EN 61557-12:2008

Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 12: Performance measuring and monitoring devices (PMD)

Specifies requirements for combined performance measuring and monitoring devices that measure and monitor the electrical parameters within electrical distribution systems. These requirements also define the performance, in single and three-phase a.c. or d.c. systems having rated voltages up to 1 000 V a.c. or up to 1 500 V d.c. These devices are fixed installed or portable. They are intended to be used indoors and/or outdoors. This standard is not applicable for: - electricity metering equipment that complies with IEC 62053-21, IEC 62053-22 and IEC 62053-23. Nevertheless, uncertainties defined in this standard for active and reactive energy measurement are derived from those defined in the IEC 62053 standards series. - simple remote relays or simple monitoring relays. This standard is intended to be used in conjunction with IEC 61557-1 (unless otherwise specified), which specifies the general requirements for measuring and monitoring equipment, as required in IEC 60364-6. The standard does not include the measurement and monitoring of electrical parameters defined in Parts 2 to 9 of IEC 61557 or in IEC 62020. Combined performance measuring and monitoring devices (PMD), as defined in this standard, give additional safety information, which aids the verification of the installation and enhances the performance of the distribution systems. For instance, those devices help to check if the level of harmonics is still compliant with the wiring systems as required in IEC 60364-5-52. The combined performance measuring and monitoring devices (PMD) for electrical parameters described in this standard are used for general industrial and commercial applications. A PMD-A is a specific PMD complying with requirements of IEC 61000-4-30 class A, which may be used in 'power quality assessment' applications.

Elektrische Sicherheit in Niederspannungsnetzen bis AC 1 000 V und DC 1 500 V - Geräte zum Prüfen, Messen oder Überwachen von Schutzmaßnahmen - Teil 12: Kombinierte Geräte zur Messung und Überwachung des Betriebsverhaltens

Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1 500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 12: Dispositifs de mesure et de surveillance des performances (PMD)

Spécifie des exigences pour les dispositifs combinés de mesure et de surveillance des performances, qui mesurent et surveillent les paramètres électriques dans les réseaux de distribution électrique. Ces exigences définissent également les performances, dans les réseaux alternatifs ou continus monophasés et triphasés, ayant des tensions assignées inférieures ou égales à 1 000 V en courant alternatif ou inférieures ou égales à 1 500 V en courant continu. Ces dispositifs sont installés de manière fixe ou portables. Ils sont destinés à être utilisés à l'intérieur et/ou à l'extérieur. Cette norme n'est pas applicable: - aux appareils de comptage d'électricité qui sont conformes à la CEI 62053-21, la CEI 62053-22 et la CEI 62053-23. Néanmoins, les incertitudes définies dans la présente norme pour la mesure de l'énergie active et réactive sont tirées de celles définies dans la série de normes CEI 62053. - aux relais à distance simples ou aux relais de surveillance simples. La présente norme est destinée à être utilisée conjointement avec la CEI 61557-1 (sauf spécification contraire), qui spécifie les exigences générales pour les appareils de mesure et de surveillance, tel qu'il est exigé dans la CEI 60364-6. La norme n'inclut pas la mesure et la surveillance des paramètres électriques définis dans les Parties 2 à 9 de la CEI 61557 ou dans la CEI 62020. Les dispositifs combinés de mesure et de surveillance des performances (PMD), tels que définis dans la présente norme, donnent des informations supplémentaires sur la sécurité, ce qui contribue à la vérification de l'installation et augmente les performances des réseaux de distribution. Par exemple, ces dispositifs aident à vérifier si le niveau des harmoniques est toujours compatible avec les canalisations électriques, tel qu'exigé dans la CEI 60364-5-52. Ces dispositifs combinés de mesure et de surveillance des performances des paramètres électriques, décrits dans la présente norme, sont utilisés pour des applications industrielles et commerciales générales. Un PMD-A est un PMD spécifique, conforme aux exigences de la CEI 61000-4-30, classe A, qui peut être utilisé dans les applications d''évaluation de la qualité de l'alimentation.

