EN 50328:2003

SLOVENSKI SIST EN 50328:2004
STANDARD
september 2004
Železniške naprave – Stabilne naprave električne vleke – Elektronski
močnostni pretvorniki za napajalne postaje
Railway applications - Fixed installations - Electronic power converters for
substations
ICS 29.200; 29.280 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 50328
NORME EUROPÉENNE
EUROPÄISCHE NORM March 2003
ICS 29.200; 29.280 Partly supersedes EN 60146-1-1:1993

English version
Railway applications -
Fixed installations -
Electronic power converters for substations

Applications ferroviaires -  Bahnanwendungen -
Installations fixes - Ortsfeste Anlagen -
Convertisseurs électroniques Leistungselektronische Stromrichter
de puissance pour sous-stations für Unterwerke

This European Standard was approved by CENELEC on 2002-09-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

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

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50328:2003 E
Foreword
This European Standard 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.
The text of the draft was submitted to the formal vote and was approved by CENELEC as
EN 50328 on 2002-09-01.
This European Standard supersedes EN 60146-1-1:1993 for the specific products concerning
railway applications as mentioned in the scope of this standard.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2003-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-09-01

Annexes designated "informative" are given for information only.
In this standard, Annexes A, B and C are informative.
__________
- 3 - EN 50328:2003
Contents
Introduction .5
1 General.6
1.1 Scope.6
1.2 Normative references.6
1.3 Classification of traction supply power converters and valve.7
1.4 List of principal letter symbols .8
1.5 Definitions .9
2 Service conditions.20
2.1 Code of identification of cooling method.20
2.2 Environmental conditions .21
2.3 Electrical service conditions .23
3 Converter equipment and assemblies .25
3.1 Electrical connections.25
3.2 Calculation factors.26
3.3 Losses and efficiency.27
3.4 Power factor.27
3.5 Direct voltage harmonic content.28
3.6 Electromagnetic compatibility (EMC).28
3.7 Rated values for converters .28
3.8 Mechanical characteristics .31
3.9 Marking .32
4 Tests.33
4.1 General .33
4.2 Test specifications.34
Annex A (informative) Information required .40
A.1 General .40
A.2 Diode rectifiers .40
A.3 Controlled converters and inverters.41
A.4 Frequency converters (direct and d.c. link converters) .43
Annex B (informative) Determination of the current capability through calculation
of the virtual junction temperature.45
B.1 General .45
B.2 Approximation of the shape of power pulses applied to the semiconductor device .45
B.3 The superposition method for calculation of temperature.46
B.4 Calculation of virtual junction temperature for continuous load.46
Annex C (informative) Index of definitions .50
Bibliography .53

Figure 1 - Illustration of angles .13
Figure 2 - Voltage drop.17
Figure 3 - A.C. voltage waveform .24
Figure B.1 - Approximation of the shape of power pulses .46
Figure B.2 - Calculation of the virtual junction temperature for continuous load .47
Figure B.3 - Calculation of the virtual junction temperature for cyclic load.48

Table 1 - Immunity levels .19
Table 2 - Letter symbols for cooling mediums and heat transfer agents.20
Table 3 - Letter symbols for methods of circulation .20
Table 4 - Connections and calculation factors for line commutated converters .26
Table 5 - Standardized duty classes.30
Table 6 - Semiconductor device failure conditions.31
Table 7 - Summary of tests .34
Table 8 - Insulation levels for a.c./d.c. converters.36
Table B.1 - Examples for typical applications .49

