for operation in fixed installations. This standard needs to be read in conjunction with the
relevant product standard of the equipment concerned.
Annexes A and B are application guides. Annex A deals with railway specific measurement principles and
Annex B provides guidance in the design of control systems for a.c. traction. These application guides
identify characteristics of and parameters for procedures and functions used. Guidance in protection
principles is given in EN 50633.
The clause numbering of this part is different to that used in all other parts of the series. Clause numbering in
the other parts is the same as in the specific referenced product standard
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1 Scope
This European Standard is applicable to new low voltage devices for measurement, control and protection
which are:
— for indoor or outdoor fixed installations in traction systems, and
— operated in conjunction with high voltage equipment with an a.c. line voltage and frequency as specified
in EN 50163.
NOTE EN 50163 specifies the a.c. traction systems 15 kV 16,7 Hz and 25 kV 50 Hz.
This European Standard also applies to measurement, control and protective devices other than low voltage
devices and not covered by a specific railway product standard as far as reasonably possible. Requirements
of this document prevail.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 50121-5, Railway applications — Electromagnetic compatibility — Part 5: Emission and immunity of fixed
power supply installations and apparatus
EN 50124-1, Railway applications - Insulation coordination - Part 1: Basic requirements - Clearances and
creepage distances for all electrical and electronic equipment
EN 50152-2:2012, Railway applications - Fixed installations - Particular requirements for alternating current
switchgear - Part 2: Disconnectors, earthing switches and switches with nominal voltage above 1 kV
EN 50152-3-2:2016, Railway applications - Fixed installations - Particular requirements for a.c. switchgear -
Part 3-2: Measurement, control and protection devices for specific use in a.c. traction systems - Current
transformers
EN 50152-3-3:2016, Railway applications - Fixed installations - Particular requirements for a.c. switchgear -
Part 3-3: Measurement, control and protection devices for specific use in a.c. traction systems - Voltage
transformers
1
EN 50163:2004 , Railway applications — Supply voltages of traction systems
EN 60255-1, Measuring relays and protection equipment - Part 1: Common requirements (IEC 60255-1)
EN 61243-5, Live working - Voltage detectors - Part 5: Voltage detecting systems (VDS) (IEC 61243-5)
EN 61869 (all parts), Instrument transformers (IEC 61869, all parts)
EN 61869-1:2009, Instrument transformers - Part 1: General requirements (IEC 61869-1:2007, modified)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 50152 (all parts) and the following
apply.

1
As impacted by EN 50163:2004/A1:2007, EN 50163:2004/Corrigendum:2010, EN 50163:2004/AC:2013.
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3.1
under-voltage
voltage the value of which is lower than a specified limiting value
[SOURCE: IEC 60050-151:2001, 151-15-29]
3.2
under-voltage off
control function which permits a mechanical switching device to open, with or without time-delay, when the
voltage of the circuit the mechanical switching device is connected to falls below a predetermined value
Note 1 to entry This term is used when a loss of primary voltage is considered.
Note 2 to entry This function will in most cases require any kind of shunt release.
3.3
under-voltage release
shunt release which permits a mechanical switching device to open or close, with or without time-delay,
when the voltage across the terminals of the release falls below a predetermined value
[SOURCE: IEC 60050-441:2000, 441-16-42]
Note 1 to entry This term is used when a loss of an auxiliary voltage is considered
3.4
under-voltage trip
protection function which permits a mechanical switching device to open, with or without time-delay, when
the voltage of the circuit the mechanical switching device falls below a predetermined value
Note 1 to entry This term is used when a loss of primary voltage is considered.
Note 2 to entry This function will in most cases require any kind of shunt release.
4 Specific requirements from the traction system
Traction systems due to e.g. their load, voltage and earthing conditions require thorough analysis when
defining operational principles and requirements for equipment.
The design of measurement, control and protection circuits, their devices and algorithms shall consider any
effect arising from:
— fast fluctuation of traction power demand;
— moving tractions units, providing scenarios with traction currents higher than failure currents;
— the return current system, especially the track, effectively connected to earth;
— fast fluctuation of operating voltages between U and U , with U and U as specified in
min2 max2 min2 max2
EN 50163;
— high number of switching operations e.g. caused by a high number of short circuits in the contact line
systems;
— in 16,7 Hz traction systems the duration of a period of 60 ms in respect to magnetisation, saturation and
switching times;
— in auto-transformer systems, a phase shift of 180° resulting in an maximum operating voltage of 2 *
U but only between phases.
max2
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NOTE 1 The return circuit in a.c. traction systems is effectively earthed. Unlike utility networks a displacement of the
star point during earth faults resulting in an increase of phase voltages by factor √3 cannot happen.
