Measuring relays and protection equipment - Part 149: Functional requirements for thermal electrical relays

This part of the IEC 60255 series specifies minimum requirements for thermal protection relays. This standard includes specification of the protection function, measurement characteristics and test methodologies. The object of this standard is to establish a common and reproducible reference for evaluating dependent time relays which protect equipment from thermal damage by measuring a.c. current flowing through the equipment. Complementary input energizing quantities such as ambient, coolant, top oil and winding temperature may be applicable for the thermal protection specification set forth in this standard. This standard covers protection relays based on a thermal model with memory function. The test methodologies for verifying performance characteristics of the thermal protection function and accuracy are also included in this Standard. This standard does not intend to cover the thermal overload protection trip classes indicated in IEC 60947-4-1 and IEC 60947-4-2, related to electromechanical and electronic protection devices for low voltage motor-starters.

/

Relais de mesure et dispositifs de protection - Partie 149: Exigences fonctionnelles pour les relais électriques thermiques

La CEI 60255-149:2013 spécifie les exigences minimales relatives aux relais de protection thermique. Cette norme inclut la spécification de la fonction de protection, les caractéristiques de mesure et les méthodes d'essais. L'objet est d'établir une référence commune et reproductible pour des relais à temps dépendant qui protègent un dispositif contre les détériorations thermiques par la mesure du courant alternatif circulant dans le dispositif. Des grandeurs d'alimentation d'entrée complémentaire, telles que la mesure de la température ambiante, du liquide de refroidissement, de l'huile isolante, des enroulements, peuvent être applicables pour la spécification de protection thermique définie dans la présente norme. La présente norme couvre les relais de protection basés sur un modèle thermique à fonction de mémoire.

Merilni releji in zaščitna oprema - 149. del: Funkcionalne zahteve za termoelektrične releje

Ta del skupine standardov IEC 60255 določa minimalne zahteve za toplotne zaščitne releje. Ta standard zajema specifikacije zaščitne funkcije, merilnih značilnosti in preskusnih metodologij. Cilj tega standarda je vzpostaviti splošno in ponovljivo sklicevanje za oceno odvisnih časovnih relejev, ki opremo ščitijo pred toplotno škodo z merjenjem izmeničnega toka, ki teče skozi opremo. Dopolnilne vhodne energetske veličine, kot so temperatura okolja, hladilnega sredstva, vrhnjega olja in navitja, se lahko uporabljajo za specifikacijo toplotne zaščite iz tega standarda. Ta standard zajema zaščitne releje na podlagi toplotnega modela s spominsko funkcijo. Tudi preskusne metodologije za preverjanje zahtevanih lastnosti toplotne zaščitne funkcije in točnosti so zajete v tem standardu. Ta standard ni namenjen obravnavi razredov odklopnikov za zaščito pred toplotno preobremenitvijo iz standardov IEC 60947-4-1 in IEC 60947-4-2 v zvezi z elektromehanskimi in elektronskimi zaščitnimi napravami za nizkonapetostne zaganjalnike motorjev.

General Information

Status
Published
Publication Date
05-Dec-2013
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-Nov-2013
Due Date
30-Jan-2014
Completion Date
06-Dec-2013

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SLOVENSKI STANDARD
SIST EN 60255-149:2014
01-januar-2014
1DGRPHãþD
SIST EN 60255-8:2001
0HULOQLUHOHMLLQ]DãþLWQDRSUHPDGHO)XQNFLRQDOQH]DKWHYH]D
WHUPRHOHNWULþQHUHOHMH
Measuring relays and protection equipment - Part 149: Functional requirements for
thermal electrical relays
/
Relais de mesure et dispositifs de protection - Partie 149: Exigences fonctionnelles pour
les relais électriques thermiques
Ta slovenski standard je istoveten z: EN 60255-149:2013
ICS:
29.120.70 Releji Relays
SIST EN 60255-149:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60255-149:2014

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SIST EN 60255-149:2014

EUROPEAN STANDARD
EN 60255-149

NORME EUROPÉENNE
October 2013
EUROPÄISCHE NORM

ICS 29.120.70 Supersedes EN 60255-8:1998


English version


Measuring relays and protection equipment -
Part 149: Functional requirements for thermal electrical relays
(IEC 60255-149:2013)


Relais de mesure et dispositifs de Messrelais und Schutzeinrichtungen -
protection - Teil 149: Funktionsanforderungen an den
Partie 149: Exigences fonctionnelles pour thermischen Überlastschutz
les relais électriques thermiques (IEC 60255-149:2013)
(CEI 60255-149:2013)





This European Standard was approved by CENELEC on 2013-09-03. 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
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


© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60255-149:2013 E

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SIST EN 60255-149:2014
EN 60255-149:2013 - 2 -

Foreword

The text of document 95/313/FDIS, future edition 1 of IEC 60255-149, prepared by IEC/TC 95
"Measuring relays and protection equipment" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN 60255-149:2013.