- 5 - EN 50328:2003
Introduction
Semiconductor converters for traction power supply differ from other converters for industrial
use due to special electrical service conditions and due to the large range of load variation and
the peculiar characteristics of the load.
For these reasons EN 60146-1-1 does not fully cover the requirements of railway applications
and the decision was taken to have a specific European standard for this use.
Converter transformers for fixed installations of railway applications are covered by EN 50329.
Harmonization of the rated values and tests of the whole converter group are covered by
EN 50327.
1 General
1.1 Scope
This European Standard specifies the requirements for the performance of all fixed installations
electronic power converters, using controllable and/or non-controllable electronic valves,
intended for traction power supply.
The devices can be controlled by means of current, voltage or light. Non-bistable devices are
assumed to be operated in the switched mode.
This European Standard applies to fixed installations of following electric traction systems:
− railways,
− guided mass transport systems such as: tramways, light rail systems, elevated and
underground railways, mountain railways, trolleybusses.
This European Standard does not apply to
− cranes, transportable platforms and similar transportation equipment on rails,
− suspended cable cars,
− funicular railways.
This European Standard applies to diode rectifiers, controlled rectifiers, inverters and frequency
converters.
The equipment covered in this European Standard is the converter itself.
1.2 Normative references
This European Standard incorporates by dated or undated reference provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed below. For dated references, subsequent amendments or revisions of
any of these publications apply to this European Standard only when incorporated into it by
amendment or revision. For undated references, the latest edition of the publication referred to
applies (including amendments).
EN 50121 Series 2000 Railway applications - Electromagnetic compatibility
EN 50123-7-1 2003 Railway applications - Fixed installations - D.C. switchgear
Part 7-1: Measurement, control and protection devices for specific
use in d.c. traction systems - Application guide
EN 50124-1 2001 Railway applications - Insulation coordination
Part 1: Basic requirements - Clearances and creepage distances
for all electrical and electronic equipment
EN 50163 1995 Railway applications - Supply voltages of traction systems

EN 50327 2003 Railway applications - Fixed installations - Harmonisation of the
rated values for converter groups and tests on converter groups
EN 50329 2003 Railway applications - Fixed installations - Traction transformers
EN 60529 1991 Degrees of protection provided by enclosures (IP Code)
(IEC 60529:1989)
EN 60721 Series Classification of environmental conditions (IEC 60721 series)

- 7 - EN 50328:2003
EN 61000-2-4 1994 Electromagnetic compatibility (EMC) - Part 2-4: Environment -
Compatibility levels in industrial plants for low-frequency
conducted disturbances
(IEC 61000-2-4:1994 + corr. August 1994)
IEC 60050-551 1998 International Electrotechnical Vocabulary
Chapter 551: Power Electronics
IEC 60050-811 1991 International Electrotechnical Vocabulary
Chapter 811: Electric traction
IEC 60146-1-2 1991 Semiconductor converters - General requirements and line
commutated converters - Part 1-2: Application guide

1)
IEC 61000-2-12 Electromagnetic compatibility (EMC) - Part 2-12: Environment -
Compatibility levels for low-frequency conducted disturbances and
signalling in public medium voltage power supply systems
1.3 Classification of traction supply power converters and valve
1.3.1 Types of traction supply power converters

