EN 50329:2003/A1:2010
(Amendment)Railway applications - Fixed installations - Traction transformers
Railway applications - Fixed installations - Traction transformers
2021: CLC legacy converted by DCLab NISOSTS
Bahnanwendungen - Ortsfeste Anlagen - Bahn-Transformatoren
Applications ferroviaires - Installations fixes - Transformateurs de traction
Železniške naprave - Stabilne naprave električne vleke - Transformatorji vlečnih tokokrogov
Zajema določene značilnosti transformatorjev vlečnih tokokrogov, kot je določeno v točki 1.3.1, ki se uporabljajo v postajah vlečnih tokokrogov ali vzporedno s progo za dobavljanje elektrike za sisteme vlečnih tokokrogov enosmerne ali izmenične napetosti ali za zagotavljanje elektrike do pomožnih storitev. Transformatorji vlečnih tokokrogov so: enofazni transformatorji vlečnih tokokrogov; - eno-, tri ali polifazni usmerjevalni-transformatorji ali pretvorni/frekvenčno-menjalni transformatorji za vozni vod z enosmerno ali izmenično napetostjo; enofazni avto-transformatorji za dobavo elektrike vlečnim tokokrogom; eno- ali trifazni pomožni transformatorji pri dobavni napetosti vlečnih tokokrogov.
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST EN 50329:2003/prAA:2008
01-september-2008
äHOH]QLãNHQDSUDYH6WDELOQHQDSUDYHHOHNWULþQHYOHNH7UDQVIRUPDWRUMLYOHþQLK
WRNRNURJRY
Railway applications - Fixed installations - Traction transformers
Bahnanwendungen - Ortsfeste Anlagen - Bahn-Transformatoren
Applications ferroviaires - Installations fixes - Transformateurs de traction
Ta slovenski standard je istoveten z: EN 50329:2003/prAA:2008
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
oSIST EN 50329:2003/prAA:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST EN 50329:2003/prAA:2008
oSIST EN 50329:2003/prAA:2008
DRAFT
EUROPEAN STANDARD
EN 50329
prAA
NORME EUROPÉENNE
June 2008
EUROPÄISCHE NORM
ICS 29.180; 29.280
English version
Railway applications -
Fixed installations -
Traction transformers
Applications ferroviaires - Bahnanwendungen -
Installations fixes - Ortsfeste Anlagen -
Transformateurs de traction Bahn-Transformatoren
This draft amendment prAA, if approved, will modify the European Standard EN 50329:2003; it is submitted to
CENELEC members for CENELEC enquiry.
Deadline for CENELEC: 2008-11-21.
It has been drawn up by CLC/SC 9XC.
If this draft becomes an amendment, CENELEC members are bound to comply with the CEN/CENELEC Internal
Regulations which stipulate the conditions for giving this amendment the status of a national standard without
any alteration.
This draft amendment was established by CENELEC 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, Bulgaria, 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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to
change without notice and shall not be referred to as a European Standard.
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
© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Project: 20527 Ref. No. EN 50329:2003/prAA:2008 E
Draft for Enquiry
oSIST EN 50329:2003/prAA:2008
EN 50329:2003/prAA:2008 – 2 –
1 Foreword
2 This draft amendment to the European Standard EN 50329:2003 was prepared by SC 9XC, Electric
3 supply and earthing systems for public transport equipment and ancillary apparatus (Fixed
4 installations), of Technical Committee CENELEC TC 9X, Electrical and electronic applications for
5 railways. It is submitted to the CENELEC enquiry.
6 __________
Draft for Enquiry
oSIST EN 50329:2003/prAA:2008
– 3 – EN 50329:2003/prAA:2008
7 Text of prAA to EN 50329:2003
8 1 General
9 1.2 Normative references
10 Delete the following normative references:
HD 464 S1 1988 Dry-type power transformers (IEC 60726:1982 + A1:1986, mod.)