NOTE 2 Equipment in a 25 kV traction system is subject to a maximum permanent operating voltage phase to earth
of 27,5 kV = Umax1. Equipment in a 3 phase utility network with a highest system voltage Um = 36 kV has an average
continuous voltage phase to earth during 99 % of its life of 33/√3 kV = 19,1 kV.
If the above values are compared, it becomes clear that the dielectric stress of equipment in traction power supply is
significantly higher and therefore the test voltages e.g. during partial discharge testing have assigned higher values in
this European Standard.
5 Requirements on measurement, control and protection devices
5.1 General
Measurement, control and protection devices shall be designed, manufactured and tested to their specific
product standards. Requirements of railway standards prevail and shall be applied as far as reasonably
possible. This especially concerns EN 50124-1 for insulation coordination and EN 50121-5 for
electromagnetic compatibility.
5.2 Voltage detection systems
Capacitive voltage detection systems shall comply with EN 61243-5 except for the following requirements:
— voltage absence indication shall be below 50 % of Umin2,
— voltage presence indication shall be above 90 % of Umin2 and
— the capacitive voltage detection system shall properly work also up to Umax2.
NOTE 1 The thresholds for voltage absence and presence indication are adapted considering the fact that voltages
are between contact line and running rail on ground potential and also the tolerances of supply voltages of traction
systems.
When selecting voltage detectors manufactured according to EN 61243-1 it may be preferential to use
thresholds for voltage absence and presence indication as specified before.
NOTE 2 This portable equipment is only temporarily connected to a supply voltage of the traction system.
NOTE 3 There are national standards available in some countries specifying thresholds for voltage absence and
presence indication.
5.3 Devices at supply voltage of a traction system
Devices not covered by a railway specific product standard and being connected to a circuit at supply voltage
of a traction system shall comply with the test voltages including partial discharge level as specified in
EN 50152-3-3 for this supply voltage. If these devices are connected to provide isolation of feeding systems
the test voltages shall be taken for “across the isolating distance” from EN 50152-2:2012, Table 1 e.g. when
connected parallel to a disconnector.
Other requirements of EN 50152-3-2 or EN 50152-3-3 or for sensors as given in the EN 61869 series shall
apply as far as reasonably possible and shall be agreed upon between supplier and infrastructure manager.
Devices containing electronic parts shall be subject to a function test in the intended operational circuit and
under worst case conditions e.g. in its installation position next to a circuit breaker during a short circuit
breaking test.
Dielectric type tests shall be applied as specified in EN 61869-1:2009, 7.2.3 with test values as specified in
EN 50152-3-3:2016, 7.1. Dielectric routine tests shall be applied as specified in EN 61869-1:2009, 7.3.1 to
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7.3.4 with test values as specified in EN 50152-3-3:2016, 7.1 and 7.3. Other tests and their test requirements
shall be agreed upon between purchaser and supplier prior to the order.
5.4 Protection devices
Protection devices used in railway applications shall comply with the relevant product standards, particularly
EN 60255-1. They shall also comply with the electromagnetic compatibility requirements given in
EN 50121-5.
Any protection device shall be specified based on a consideration of the specific requirements from the
traction system as given in Clause 4.
Protection devices for contact line protection shall include the following protection functions:
— distance protection with a minimum of two stages and the possibility to use directional settings;
— di/dt or du/dt protection;
— de-icing protection, when specified e.g. by the system designer or infrastructure manager;
— the possibility for blocking or delaying between the functions.
NOTE 1 This kind of protection device will typically use specially adapted algorithms and will therefore be different to
devices intended for utility use.
NOTE 2 EN 50633 provides an application guide on protections systems including back scenarios.
Protection devices for 16,7 Hz contact line protection shall include the following protection functions in
addition:
— instantaneous overcurrent protection;
— fast acting trip output.
NOTE 3 Instantaneous overcurrent protection in combination with the fast acting trip output are intended to support
fault clearance in the first half of the period. 16,7 Hz circuit breakers are typically equipped with a fast tripping device and
total time until opening of the breaker is in the range of 20 ms to 25 ms.
NOTE 4 Algorithms for 16,7 Hz contact line protection devices are in many cases different to those of 50 Hz devices.
This is due to the aim to achieve similar response times out of a shorter fraction of the period. Hardware modifications
are also likely to be required.
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Annex A
(informative)

Application guide - Measurement principles
A.1 Introduction
This application guide provides guidance in measurement principles typical to traction systems.
NOTE Many other principles are well known from public power supply systems and are not repeated in this annex.
Line testing has been classified as a measurement principle. Nevertheless it normally only provides a
comparison to a threshold and not a measurement value.
A.2 Line testing
A.2.1 General
Overhead contact lines are exposed to a significantly higher number of short circuits compared to other
overhead lines. This is due the reduced height of installation above ground and operation together with fast
moving pantographs.