A) a.c. to d.c. conversion:
1) diode rectifier;
2) controlled rectifier.
B) d.c. to a.c. conversion:
1) inverter.
C) a.c. to a.c. conversion:
1) direct frequency converter;
2) d.c. link frequency converter:
i) supply side;
ii) traction side.
1.3.2 Purpose of conversion
A converter changes or controls one or more characteristics such as
1) frequency (including zero frequency),
2) voltage,
3) number of phases,
4) flow of reactive power,
5) quality of load power.
1)
To be published.
1.3.3 Classification of semiconductor valves
Semiconductor valves can be turned off either by commutation implying that the current of the
valve is transferred to another valve or by quenching if the current of the valve falls to zero.
Valves used in traction supply power converters can be divided into the following categories:
1) non controllable valve with a conductive forward and a blocking reverse characteristic
(diode);
2) valve with a controllable forward and a blocking reverse characteristic (e.g. reverse
blocking thyristor);
3) valve with a controllable forward and a conductive reverse characteristic (e.g. reverse
conducting thyristor);
4) valve with a controllable forward and / or reverse characteristic which can be turned on
and/or off via a signal applied to the gate (e.g. gate turn-off thyristor, insulated gate bipolar
transistor);
5) valve with controllable forward and reverse characteristic (e.g. bi-directional thyristors).
1.4 List of principal letter symbols
d inductive direct voltage drop due to converter transformer referred to U
xtB di
e inductive component of the relative short-circuit voltage of the converter transformer
xB
corresponding to the basic current on the supply side of the transformer
f rated frequency
N
g number of sets of commutating groups between which I is divided
Bd
h order of harmonic
I basic direct current
Bd
I basic service current on the supply side of a converter
BV
I direct current (any defined value)
d
I rated current on the traction side of a frequency converter
Nt
K coupling factor
p pulse number
P active power
q commutation number
s number of series connected commutating groups
u angle of overlap (commutation angle)
U power frequency withstand voltage
a
U total inductive direct voltage drop at basic direct current
Bdx
U direct voltage (any defined value)
d
U conventional no load direct voltage
d0
U value of U with trigger delay angle α
d0α d0
U real no-load direct voltage
d00
U ideal no-load direct voltage
di
U controlled ideal no-load direct voltage
diα
U nominal voltage
n
U rated direct voltage
Nd
U Impulse voltage
Ni
U rated insulation voltage
Nm
U rated a.c.voltage on the traction side of a frequency converter
Nt
- 9 - EN 50328:2003
U rated a.c. voltage on the supply side of a converter
NV
U no-load phase to phase voltage
V0
α trigger delay angle
α inherent delay angle
p
β trigger advance angle
γ extinction angle
δ number of commutating groups commutating simultaneously per primary
λ total power factor
ν deformation factor
ϕ1 displacement angle for the fundamental component of I
BV
1.5 Definitions
For the purpose of this European Standard, the following definitions apply. In this standard, IEV
definitions are used wherever possible, particularly those in IEC 60050-551.
The policy adopted is as follows:
1) when a suitable IEV definition exists, the title and reference are given without repeating the
text;
2) when an existing IEV definition needs amplification or additional information, the title, the
reference and the additional text are given;
3) when no IEV definition exists, the title and the text are given;
4) the definitions appear under
A) for general terms (1.5.1 to 1.5.28),
B) for service conditions (1.5.29 to 1.5.30),
C) for definitions concerning compatibility (1.5.31 to 1.5.33).
An alphabetical index is given in Annex C.
A) General terms
1.5.1
semiconductor device
device whose essential characteristics are due to the flow of charge carriers within a
semiconductor
1.5.2
Combination of semiconductor devices

1.5.2.1
(valve device) stack (IEV 551-14-12)

1.5.2.2
(valve device) assembly (IEV 551-14-13)

1.5.2.3
electronic power converter
an operative unit for power conversion comprising one or more assemblies of semiconductor
devices (IEV 551-12-01, modified)

1.5.2.4
trigger equipment (gating equipment)
equipment which provides suitable trigger pulses from a control signal for controllable valve
devices in a converter or power switch including timing or phase shifting circuits, pulse
generating circuits and usually power supply circuits

1.5.2.5
system control equipment
equipment associated with a converter equipment or system which performs automatic
adjustment of the output characteristics as a function of a controlled quantity

1.5.3
Converter circuit elements
1.5.3.1
(valve) arm (IEV 551-15-01)
1.5.3.2
principal arm IEV 551-15-02)
1.5.4
converter connection (IEV 551-15-10)

1.5.4.1
basic converter connection (IEV 551-15-11)

1.5.4.2
single-way connection (of a converter) (IEV 551-15-12)

1.5.4.3
double-way connection (of a converter) (IEV 551-15-13)

1.5.4.4
uniform connection (IEV 551-15-15)

1.5.4.5
non-uniform connection (IEV 551-15-18)

1.5.4.6
series connection
a connection in which two or more converters are connected in such a way that their voltages
add
1.5.4.7
boost and buck connection
a series connection in which the converters are controlled independently (IEV 551-15-21,
modified)
1.5.4.8
parallel connection
a connection in which two or more converters are connected in such a way that their currents
add
- 11 - EN 50328:2003
1.5.5
Controllability of converter arms

1.5.5.1
controllable arm
converter arm including controllable semiconductor element(s) as valve device(s)

1.5.5.2
non-controllable arm
converter arm including no controllable semiconductor element(s) as valve device(s)

1.5.6
quadrants of operation (on d.c. side)
each quadrant of the voltage current plane is defined by the d.c. voltage polarity and the current
direction
1.5.6.1
one quadrant converter (IEV 551-12-34)

1.5.6.2
two quadrant (single) converter (IEV 551-12-35)

1.5.6.3
four quadrant (double) converter (IEV 551-12-36)

1.5.6.4
reversible converter (IEV 551-12-37)