+ A2 1991
+ A3
+ A4 1995
IEC 60354 1991 Loading guide for oil-immersed power transformers
11 Add the following normative references:
EN 60076-11 2004 Power transformers – Part 11: Dry-type transformers (IEC 60076-11:2004)
IEC 60076-7 2005 Power transformers – Part 7: Loading guide for oil-immersed power
transformers
12 2 General requirements for a traction transformer
13 Replace Subclause 2.2 by the following:
14 2.2 Checking of the capability of the transformer to sustain the stipulated load cycle
15 2.2.1 General
16 The temperature rise test shall be carried out in accordance with either EN 60076-2 or EN 60076-11
17 as applicable.
18 The current basis for determining the temperature rises shall be the rated service current (the
19 approximate relationship between the rated current and the rated service current is given in
20 Table C.3).
21 The resulting temperature rises after long-time overloads shall be within the limits of the temperature
22 rises prescribed in EN 60076-2 and EN 60076-11 under the stipulated ambient conditions and altitude.
23 The winding temperature rise after short-time overload conditions may exceed by 15 K the applicable
24 temperature rise limits according to EN 60076-2 and EN 60076-11.
25 When determining the temperature rises the effect of the harmonics should be considered as follows.
26 2.2.2 Temperature rise measurement for liquid immersed transformers
27 The procedure of 5.2.2 of EN 60076-2 is applicable with the exceptions mentioned here below. The
28 specified duty class or load cycle shall be taken into account. For transformers designed according to
29 a duty class the test cycles given in Figure A.1 to Figure A.3 apply.
30 The transformer in short circuit conditions shall be injected with a current causing the total losses. In
31 case of a traction converter transformer, the total losses are intended as the sum of the no-load loss
32 and of the total load losses determined according to Annex C.
Draft for Enquiry
oSIST EN 50329:2003/prAA:2008
EN 50329:2003/prAA:2008 – 4 –
33 Total losses calculated on the service current in basic load condition (I ) are injected as long to reach
BG
34 temperature steady-state conditions and then the long-term overload current is injected, for the
35 specified duration of said overload according to the duty class or load cycle. The final top oil
36 temperature rise shall be recorded.
37 For determining the temperature rises of windings, the transformer shall be subsequently loaded by
38 service currents representing the basic load (including the effect of harmonics), for the time necessary
39 to reach steady temperatures of the windings, and, for the respective durations, the service currents
40 corresponding to long-time overloads, and, when practicable and agreed between purchaser and
41 supplier, service currents corresponding to short-time overloads.
42 Measurements shall be taken at the end of the long-time overload duration and, when applicable, at
43 the end of the short-time overload duration. When actual measurements are found impossible, it is
44 allowed to agree to carry out calculations on temperature variations along the short-time load duration,
45 performed according to conventional methods.
46 IEC 60076-7 gives some guidance for such a calculation.
47 2.2.3 Temperature rise measurement for dry-type transformers
48 The requirements given in Clause 23 of EN 60076-11 apply taking into account that in the second part
49 of the test the losses attributable to the various stages of the current demand shall be calculated and
50 successively applied and the overloads for the respective duration. Annex C allows to determine total
51 load losses.
52 Measurements shall be taken at the end of the long-time overload duration and, when applicable, at
53 the end of the short-time overload duration. For transformers designed according to a duty class, the
54 test cycles given in Figure A.1 to Figure A.3 apply.
55 When actual measurements are not possible, it may be agreed to carry out calculations on
56 temperature variations along the short-time load duration, performed according to conventional
57 methods.
58 IEC 60905 gives some guidance for such a calculation.
59 2.2.4 Alternative criteria for determining temperature rise limits
60 On agreement between purchaser and manufacturer temperature limits and thermal ageing according
61 to IEC 60076-7 and IEC 60905 may be applied.