Any short circuit provides extra stress to the contact line which is sensitive to over-temperatures. This
sensitivity is influenced by many parameters including cross-sections and tensile force. Based on this data
and under consideration of traction load, short-circuit current level and protection scheme the withstand-
ability of the contact line against e.g. repeated short circuits may be determined.
NOTE 1 A typical value derived from operational experience is 1 short circuit each km of contact line per annum.
NOTE 2 Most sensitive to loss of tensile strength are droppers between messenger and contact wire.
The recommendation is to consider measures reducing the number of short circuits for a contact line. One
possibility is to close line circuit breakers only after the ‘short circuit free’ condition of the contact line has
been verified. Experience has shown that line testing provides a substantial benefit with short circuit current
levels from 20 kA and higher.
NOTE 3 16,7 Hz railways with short circuit current levels of up to 40 kA typically use line testing whereas 50 Hz
railways with short-circuit current levels of up to 16 kA typically do not.
NOTE 4 Saturation of current transformers sometimes leads to a delay in tripping of the circuit breaker after switching
on to a short circuit. Thermal stress to the contact line is unnecessarily increased in these cases. The current transformer
design needs to consider this effect.
All line test principles have in common that the contact line is energised with a voltage in the range of the
supply voltage for a predetermined time. The testing source provides a short circuit impedance limiting the
failure current in case of a short circuit to a few percent of the rated current. Detection method and related
parameters are fixed by the system designers / infrastructure managers for the system.
A.2.2 Line testing methods
A.2.2.1 Line testing based on voltage criterion
This method uses a test resistor limiting the fault current to values below 10 A. The resistor is connected to
the feeder cable of the contact line under test and switched on to the feeding system e.g. by a switch-
disconnector. The voltage at the contact line is measured and provides the criterion for switching on.
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NOTE 1 Typical resistance values are 3,3 kΩ to 5 kΩ leading to maximum test currents of 5,4 A to 3,6 A in 16,7 Hz
railways. These resistors are typically indoor mounted, special precautions need to be established to prevent overheating
of the room due to the losses during testing.
A value in the range of 50 % of the nominal supply voltage is typically considered as short circuit free. A
voltage transformer on the contact line side is required for this measurement. The result of the voltage
measurement is increased by parallel overhead and overhead contact lines already energised and
decreased by loads not automatically switched off e.g. points heating transformers or train heating.
NOTE 2 It is normal practice in some countries to leave the train heating energised also when parked in depot or
yard.
If this method is used the following should be specified:
— resistance of the test resistor;
— voltage value for short circuit free detection;
— test cycle, including individual on and idle times;
— number of cycles with negative result prior to a lock-out;
Temperature monitoring may be used to utilize the thermal capacity of the test resistor.
A.2.2.2 Line testing based on current criterion
A.2.2.2.1 By means of resistors
As in A.2.2.1 this method uses a resistor to limit the short circuit current. The testing current is measured
either by a separate current transformer in the testing circuit or by the current transformer of the line feeder
circuit.
NOTE 1 Typical resistance values are 400 Ω to 550 Ω leading to maximum test currents of 45 A to 33 A in 16,7 Hz
railways. These resistors are typically outdoor mounted due to the big losses during testing.
NOTE 2 Possible saturation needs to be considered when the current transformer of the line feeder circuit is used.
A value in the range of 20 to 30 A is typically considered as short circuit free. This method is more robust to
loads not automatically switched off due to the lower resistance value used compared to line testing based
on voltage criterion.
If this method is used the following should be specified:
— resistance of the test resistor;
— current value for short circuit free;
— test cycle, including individual on and idle times;
— number of cycles with negative result prior to a lock-out.
Temperature monitoring may be used to utilize the thermal capacity of the test resistor.
A.2.2.2.2 By means of electronic devices
Modern high voltage power electronic devices are combined into a larger unit including internal control and
auxiliary power supply. These units can be operated directly at traction line voltage in the same way as line
testing utilizing resistors. The current is limited by internal control. Due to their limited thermal capacity these
units are operating with single pulses only. The line test results may be achieved by evaluation of the current
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over time integral, also the voltage across the open testing device may be considered. The results are
typically sent to the control system via a fibre optic cable.
NOTE These devices are typically used in conjunction with feeder related line testing procedures due to the
compact design.
A.2.2.3 Other line testing methods
Line testing methods using test resistors to limit the test current produces high losses during line fault
conditions. Other line testing methods may therefore also be applied provided they support reliable operation
and allow an acceptable level of discrimination between normal and short-circuit conditions.
NOTE Various methods using inductances, capacitances or special transformers have already been investigated as
an alternative. None of t
...