The following dates are fixed:
(dop) 2014-06-03
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2016-09-03
standards conflicting with the
document have to be withdrawn

This document supersedes EN 60255-8:1998.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 60255-149:2013 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60034-11 NOTE  Harmonized as EN 60034-11.
IEC 60947-4-1 NOTE  Harmonized as EN 60947-4-1.
IEC 60947-4-2 NOTE  Harmonized as EN 60947-4-2.
IEC 61850-9-2 NOTE  Harmonized as EN 61850-9-2.

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SIST EN 60255-149:2014
- 3 - EN 60255-149:2013

Annex ZA
(normative)
Normative references to i nternational publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60050 Series International Electrotechnical Vocabulary - -
(IEV)


IEC 60085 2007 Electrical insulation - Thermal evaluation and EN 60085 2008
designation


IEC 60255-1 - Measuring relays and protection equipment - EN 60255-1 -
Part 1: Common requirements


IEC 61850-7-4 - Communication networks and systems for EN 61850-7-4 -
power utility automation -
Part 7-4: Basic communication structure -
Compatible logical node classes and data
object classes

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SIST EN 60255-149:2014

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SIST EN 60255-149:2014




IEC 60255-149

®


Edition 1.0 2013-07




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Measuring relays and protection equipment –

Part 149: Functional requirements for thermal electrical relays




Relais de mesure et dispositifs de protection –

Partie 149: Exigences fonctionnelles pour relais électriques thermiques
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX X


ICS 29.120.70 ISBN 978-2-8322-1005-5



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 60255-149:2014
– 2 – 60255-149 © IEC:2013
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Specification of the function . 8
4.1 General . 8
4.2 Input energizing quantities/energizing quantities . 9
4.3 Binary input signals . 9
4.4 Functional logic . 10
4.4.1 Equivalent heating current . 10
4.4.2 Basic (setting) and operating current values for thermal protection . 10
4.4.3 Thermal level calculation . 11
4.4.4 Time-current limit characteristic equations and curves . 12
4.4.5 Thermal level alarm threshold . 14
4.5 Binary output signals . 15
4.5.1 General . 15
4.5.2 Operate (trip) output signal . 15
4.5.3 Alarm signal . 15
4.5.4 Other binary output signals . 15
4.6 Additional influencing factors on thermal protection . 16
4.6.1 General . 16
4.6.2 Influence of ambient temperature on thermal protection . 16
4.6.3 Thermal reset facilities . 16
4.7 Behaviour of thermal protective device during auxiliary power supply failure . 17
5 Performance specification . 17
5.1 Accuracy related to the characteristic quantity . 17
5.2 Accuracy related to the operate time . 17
5.3 Performance during frequency variations . 18
6 Functional test methodology . 18
6.1 General . 18
6.2 Determination of steady-state errors related to the operating current value . 19
6.3 Determination of steady-state errors related to the characteristic quantity and
the operate time . 19
6.3.1 Accuracy determination of the cold curve . 19
6.3.2 Accuracy determination of the hot curves . 20
6.4 Performance with specific cooling thermal time constant . 21
6.5 Performance with harmonics . 22
6.6 Performance during frequency variations . 22
6.7 Performance during different ambient temperatures . 23
7 Documentation requirements . 24
7.1 Type test report . 24
7.2 Other user documentation . 24
Annex A (informative) Simple first-order thermal model of electrical equipment. 26
Annex B (informative) Thermal electrical relays which use temperature as setting
parameters . 41
Bibliography . 46

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SIST EN 60255-149:2014
60255-149 © IEC:2013 – 3 –