62 If the purchaser is able to define the load cycle in an extensive way as current demand, the capability
63 of the transformer to sustain this current demand shall be checked as follows:
64 – temperature rise and loss measurements shall be performed at sinusoidal load with rated service
65 current;
66 – based on these measurements, the top-oil temperature, the hot-spot temperatures of the
67 windings and the relative loss of life for the given current demand shall be calculated. The loss of
68 life calculation procedure of IEC 60076-7 can be used;
69 – the temperatures at the beginning of the load-cycle shall be set equal to those at the end of the
70 load cycle to consider a steady state condition; the maximum service temperature shall be taken
71 into account;
72 – the calculated relative loss of life for the load cycle shall be lower than 1;
73 – for oil immersed transformers, the maximum occasional hot-spot- temperature shall be lower than
74 140 °C and the maximum top oil temperature shall be lower than 115 °C during the load cycle;
75 – the influence of harmonics shall be considered as described in Annex C.
Draft for Enquiry
oSIST EN 50329:2003/prAA:2008
– 5 – EN 50329:2003/prAA:2008
76 For transformers designed according to a duty class, the text given in Figure A.1 to Figure A.3 applies.
77 Different temperature limits may be agreed between purchaser and supplier depending on the oil
78 characteristics.
79 2.8 Rating plate
80 Replace the reference to HD 464 by a reference to EN 60076-11.
81 4 Traction converter transformers
82 Replace Clause 4 by the following:
83 4 Traction converter transformers
84 4.1 General
85 The EN 61378 series specifies requirements for converter transformers for industrial use. This clause
86 specifies additional requirements for traction rectifier transformers of most common use in substations
87 with semiconductor diode rectifiers. Traction converter transformers for controlled converters need
88 additional considerations and are subject to special agreement between purchaser and supplier.
89 Transformers for 6-pulse three-phase bridge connections have one primary and one secondary
90 winding.
91 Transformers for 12-pulse rectifier connections have one or two primary windings and two secondary
92 windings with a 30° phase shift between the secondary windings. One secondary winding is commonly
93 star connected and the other is delta connected. Three types of rectifier transformers are preferably
94 used for 12-pulse traction rectifier groups:
95 a) three-windings transformer with one primary winding and two closely coupled secondary windings:
96 coupling factor K ≥ 0,9;
97 b) three-windings transformer with one primary winding and two loosely coupled secondary windings:
98 coupling factor 0,2 ≤ K < 0,9;
99 c) four-windings transformer with two primary windings and two uncoupled secondary windings:
100 coupling factor K < 0,2.
101 Three-windings transformers with closely coupled secondary windings are the preferred type for
102 12-pulse series connections and they are also used for 12-pulse parallel connections. The 12-pulse
103 parallel connection needs an interphase transformer between the two rectifier bridges.
104 NOTE 1 At low secondary voltages as for example for series connected rectifier groups for nominal voltage 750 V d.c. it is
105 practically impossible to reach a coupling factor K ≥ 0,9 due to the inductance of busbars.
106 Three-windings transformers with loosely coupled secondary windings are used for 12-pulse parallel
107 connections with interphase transformer where certain requirements regarding voltage characteristics
108 and maximum short-circuit current exist.
109 Four-windings transformers are used for 12-pulse parallel connections without the need of an
110 interphase transformer.
111 NOTE 2 It is recommended that 12-pulse rectifier groups with uncoupled rectifier transformers are not used with interphase
112 transformers. The impedance of the uncoupled transformer secondary windings performs a function similar to an interphase
113 transformer.
Draft for Enquiry
oSIST EN 50329:2003/prAA:2008
EN 50329:2003/prAA:2008 – 6 –
114 Other types of traction rectifier transformers are
115 – transformers using zigzag connections for 24-pulse rectifier connections,
116 – transformers with compensating windings.
117 These transformers need additional considerations and the particular requirements are subject to
118 agreement between purchaser and supplier.