1.5.6.4.1
single converter (IEV 551-12-38)

1.5.6.4.2
double converter (IEV 551-12-39)

1.5.6.4.3
converter section of a double converter (IEV 551-12-40)

1.5.7
Commutation and quenching
1.5.7.1
commutation
transfer of current from one conducting arm to the next to conduct in sequence, without
interruption of the d.c. current. During a finite interval of time both arms are conducting
simultaneously (IEV 551-16-01, modified)

1.5.7.2
quenching (IEV 551-16-19)
1.5.8
Type of commutation
1.5.8.1
direct commutation (IEV 551-16-09)

1.5.8.2
indirect commutation (IEV 551-16-10)

1.5.8 3
external commutation (IEV 551-16-11)

1.5.8.3.1
line commutation (IEV 551-16-12)

1.5.8.3.2
load commutation (IEV 551-16-13)

1.5.8.4
self commutation (IEV 551-16-15)

1.5.9
commutation circuit (IEV 551-16-03)

1.5.9.1
commutating voltage (IEV 551-16-02)

1.5.9.2
commutation inductance
total inductance included in the commutation circuit, in series with the commutating voltage
(IEV 551-16-07, modified)
NOTE For line or machine commutated converters the commutation reactance is the impedance of the
commutation inductance at the fundamental frequency.

1.5.9.3
angle of overlap u
the duration of the commutation interval between a pair of principal arms, expressed in angular
measure, where the two arms carry current (IEV 551-16-05, modified)

1.5.9.4
commutation notch
a periodic voltage transient that can appear in the a.c. voltage of a line or machine-commutated
converter due to commutation (IEV 551-16-06, modified)

1.5.9.5
commutation repetetive transient
voltage oscillation associated with the commutation notch

1.5.9.6
commutating group (IEV 551-16-08)

- 13 - EN 50328:2003
1.5.9.7
commutation number q
the number of commutations from one principal arm to another, occurring during one period of
the alternating voltage in each commutating group (IEV 551-17-03, modified)

1.5.9.8
pulse number p
the number of non-simultaneous symmetrical direct or indirect commutations from one principal
arm to another, during one period of the alternating voltage (IEV 551-17-01, modified)

1.5.10
trigger delay angle α
the time expressed in angular measure by which the trigger pulse is delayed with respect to the
reference instant (see Figure 1).

For line, machine or load commutated converters the reference instant is the zero crossing
instant of the commutating voltage.

For a.c. controllers it is the zero crossing instant of the supply voltage.
For a.c. controllers with inductive load, the trigger delay angle is the sum of the phase shift and
the current delay angle
(IEV 551-16-33, modified)
Figure 1 - Illustration of angles

1.5.11
trigger advance angle ß (IEV 551-16-34)
(see Figure 1)
1.5.12
inherent delay angle α
p
the delay angle which occurs in some converter connections under certain operating conditions
even if no phase control is applied (IEV 551-16-35, modified)

1.5.13
extinction angle γ
the time, expressed in angular measure, between the moment when the current of the arm falls
to zero and the moment when the arm is required to withstand steeply rising off-state voltage

1.5.14
rated value
numerical value for the electrical, thermal, mechanical and environmental rating assigned to the
quantities which define the operation of a converter group in the conditions specified in
accordance with this European Standard and on which the supplier’s guarantees and tests are
based
1.5.15
rated frequency f
N
the frequency on either side of the converter for the conversion of which the converter group is
designed to operate
1.5.16
nominal voltage U
n
voltage by which a converter is designated

NOTE The standardized values of nominal voltages are given in EN 50163.

1.5.17
rated insulation voltage U
Nm
an r.m.s. withstand voltage value assigned by the manufacturer to the equipment or a part of it,
characterizing the specified permanent withstand capability of its insulation

NOTE Standardized values of rated insulation voltages are given in EN 50124-1.