Figure 1 – Simplified thermal protection function block diagram . 9
Figure 2 – Typical examples of characteristic curves for cold state of a first-order
thermal system with no previous load before overload occurs . 13
Figure 3 – Typical examples of characteristic curves for hot states of a first-order
thermal system for different values of previous load before overload occurs . 14
Figure A.1 – An electrical equipment to be thermally protected represented as a
simple first-order thermal system . 26
Figure A.2 – Equivalence between a first-order thermal system and an electric parallel
RC circuit . 30
Figure A.3 – Analogue thermal circuit representation of a simple first-order thermal
system . 31
Figure A.4 – Analogue thermal circuit representation of a simple first-order thermal
system – motor starting condition . 31
Figure A.5 – Analogue thermal circuit representation of a simple first-order thermal
system – motor stopped condition . 31
Figure A.6 – Dynamic step response of a simple first-order thermal system algorithm to
a current below pickup . 33
Figure A.7 – Dynamic step response of a first-order thermal system (cold initial state) . 34
Figure A.8 – Dynamic step response of a first-order thermal system (hot initial state) . 34
Figure A.9 – Dynamic step response of a first-order thermal system to a load current
followed by an overload current (initial state: cold) . 35
Figure A.10 – Dynamic step response of a first-order thermal system to a load current
followed by an overload current (initial state: hot) . 35

Table 1 – Limiting error as multiples of assigned error . 18
Table 2 – Test points of the cold curve . 20
Table 3 – Test points of the hot curve . 21
Table 4 – Test points of the cold curve with harmonics . 22
Table 5 – Test points of the cold curve during frequency variations . 22
Table A.1 – Thermal and electrical models . 30
Table A.2 – Thermal insulation classes and maximum temperatures, according to
IEC 60085. 40
Table A.3 – Example of correction factor values (F ) for class F equipment according
a
to the ambient temperature (T ) . 40
a

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SIST EN 60255-149:2014
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________

MEASURING RELAYS AND PROTECTION EQUIPMENT –

Part 149: Functional requirements for thermal electrical relays


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60255-149 has been prepared by IEC technical committee 95:
Measuring relays and protection equipment.
This first edition cancels and replaces IEC 60255-8, published in 1990.
The text of this standard is based on the following documents:
FDIS Report on voting
95/313/FDIS 95/317/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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SIST EN 60255-149:2014
60255-149 © IEC:2013 – 5 –
A list of all parts of IEC 60255 series, under the general title Measuring relays and protection
equipment, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.

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SIST EN 60255-149:2014
– 6 – 60255-149 © IEC:2013
MEASURING RELAYS AND PROTECTION EQUIPMENT –

Part 149: Functional requirements for thermal electrical relays



1 Scope
This part of the IEC 60255 series specifies minimum requirements for thermal protection
relays. This standard includes specification of the protection function, measurement
characteristics and test methodologies.
The object of this standard is to establish a common and reproducible reference for evaluating
dependent time relays which protect equipment from thermal damage by measuring a.c.
current flowing through the equipment. Complementary input energizing quantities such as
ambient, coolant, top oil and winding temperature may be applicable for the thermal protection
specification set forth in this standard. This standard covers protection relays based on a
thermal model with memory function.
The test methodologies for verifying performance characteristics of the thermal protection
function and accuracy are also included in this Standard.
This standard does not intend to cover the thermal overload protection trip classes indicated
in IEC 60947-4-1 and IEC 60947-4-2, related to electromechanical and electronic protection
devices for low voltage motor-starters.
The thermal protection functions covered by this standard are as follows:

Protection function IEC 61850-7-4 IEEE C37.2
PTTR
Thermal overload protection 49
Rotor thermal overload protection PROL 49R
Stator thermal overload protection PSOL 49S

General requirements for measuring relays and protection equipment are specified in
IEC 60255-1.
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.
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at
http://www.electropedia.org)
IEC 60085, Electrical insulation – Thermal evaluation and designation
IEC 60255-1, Measuring relays and protection equipment – Part 1: Common requirements
IEC 61850-7-4, Communication networks and systems for power utility automation – Part 7-4:
Basic communication structure – Compatible logical node classes and data classes