119 It is assumed in EN 60076 that transformers are tested in sinusoidal conditions of voltage and current,
120 as applicable in the manufacturer's works or in a laboratory. The actual losses however are highly
121 influenced by the harmonic contents of the current, which depends on the characteristics of the
122 converter. To simplify the matter the only effect of the typical harmonics of each scheme are
123 considered, without any reference to the voltage harmonics, due to external sources and to those
124 harmonics, of negligible effect however, which appear in the actual operation of a converter. Refer to
125 EN 61378-1 for testing methods to include such harmonic effects.
126 The neutral point of a secondary star winding feeding a converter shall not be earthed and normally
127 needs not to be brought out.
128 4.2 Short-circuit impedance and load loss
129 4.2.1 Total load loss calculation
130 The losses shall be guaranteed at rated service current (see 10.4 of EN 60076-1). On purchaser’s
131 request, as an alternative, the losses at basic service current may be guaranteed.
132 The load loss, which appears under normal service conditions, is considered composed of the loss in
133 the winding resistance as measured by d.c. and the additional loss caused by eddy currents, as well
134 as by the stray flux in the windings and in the constructive parts.
135 The additional stray losses caused by the harmonics depend on the construction of the transformer,
136 on the firing angle and the commutation reactance and may vary in a wide range.
137 The calculation of total load loss of the traction transformer in converter operation (P ) may be
T
138 obtained through alternative methods; the purchaser shall state which method he intends to be applied
139 at the tender invitation stage, otherwise the method will be stated by the manufacturer.
140 In Annex C alternative methods for the calculation of load loss in
...
SLOVENSKI STANDARD
01-november-2010
äHOH]QLãNHQDSUDYH6WDELOQHQDSUDYHHOHNWULþQHYOHNH7UDQVIRUPDWRUMLYOHþQLK
WRNRNURJRY
Railway applications - Fixed installations - Traction transformers
Bahnanwendungen - Ortsfeste Anlagen - Bahn-Transformatoren
Applications ferroviaires - Installations fixes - Transformateurs de traction
Ta slovenski standard je istoveten z: EN 50329:2003/A1:2010
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 50329:2003/A1
NORME EUROPÉENNE
May 2010
EUROPÄISCHE NORM
ICS 29.180; 29.280
English version
Railway applications -
Fixed installations -
Traction transformers
Applications ferroviaires - Bahnanwendungen -
Installations fixes - Ortsfeste Anlagen -
Transformateurs de traction Bahn-Transformatoren
This amendment A1 modifies the European Standard EN 50329:2003; it was approved by CENELEC on
2010-05-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this amendment 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 amendment 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, 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
© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50329:2003/A1:2010 E
Foreword
This amendment to the European Standard EN 50329:2003 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
submitted to the formal vote and was approved by CENELEC as A1 to EN 50329:2003 on 2010-05-01.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the amendment has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop) 2011-05-01
– latest date by which the national standards conflicting
with the amendment have to be withdrawn
(dow) 2013-05-01
__________
– 3 – EN 50329:2003/A1:2010
1 General
1.2 Normative references
Delete the following normative references:
HD 464 S1 1988 Dry-type power transformers (IEC 60726:1982 + A1:1986, mod.)
+ A2 1991
+ A3 1992
+ A4 1995
IEC 60354 1991 Loading guide for oil-immersed power transformers
Add the following normative references:
EN 60076-11 2004 Power transformers – Part 11: Dry-type transformers (IEC 60076-11:2004)
IEC 60076-7 2005 Power transformers – Part 7: Loading guide for oil-immersed power
transformers
2 General requirements for a traction transformer
Replace Subclause 2.2 by the following:
2.2 Checking of the capability of the transformer to sustain the stipulated load cycle
2.2.1 General
The temperature rise test shall be carried out in accordance with either EN 60076-2 or EN 60076-11 as
applicable.
Basis for determining the temperature rises shall be the rated service current (the approximate
relationship between the rated current and the rated service current is given in Table C.3).