1.5.18
Rated voltage(s) on the a.c. side(s) of a converter

1.5.18.1
rated a.c. voltage on the supply side of a converter U
NV
the r.m.s. value of the no-load voltage between vectorially consecutive commutating phase
terminals of a commutating group

1.5.18.2
rated a.c. voltage on the traction side of a converter U
Nt
the r.m.s. value of the no-load voltage on the traction side of a frequency converter

- 15 - EN 50328:2003
1.5.19
rated direct voltage U
Nd
the specified value of the direct voltage between the d.c. terminals of the converter assembly at
basic direct current. This value is the mean value of the direct voltage

NOTE 1 A converter may have more than one rated voltage or a rated direct voltage range.

NOTE 2 The rated direct voltage of a converter depends on the characteristics of the transformer and a
guaranteed value of rated direct voltage is valid only together with the transformer (see EN 50327).

1.5.20
Current(s) on the a.c. side(s) of a converter

1.5.20.1
basic service current on the supply side of a converter I
BV
the r.m.s. value of the a.c. current, containing all harmonics, on the supply side of a converter
at basic current on the d.c. side

NOTE For polyphase equipment, this value is computed from the basic direct current on the basis of rectangular
shaped currents, 120 ° conducting, of the converter elements. For single phase equipment, the basis of calculation
shall be specified.
1.5.20.2
rated current on the traction side of a frequency converter I
Nt
the r.m.s. value of the a.c. current on the traction side of a frequency converter under rated
conditions
1.5.21
basic direct current I
Bd
mean value of the direct current for specified load and service conditions

NOTE Together with a duty class I is considered as the 1,0 p.u. value, to which other values of I are compared
Bd d
1.5.22
Load capabilities
1.5.22.1
duty class
tabled representation of current capability and test values for standard design converters in
terms of current values and duration selected to represent a characteristic group of practical
applications. The current values are expressed in per unit of the basic direct current I
Bd
1.5.22.2
load cycle
representation of the conventional current demand to a special design converter showing the
repetitive variation of the load within a specified time period. The current values are expressed
in A or in per unit of I
Bd
1.5.23
d.c. power
the product of the nominal d.c. voltage U and the basic direct current I
n Bd
1.5.24
power efficiency
the ratio of the output power to the input power of the converter

1.5.25
Factors on the a.c. side
1.5.25.1
total power factor λ
active power
λ =
apparent power
1.5.25.2
power factor of the fundamental wave or displacement factor cos ϕ
active power of the fundamental wave
cos ϕ =
apparent power of the fundamental wave

1.5.25.3
deformation factor ν
λ
ν =
cos ϕ
1.5.26
Definitions used in connection with d.c. systems

1.5.26.1
ideal no-load direct voltage U
di
the theoretical no-load mean direct voltage of a converter, assuming no reduction by phase
control, no voltage drop in the assemblies and no voltage rise at small loads
It is obtained from the voltage between two commutating phases U , the commutation number
v0
q and the number of series-connected commutating groups s, between terminals on d.c. side,
by the formula (IEV 551-17-15, modified):
2 q × s
U = U × ×
di v0
2 π
NOTE The formula is not valid for voltage multiplying circuits.

1.5.26.2
controlled ideal no-load direct voltage U
diα
the theoretical no-load mean direct voltage of a converter, when the direct voltage is reduced
by phase control, assuming no voltage drop in the assemblies and no voltage rise at small
loads as obtained by the formulae below (IEV 551-17-16, modified)

1) Uniform connection
a) If the direct current is continuous over the entire control range:
U = U × cosα
diα di
b) If the converter load is purely resistive:
π π
for 0 ≤ α ≤ − : U = U × cosα
diα di
2 p
π π π π 1− sin(α − π / p)
for − ≤ α ≤ + : U = U ×
diα di
2 p 2 p 2 sin(π / p)
2) Non-uniform connections
U = 0,5 × U × (1+ cosα)
diα di
- 17 - EN 50328:2003
1.5.26.3
conventional no-load direct voltage U
d0
the mean value of the direct voltage which would be obtained by extrapolating the direct
voltage/current characteristic for continuous direct current back to zero current
(IEV 551-17-17, modified)
NOTE U is equal to the sum of U and the no-load voltage drop in the assembly.
di d0
1.5.26.4
controlled conventional no-load direct voltage U
d0α
the conventional no-load mean direct voltage obtained when extrapolating the direct voltage/
current characteristic, corresponding to a delay angle a, back to zero current
(IEV 551-17-18, modifed)
1.5.26.5
real no-load direct voltage U
d00
the actual mean direct voltage at zero direct current (IEV 551-17-19, modified)

1.5.26.6
transition current
the mean direct current of a converter connection when the direct current of the commutating
groups becomes intermittent when decreasing the current (IEV 551-17-20, modified)
NOTE At the transition current value, the voltage/current characteristic bends. Transition current can be
obtained, for example in the case of back e.m.f. load because the inductance of the d.c. circuit cannot maintain
direct current over the entire period or in case of interphase transformer connection, because the direct current
decreases below the critical value where the interphase transformer becomes ineffective.