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SIST EN 60255-149:2014
60255-149 © IEC:2013 – 7 –
3 Terms and definitions
For the purpose of this document, the terms and definitions given in IEC 60050-447, as well
as the following apply.
3.1
hot curve
for a thermal electrical relay with a total memory function, characteristic curve representing
the relationship between specified operating time and current, taking into account thermal
effect of a specified steady-state load current before the overload occurs
Note 1 to entry: Hot curve is a plot of a particular time-current solution for a first-order thermal system differential
equation, assuming a specific constant overload current and a specific preload current.
3.2
cold curve
for a thermal electrical relay, characteristic curve representing the relationship between
specified operating time and current, with the relay at reference and steady-state conditions
with no-load current flowing before the overload occurs
Note 1 to entry: Cold curve is a plot of a particular time-current solution for a first-order thermal system
differential equation, assuming a specific constant overload current when there is no preload.
3.3
basic current
I
B
specified limiting (nominal) value of the current for which the relay is required not to operate
at steady-state conditions of the equipment to be thermally protected
Note 1 to entry: The basic current serves as a reference for the definition of the operational characteristics of
thermal electrical relays. The basic settings of a thermal electrical protection function are made in terms of this
basic current (I ) and the thermal time constant (τ) of the protected equipment.
B
3.4
equivalent heating current
I
eq
current which takes into account the additional heating sources such as imbalance currents
and/or harmonics
3.5
factor k
factor by which the basic current (I ) is multiplied to obtain the maximum permissible
B
continuous operating current value of the equipment to be thermally protected, which is used
in the thermal characteristic function
Note 1 to entry: The factor k indicates the maximum permissible constant between phase current (full load) and
the basic (nominal) current of the protected equipment.
3.6
previous load ratio
ratio of the load current preceding the overload to basic current under specified conditions
3.7
reference limiting error
limiting error determined under reference conditions
[SOURCE: IEC 60050:2010, 447-08-07]

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SIST EN 60255-149:2014
– 8 – 60255-149 © IEC:2013
3.8
temperature rise
difference between the temperature of the part under consideration and a reference
temperature
Note 1 to entry: The reference temperature may be for example the ambient air temperature or the temperature of
a cooling fluid.
[SOURCE: IEC 60050:2001, 151-16-26]
3.9
thermal equilibrium
thermal state reached when the temperature rise of the several parts of the machine do not
vary by more than a gradient of 2 K per hour
[SOURCE: IEC 60050:1996, 411-51-08]
3.10
thermal time constant
T
th
time required for the temperature rise of the protected equipment relative to its initial
temperature, to reach 63,2 % of its final, asymptotic value following a step increase in current
Note 1 to entry: The initial temperature for example can be ambient temperature.
3.11
thermal level
H
ratio expressed in percentage between the estimated actual temperature of the equipment
and the temperature of the equipment when the equipment is operating at its maximum
current (k × I ) for a long period, enough to allow equipment to reach its thermal equilibrium
B
4 Specification of the function
4.1 General
An example of a thermal protection function with its input energizing quantities, binary input
signals, operate (trip), alarm and other binary outputs, and functional logic which includes
measuring element, thermal level calculation, settings, and thresholds are shown in Figure 1.
The manufacturer shall provide the functional block diagram of the specific thermal protection
implementation.

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SIST EN 60255-149:2014
60255-149 © IEC:2013 – 9 –
Thermal protection functional logic
Thresholds
Operate (trip)
Settings
(trip, alarm) signal
Input
Energizing
Measuring
energizing
quantities
quantites element
(signal
(equivalent
processing)
heating
current)
Thermal
Alarm (pre-
operate) signal
level
calculation
Ambient / winding
To other
temperature
protection
measuring
functions
Binary
(option)
input
signals
Other binary
The exact and complete contents of this functional logic block diagram area
output signals
depends upon the implementation

IEC  1846/13
Figure 1 – Simplified thermal protection function block diagram
4.2 Input energizing quantities/energizing quantities
The input energizing quantities are the measuring signals, such as phase (or line) currents,
and ambient/environmental or winding temperatures (if required or applicable). Their ratings
and relevant requirements are specified in IEC 60255-1.
Input energizing quantities can be presented to the thermal protection functional logic either
hardwired from current transformers and any additional input quantities such as ambient or
winding temperature, or as a data packet over a communication ports using an appropriate
data communication protocol, such as IEC 61850-9-2.
The input energizing quantities used by the thermal protection function need not be the
current directly taken from the secondary side of the current transformers. Therefore the
protection relay documentation shall state the type of energizing quantities used by the
thermal protection function.
Examples of input energizing quantities are:
– single-phase current measurement;
– three-phase current measurement;
– positive and negative sequence current measurement;
– winding or ambient temperature sensor.
NOTE The ambient temperature, coolant temperature, top oil temperature or winding temperature of the
equipment to be thermally protected can be measured by temperature sensors, such as resistance temperature
detector (RTD), the values of which can be used for biasing the calculation of the thermal level replica specified in
this standard. Output signals or values of these temperature sensors can be taken into account for the first-order
thermal model algorithm, which can influence and compensate the calculated thermal level (based on the
equivalent heating current and heating thermal time constant values).
4.3
...

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