The resulting temperature rises after long-time overloads shall be within the limits of the temperature rises
prescribed in EN 60076-2 and EN 60076-11 under the stipulated ambient conditions and altitude.
The winding temperature rise after short-time overload conditions may exceed by 15 K the applicable
temperature rise limits according to EN 60076-2 and EN 60076-11.
When determining the temperature rises the effect of the harmonics should be considered according to
2.2.2, 2.2.3 and 2.2.4.
2.2.2 Temperature rise measurement for liquid immersed transformers
The procedure of 5.2.2 of EN 60076-2 shall be applied with the exceptions mentioned here below. The
specified duty class or load cycle shall be taken into account. For transformers designed according to a
duty class the test cycles given in Figure A.1 to Figure A.3 shall apply.
The transformer in short circuit conditions shall be injected with a current causing the total losses. In case
of a traction converter transformer, the total losses are intended as the sum of the no-load loss and of the
total load losses determined according to Annex C.
Total losses calculated on the service current in basic load condition (I ) are injected until it reaches
BG
temperature steady-state conditions and then the long-term overload current is injected, for the specified
duration of said overload according to the duty class or load cycle. The final top oil temperature rise shall
be recorded.
For determining the temperature rises of windings, the transformer shall be subsequently loaded by
service currents representing the basic load (including the effect of harmonics), for the time necessary to
reach steady temperatures of the windings, and, for the respective durations, the service currents
corresponding to long-time overloads, and, when practicable and agreed between purchaser and
supplier, service currents corresponding to short-time overloads.
Measurements shall be taken at the end of the long-time overload duration and, when applicable, at the
end of the short-time overload duration. When actual measurements are not possible, it may be agreed to
carry out calculations on temperature variations along the short-time load duration, performed according
to conventional methods.
IEC 60076-7 gives some guidance for such a calculation.
2.2.3 Temperature rise measurement for dry-type transformers
The requirements given in Clause 23 of EN 60076-11 apply taking into account that in the second part of
the test the losses attributable to the various stages of the current demand shall be calculated and
successively applied and the overloads for the respective duration. Annex C allows determining total load
losses.
Measurements shall be taken at the end of the long-time overload duration and, when applicable, at the
end of the short-time overload duration. For transformers designed according to a duty class, the test
cycles given in Figure A.1 to Figure A.3 apply.
When actual measurements are not possible, it may be agreed to carry out calculations on temperature
variations along the short-time load duration, performed according to conventional methods.
IEC 60905 gives some guidance for such a calculation.
2.2.4 Alternative criteria for determining temperature rise limits
On agreement between purchaser and manufacturer temperature limits and thermal ageing according to
IEC 60076-7 and IEC 60905 may be applied.
If the purchaser is able to define the load cycle in an extensive way as current demand, the capability of
the transformer to sustain this current demand shall be checked as follows:
– temperature rise and loss measurements shall be performed at sinusoidal load with rated service
current;
– based on these measurements, the top-oil temperature, the hot-spot temperatures of the windings
and the relative loss of life for the given current demand shall be calculated. The loss of life
calculation procedure of IEC 60076-7 may be used;
– the temperatures at the beginning of the load-cycle shall be set equal to those at the end of the load
cycle to consider a steady state condition; the maximum service temperature shall be taken into
account;
– the calculated relative loss of life for the load cycle shall be lower than 1;
– for oil immersed transformers, the maximum occasional hot-spot- temperature shall be lower than
140 °C and the maximum top oil temperature shall be lower than 115 °C during the load cycle;
– the influence of harmonics shall be considered as described in Annex C.
For transformers designed according to a duty class, the text given in Figure A.1 to Figure A.3 applies.
Different temperature limits may be agreed between purchaser and supplier depending on the oil
characteristics.
– 5 – EN 50329:2003/A1:2010
2.8 Rating plate
Replace the reference to HD 464 by a reference to EN 60076-11.