Električna varnost v nizkonapetostnih razdelilnih sistemih izmenične napetosti do 1 kV in enosmerne napetosti do 1,5 kV - Oprema za preskušanje, merjenje ali nadzorovanje zaščitnih ukrepov - 12. del: Naprave za merjenje in nadzorovanje lastnosti/parametrov električnih omrežij (IEC 61557-12:2007)

General Information

• Status: Published
• Publication Date: 14-May-2008
• Withdrawal Date: 31-Mar-2011
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 29.080.01 - Electrical insulation in general
• ICS: 29.240.01 - Power transmission and distribution networks in general
• Technical Committee: CLC/TC 85X - Measuring equipment for electrical and electromagnetic quantities
• Drafting Committee: IEC/TC 85 - IEC_TC_85
• Parallel Committee: IEC/TC 85 - IEC_TC_85
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 15-May-2008
• Completion Date: 15-May-2008
• Directive: 2004/108/EC - Directive 2004/108/EC of the European Parliament and of the Council of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2004/108/EU - DIRECTIVE 2004/108/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2006/95/EC - Directive 2006/95/EC of the European Parliament and of the Council of 12 December 2006 on the harmonisation of the laws of Member States relating to electrical equipment designed for use within certain voltage limits (codified version)
• Directive: 2014/30/EU - Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility (recast)
• Directive: 2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
• Directive: 2014/53/EU - Directive 2014/53/EU of The European Parliament and of the Council of 16 April 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of radio equipment and repealing Directive 1999/5/EC
• Mandate: M/404 - Standardisation Mandate to CEN, CENELEC and ETSI for harmonized standard according to the Electro Magnetic Compatibility (EMC) Directive 2004/108/EC
• Ref Project: SIST EN 61557-12:2008 - Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures -- Part 12: Performance measuring and monitoring devices (PMD)

Relations

• Replaced By: EN IEC 61557-12:2022 - Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 12: Power metering and monitoring devices (PMD)
• Effective Date: 23-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2008
(OHNWULþQDYDUQRVWYQL]NRQDSHWRVWQLKUD]GHOLOQLKVLVWHPLKL]PHQLþQHQDSHWRVWLGR
N9LQHQRVPHUQHQDSHWRVWLGRN92SUHPD]DSUHVNXãDQMHPHUMHQMHDOL
QDG]RURYDQMH]DãþLWQLKXNUHSRYGHO1DSUDYH]DPHUMHQMHLQQDG]RURYDQMH
ODVWQRVWLSDUDPHWURYHOHNWULþQLKRPUHåLM,(&
Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or monitoring of protective measures -- Part 12:
Combined performance measuring and monitoring devices for electrical parameters
Elektrische Sicherheit in Niederspannungsnetzen bis AC 1 000 V und DC 1 500 V -
Geräte zum Prüfen, Messen oder Überwachen von Schutzmaßnahmen - Teil 12:
Kombinierte Geräte zur Messung und Überwachung des Betriebsverhaltens
Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1
500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de
protection - Partie 12: Dispositifs de mesure et de surveillance des performances (PMD)
Ta slovenski standard je istoveten z: EN 61557-12:2008
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.080.01 (OHNWULþQDL]RODFLMDQD Electrical insulation in
VSORãQR general
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61557-12
NORME EUROPÉENNE
May 2008
EUROPÄISCHE NORM
ICS 17.220.20; 29.080.01; 29.240.01

English version
Electrical safety in low voltage distribution systems
up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or monitoring of protective measures -
Part 12: Performance measuring and monitoring devices (PMD)
(IEC 61557-12:2007)
Sécurité électrique dans les réseaux  Elektrische Sicherheit
de distribution basse tension in Niederspannungsnetzen
de 1 000 V c.a. et 1 500 V c.c. - bis AC 1 000 V und DC 1 500 V -
Dispositifs de contrôle, de mesure ou Geräte zum Prüfen, Messen oder
de surveillance de mesures de protection - Überwachen von Schutzmaßnahmen -
Partie 12: Dispositifs de mesure et Teil 12: Kombinierte Geräte zur Messung
de surveillance des performances (PMD) und Überwachung des Betriebsverhaltens
(CEI 61557-12:2007) (IEC 61557-12:2007)

This European Standard was approved by CENELEC on 2008-04-01. 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, 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.