Figure 2 - Voltage drop
1.5.27
direct voltage drop
the difference between the conventional no-load direct voltage and the direct voltage at basic
direct current, at the same current delay angle, excluding the correction effect of stabilizing
means if any (IEV 551-17-21, modified)

NOTE The nature of the d.c. circuit (for example capacitors, back e.m.f. load) can affect the voltage drop
significantly. Where this is the case, special consideration is required.

1.5.28
Definitions related to virtual junction temperature

1.5.28.1
thermal resistance R
th
the quotient of the temperature difference between two specified points or regions and the heat
flow between these two points or regions under conditions of thermal equilibrium

NOTE For most cases, the heat flow can be assumed to be equal to the power dissipation.

1.5.28.2
transient thermal impedance Z
th
the quotient of the variation of the temperature difference, reached at the end of a time interval
between the virtual junction temperature and the temperature at a specified external reference
point and the step function change of power dissipation at the beginning of the same time
interval causing the change of temperature

NOTE The transient thermal impedance is given in a characteristic curve as a function of the time interval.

1.5.28.3
virtual junction temperature Θ
j
a calculated temperature within the semiconductor material which is based on a simplified
representation of the thermal and electrical behaviour of a semiconductor device

B) Definitions of service conditions (temperature and ambient conditions)

1.5.29
Definitions related to cooling

1.5.29.1
cooling medium
a liquid (for example water) or gas (for example air) which removes the heat from the
equipment
1.5.29.2
heat transfer agent
a liquid (for example water) or gas (for example air) within the equipment to transfer the heat
from its source to a heat exchanger from where the heat is removed by the cooling medium

1.5.29.3
direct cooling
a method of cooling by which the cooling medium is in direct contact with the parts of the
equipment to be cooled, i.e. no heat transfer agent is used

1.5.29.4
indirect cooling
a method of cooling in which a heat transfer agent is used to transfer heat from the part to be
cooled to the cooling medium
- 19 - EN 50328:2003
1.5.29.5
Circulation of the cooling medium or of the heat transfer agent

1.5.29.5.1
natural circulation (convection)
a method of circulating the cooling medium or heat transfer agent which uses the change of
volumetric mass (density) with temperature

1.5.29.5.2
forced circulation (forced cooling)
a method of circulating the cooling medium or heat transfer agent by means of blower(s), fan(s)
or pump(s)
1.5.29.5.3
mixed circulation
a method of circulating the cooling medium or heat transfer agent, which uses alternatively
natural and forced circulation

1.5.30
equilibrium temperature
the steady-state temperature reached by a component of a converter under specified conditions
of load and cooling
NOTE The steady-state temperatures are in general different for different components. The times necessary to
establish steady-state are also different and proportional to the thermal time constants.

C) Definitions concerning compatibility

1.5.31
electrical disturbance
any variation of an electrical quantity, beyond specified limits, which can be the cause of a loss
of performance or an interruption of service or damage

1.5.32
immunity level of a converter
specified value of an electrical disturbance below which a converter is designed to meet the
required performances or continue operation or avoid damage

Table 1 – Immunity levels
Immunity level Symbol Possible consequence if exceeded
Redundancy R No loss of performance
Functional F Loss of performance
Tripping+ T Interruption of service due to protective devices
Damage D Interruption of service due to a damage (fuses excepted)

1.5.33
(total) harmonic distortion (IEV 551-17-06)

2 Service conditions
2.1 Code of identification of cooling method
NOTE  In most cases, the identification code for the cooling method is the same as that in use for transformers.