4 Traction converter transformers
Replace Clause 4 by the following:
4 Traction converter transformers
4.1 General
The EN 61378 series specifies requirements for converter transformers for industrial use. This clause
specifies additional requirements for traction rectifier transformers of most common use in substations
with semiconductor diode rectifiers. Traction converter transformers for controlled converters need
additional considerations and shall be subject to special agreement between purchaser and supplier.
Transformers for 6-pulse three-phase bridge connections have one primary and one secondary winding.
Transformers for 12-pulse rectifier connections have one or two primary windings and two secondary
windings with a 30° phase shift between the secondary windings. One secondary winding is commonly
star connected and the other is delta connected. Three types of rectifier transformers are preferably used
for 12-pulse traction rectifier groups:
a) three-windings transformer with one primary winding and two closely coupled secondary windings:
coupling factor K ≥ 0,9;
b) three-windings transformer with one primary winding and two loosely coupled secondary windings:
coupling factor 0,2 ≤ K < 0,9;
c) four-windings transformer with two primary windings and two uncoupled secondary windings:
coupling factor K < 0,2.
Three-windings transformers with closely coupled secondary windings are the preferred type for 12-pulse
series connections and they are also used for 12-pulse parallel connections. The 12-pulse parallel
connection needs an interphase transformer between the two rectifier bridges.
NOTE 1 At low secondary voltages as for example for series connected rectifier groups for nominal voltage 750 V d.c. it is
practically impossible to reach a coupling factor K ≥ 0,9 due to the inductance of busbars.
Three-windings transformers with loosely coupled secondary windings are used for 12-pulse parallel
connections with interphase transformer where certain requirements regarding voltage characteristics and
maximum short-circuit current exist.
Four-windings transformers are used for 12-pulse parallel connections without the need of an interphase
transformer.
NOTE 2 It is recommended that 12-pulse rectifier groups with uncoupled rectifier transformers are not used with interphase
transformers. The impedance of the uncoupled transformer secondary windings performs a function similar to an interphase
transformer.
Other types of traction rectifier transformers are
– transformers using zigzag connections for 24-pulse rectifier connections,
– transformers with compensating windings.
These transformers need additional considerations and the particular requirements are subject to
agreement between purchaser and supplier.
It is assumed in EN 60076 that transformers are tested in sinusoidal conditions of voltage and current, as
applicable in the manufacturer's works or in a laboratory. The actual losses however are highly influenced
by the harmonic contents of the current, which depends on the characteristics of the converter. To
simplify the matter the only effect of the typical harmonics of each scheme are considered, without any
reference to the voltage harmonics, due to external sources and to those harmonics, of negligible effect
however, which appear in the actual operation of a converter. Refer to EN 61378-1 for testing methods to
include such harmonic effects.
The neutral point of a secondary star winding feeding a converter shall not be earthed and normally
needs not to be brought out.
4.2 Short-circuit impedance and load loss
4.2.1 Total load loss calculation
The losses shall be guaranteed at rated service current (see 10.4 of EN 60076-1). On purchaser’s
request, as an alternative, the losses at basic service current may be guaranteed.
The load loss, which appears under normal service conditions, is considered composed of the loss in the
winding resistance as measured by d.c. and the additional loss caused by eddy currents, as well as by
the stray flux in the windings and in the constructive parts.
The additional stray losses caused by the harmonics depend on the construction of the transformer, on
the firing angle and the commutation reactance and may vary in a wide range.
The calculation of total load loss of the traction transformer in converter operation (P ) may be obtained
T
through alternative methods; the purchaser shall state which method he intends to be applied at the
tender invitation stage, otherwise the method will be stated by the manufacturer.
In Annex C alternative methods for the calculation of load loss in transformers during converter operation
are given.
4.2.2 Impedance
NOTE For the definition of impedance see 3.7 of EN 60076-1.
The short-circuit impedance shall be measured and recorded between each pair of wind
...
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