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.
Ref. No. EN 61557-12:2008 E
Foreword
The text of document 85/311/FDIS, future edition 1 of IEC 61557-12, prepared by IEC TC 85, Measuring
equipment for electrical and electromagnetic quantities, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 61557-12 on 2008-04-01.
This standard is to be used in conjunction with EN 61557-1:2007 (unless otherwise specified).
The following dates were fixed:

– latest date by which the EN has to be implemented

at national level by publication of an identical
(dop) 2009-01-01
national standard or by endorsement

– latest date by which the national standards conflicting
(dow) 2011-04-01
with the EN have to be withdrawn
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and covers essential requirements of
EC Directive 2004/108/EC. See Annex ZZ.
Annexes ZA and ZZ have been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61557-12:2007 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 60044-1 NOTE  Harmonized as EN 60044-1:1999 (modified).
IEC 60044-2 NOTE  Harmonized as EN 60044-2:1999 (modified).
IEC 60044-7 NOTE  Harmonized as EN 60044-7:2000 (not modified).
IEC 60044-8 NOTE  Harmonized as EN 60044-8:2002 (not modified).
IEC 60071-1 NOTE  Harmonized as EN 60071-1:2006 (not modified).
IEC 60359 NOTE  Harmonized as EN 60359:2002 (not modified).
IEC 61000-4-7 NOTE  Harmonized as EN 61000-4-7:2002 (not modified).
IEC 61140 NOTE  Harmonized as EN 61140:2002 (not modified).
IEC 62052-11 NOTE  Harmonized as EN 62052-11:2003 (not modified).
__________
- 3 - EN 61557-12:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.

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

1) 2)
IEC 60068-2-1 - Environmental testing - EN 60068-2-1 2007
Part 2-1: Tests - Test A: Cold

1) 2)
IEC 60068-2-2 - Environmental testing - EN 60068-2-2 2007
Part 2-2: Tests - Test B: Dry heat

1) 2)
IEC 60068-2-30 - Environmental testing - EN 60068-2-30 2005
Part 2-30: Tests - Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
1) 2)
IEC 60364-6 (mod) - Low voltage electrical installations - HD 60364-6 2007
Part 6: Verification
1) 2)
IEC 60529 - Degrees of protection provided by enclosures EN 60529 1991
(IP Code) + corr. May 1993
1) 2)
IEC 61000-4-5 - Electromagnetic compatibility (EMC) - EN 61000-4-5 2006
Part 4-5: Testing and measurement
techniques - Surge immunity test

1) 2)
IEC 61000-4-15 - Electromagnetic compatibility (EMC) - EN 61000-4-15 1998
Part 4-15: Testing and measurement
techniques - Flickermeter - Functional and
design specifications
IEC 61000-4-30 2003 Electromagnetic compatibility (EMC) - EN 61000-4-30 2003
Part 4-30: Testing and measurement
techniques - Power quality measurement
methods
IEC 61010 Series Safety requirements for electrical equipment EN 61010 Series
for measurement, control, and laboratory use

IEC 61010-1 2001 Safety requirements for electrical equipment EN 61010-1 2001
for measurement, control, and laboratory + corr. June 2002
use -
Part 1: General requirements
IEC 61326-1 2005 Electrical equipment for measurement, control EN 61326-1 2006
and laboratory use - EMC requirements -
Part 1: General requirements
IEC 61557-1 2007 Electrical safety in low voltage distribution EN 61557-1 2007
systems up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or
monitoring of protective measures -
Part 1: General requirements
1)
Undated reference.
2)
Valid edition at date of issue.

Publication Year Title EN/HD Year

IEC 62053-21 2003 Electricity metering equipment (a.c.) - EN 62053-21 2003
Particular requirements -
Part 21: Static meters for active energy
(classes 1 and 2)
IEC 62053-22 2003 Electricity metering equipment (a.c.) - EN 62053-22 2003
Particular requirements -
Part 22: Static meters for active energy
(classes 0,2 S and 0,5 S)
IEC 62053-23 2003 Electricity metering equipment (a.c.) - EN 62053-23 2003
Particular requirements -
Part 23: Static meters for reactive energy
(classes 2 and 3)
IEC 62053-31 1998 Electricity metering equipment (a.c.) - EN 62053-31 1998
Particular requirements -
Part 31: Pulse output devices for
electromechanical and electronic meters (two
wires only)
- 5 - EN 61557-12:2008
Annex ZZ
(informative)
Coverage of Essential Requirements of EC Directives
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers all
relevant essential requirements as given in Annex I of the EC Directive 2004/108/EC.
Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive concerned.
WARNING: Other requirements and other EC Directives may be applicable to the products falling within
the scope of this standard.
__________
IEC 61557-12
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective
measures –
Part 12: Performance measuring and monitoring devices (PMD)