2.1.1 Letter symbols to be used
2.1.1.1 Cooling medium or heat transfer agent
Table 2 – Letter symbols for cooling mediums and heat transfer agents
Cooling medium or heat transfer agent Symbol
Mineral oil O
Dielectric liquid (other than mineral oil) L
Gas G
Water W
Air A
Fluid used for two-phase cooling P

2.1.1.2 Method of circulation
Table 3 - Letter symbols for methods of circulation
Method of circulation Symbol
Natural (convection) N
Forced, moving device not incorporated E
Forced, moving device incorporated F
Vapour cooling V
2.1.2 Arrangement of letter symbols
2.1.2.1 Direct cooling
The first letter indicates the cooling medium (2.1.1.1), the second the circulation method
(2.1.1.2).
Example: AN: air cooled, natural circulation (convection).
2.1.2.2 Indirect cooling
The code includes four symbols.
The first two letters indicate
a) the heat transfer agent (2.1.1.1),
b) the circulation method of the heat transfer agent (2.1.1.2).

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The last two letters indicate
a) the cooling medium (2.1.1.1),
b) the circulation method of the cooling medium (2.1.1.2).
Example: OFAF: converter with forced circulated oil (pump) as heat transfer agent
and forced circulated (fan) air as cooling medium.
2.1.2.3 Mixed cooling method
For both cases, direct cooling or indirect cooling, if the circulation is alternatively natural or
forced, two groups of symbols, separated by a stroke, shall indicate both possible methods of
circulation as used, the first group corresponding with the lower heat flow or the lower ambient
air temperature.
Therefore, the complete code shall include
a) for direct cooling: two groups of letters separated by a stroke,
Example 1: AN/AF: converter with natural direct air cooling and possibilities for
forced direct air cooling
b) for indirect cooling: two groups of letter symbols separated by a stroke.
Example 2: OFAN/OFAF: converter with forced circulated oil as heat transfer agent
and natural air as cooling medium with possibilities for
forced air as cooling medium
2.2 Environmental conditions
2.2.1 Ambient air circulation
Equipment installed in a room shall be connected to the (unlimited) supply of cooling medium or
if the cooling air is taken from the ambient in the room, provision shall be made to extract the
heat from the room, which then can be considered as an intermediate heat-exchanger between
the equipment and the outside air.
For converters mounted in an enclosure, the ambient for the converters (internal air of the
cubicle or cabinet) is to be considered as a heat transfer agent and not as a cooling medium.
There is some reflection from the cabinet walls, which should be taken into account. Cubicle or
cabinet mounted assemblies shall comply with the overload conditions at maximum
temperature of the outside air.
2.2.2 Normal service conditions
The following limits shall apply unless otherwise specified.
2.2.2.1 Storage and transport temperatures
Minimum Maximum
Storage and transport −25 °C +55 °C
These limits apply with cooling liquid removed.

2.2.2.2 Operation including off-load periods
2.2.2.2.1 Temperatures of cooling air
Minimum Maximum
a) Extreme values −5 °C +40 °C
b) Daily average +35 °C
c) Yearly average +25 °C
2.2.2.2.2 Relative humidity of the ambient air
a) Minimum: 15 %.
b) Maximum: standard design converters are designed for the case where no condensation
can occur. If condensation is to be provided for, the case shall be treated as
special service condition (see 2.2.3).
2.2.2.2.3 Dust and solid particles content
Standard design equipment is indoor equipment, pollution degree 3A. (refer to Table 3 of
EN 50124-1).
Any condition exceeding PD 3A shall be specified by the purchaser as special service condition.
2.2.2.2.4 Vibrations
The equipment shall be suitable for installation in the vicinity of a rail track. Foundations shall be
designed to dampen the main effects of the passage of the trains. Nevertheless a limited
vibration or limited shocks can affect the equipment, which shall be capable of operating
satisfactorily when subjected to conventional sinusoidal vibrations at 10 Hz, separately applied
and having the following characteristics:
Peak acceleration Duration
Vertical acceleration: 5 m/s² 30 s
Horizontal acceleration: 5 m/s² 30 s
Any condition exceeding the above shall be specified by the purchaser.
2.2.2.3 Altitude
With regard to the use of air as cooling medium or heat transfer agent, altitudes up to 1 000 m
are considered as normal. If a converter is to be used at an altitude above 1 000 m but is tested
at normal altitude, the current capability shall be decreased by 1 % for each 100 m by which the
altitude of use exceeds 1 000 m in the case of natural air-cooling, and by 1,5 % for forced
air-cooling.
With regard to the dielectric properties of air, altitudes up to 2 000 m are considered as normal
(refer to EN 50124-1).
2.2.3 Special service conditions
The service conditions are assumed to be those listed under normal service conditions. The
following list gives examples of special service conditions that shall be subject to a special
agreement between purchaser and supplier:
a) special mechanical stresses, for example shocks and vibrations;
b) foreign particles in the ambient air, for example abnormal dirt or dust;

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c) salt air (for example proximity to the sea);
d) high values of relative humidity and/or temperature similar to those associated with tropical
climatic conditions;
e) other special service conditions not covered by this list or service conditions exceeding the
specified limits of normal service conditions.
In case special service conditions are required, the service conditions listed in EN 60721 should
preferably be used.
2.3 Electrical service conditions
2.3.1 General
For network conditions concerning the a.c. supply network reference shall be made to the
publications of IEC TC 77 and its subcommittees.
For network conditions concerning the traction supply network reference shall be made to
EN 50121-5, to EN 50124-1 and to EN 50163.
Information on prospective conditions of coexistence between supply systems, disturbing loads
and sensitive apparatus (mostly low current control equipment, other power converters, power
capacitors and sensitive lines such as used for communications, signalling and control) is
essential during the early stages of the design of an installation (notably: ratio of short-circuit
power to apparent power, presence of capacitors or other converters).
Guidance on calculation methods will be found in IEC 60146-1-2.
2.3.2 Limiting values as basis of rating
Unless otherwise specified, the converter shall be designed to operate under the service
conditions specified by the following limiting values.
2.3.2.1 Three-phase a.c. supply network
2.3.2.1.1 Frequency
Variation
Range ± 2 % of f
N
Rate of change ± 1 %/s
2.3.2.1.2 Voltage
Variation
Steady state + 10 % / - 10 % of U
N
Short time (0,5 to 30 cycles) + 15 % / - 15 %
2.3.2.1.3 Harmonics in supply voltage
Refer to IEC 61000-2-12 and EN 61000-2-4.
NOTE  A harmonic distortion of the a.c. supply voltage can cause overloads
− in 12 pulse rectifiers and their transformers due to unbalanced load sharing,
− in two parallel 6 pulse rectifiers with separate transformers due to unbalanced load sharing,
− in capacitive circuits of converters.

2.3.2.1.4 Repetitive and non-repetitive transients
On request the following characteristics shall be specified as far as possible:
a) transient energy available at the converter terminals (J);
b) rise time, (from 0,1 to 0,9 p.u. peak value) (µs);
c) peak value U /U (p.u.);
LRM LWM
d) peak value U /U (p.u.);
LSM LWM
e) duration above 50 % (t) (µs).

NOTE  For additional information on a.c. voltage waveforms, see IEC 60146-1-2.
Figure 3 - A.C. voltage waveform

2.3.2.2 Single-phase a.c. traction supply voltage

2.3.2.2.1 Frequency
The frequency range according to EN 50163 applies.
2.3.2.2.2 Voltage
The voltage range according to EN 50163 applies.
2.3.2.2.3 Harmonics
Refer to EN 61000-2-4.
2.3.2.2.4 Repetitive and non-repetitive transients
Refer to 2.3.2.1.4.
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2.3.2.3 d.c. traction supply voltage
Variation
Steady state + 20 % / − 33 % of U
n
Short time (1 s to 5 s) + 30 % / − 33 % of U
n
3 Converter equipment and assemblies
3.1 Electrical connections
Standard design converters for traction power supply usually are converters each individually
connected to a transformer for single phase (p = 2) or three-phase (p = 6 or 12) a.c. supply.
Twelve-pulse converters and dual six-pulse converters require two secondary windings in the
transformer with 30 electrical degree shifted connections, normally Y and D connected or two
separate transformers with different vector groups.
NOTE  Higher pulse numbers can be achieved by using transformers with appropriate phase shifting and
connecting several six-pulse or twelve-pulse converters in series or p
...