Sécurité électrique dans les réseaux de distribution basse tension
de 1 000 V c.a. et 1 500 V c.c. – Dispositifs de contrôle, de mesure ou
de surveillance de mesures de protection –
Partie 12: Dispositifs de mesure et de surveillance des performances (PMD)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XC
CODE PRIX
ICS 17.220.20; 29.080.01; 29.240.01 ISBN 2-8318-9243.0

– 2 – 61557-12 © IEC:2007
CONTENTS
FOREWORD.6
INTRODUCTION.8

1 Scope.9
2 Normative references .10
3 Terms and definitions .11
3.1 General definitions .11
3.2 Definitions related to uncertainty and performance .12
3.3 Definitions related to electric phenomena .15
3.4 Definitions related to measurement techniques .18
3.5 Notations.18
3.5.1 Functions .18
3.5.2 Symbols and abbreviations.19
3.5.3 Indices .19
4 Requirements .19
4.1 General requirements.19
4.2 PMD general architecture .20
4.3 Classification of PMD .20
4.4 List of applicable performance classes .21
4.4.1 List of applicable function performance classes for PMD without
external sensors .21
4.4.2 List of applicable system performance classes for PMD with
external sensors .22
4.5 Operating and reference conditions for PMD .22
4.5.1 Reference conditions.22
4.5.2 Rated operating conditions .22
4.6 Start-up conditions .24
4.7 Requirements for PMD functions (except PMD-A).24
4.7.1 Active power (P) and active energy (E ) measurements .24
a
4.7.2 Reactive power (Q , Q ) and reactive energy (E , E ) measurements .29
A V rA rV
4.7.3 Apparent power (S , S ) and apparent energy (E , E )
A V apA apV
measurements.32
4.7.4 Frequency (f) measurements .34
4.7.5 R.m.s. phase current (I) and neutral current (I , I ) measurements.35
N Nc
4.7.6 R.m.s. voltage (U) measurements.38
4.7.7 Power factor (PF , PF ) measurements .40
A V
4.7.8 Short term flicker (P ) and long term flicker (P ) measurements.40
st lt
4.7.9 Voltage dip (U ) and voltage swell (U ) measurements .41
dip swl
4.7.10 Transients overvoltage (U ) measurements .43
tr
4.7.11 Voltage interruption (U ) measurements.43
int
4.7.12 Voltage unbalance (U , U ) measurements .44
nb nba
4.7.13 Voltage harmonics (U ) and voltage THD (THD and THD-R )
h u u
measurements.45

61557-12 © IEC:2007 – 3 –
4.7.14 Current harmonics (I ) and current THD (THD and THD-R )
h i i
measurements.46
4.7.15 Minimum, maximum, peak, three-phases average and demand
measurements.47
4.8 Requirements for PMD-A functions.47
4.9 General mechanical requirements .48
4.9.1 Vibration requirements .48
4.9.2 IP requirements .48
4.10 Safety requirements .49
4.10.1 Clearances and creepage distances .49
4.10.2 Connection of a fixed installed PMD with a current transformer .49
4.10.3 Connection of a PMD with a high voltage sensor .49
4.10.4 Accessible parts .49
4.10.5 Hazardous live parts.50
4.11 Analog outputs .50
4.11.1 General requirements .50
4.11.2 Compliance voltage .50
4.11.3 Analog output ripple content .50
4.11.4 Analog output response time .50
4.11.5 Limiting value of the analog output signal .50
4.11.6 Pulse outputs .51
5 Marking and operating instructions .51
5.1 Marking .51
5.2 Operating and installation instructions.51
5.2.1 General characteristics.51
5.2.2 Essential characteristics .52
5.2.3 Safety characteristics .54
6 Tests .54
6.1 Type tests of PMD.54
6.1.1 Test of temperature influence .55
6.1.2 Active power.55
6.1.3 Apparent power .58
6.1.4 Power factor .58
6.1.5 Common mode voltage rejection test .58
6.1.6 Frequency .59
6.1.7 Measurement of voltage harmonics .59
6.1.8 Measurement of current harmonics.59
6.1.9 Dips and swells .60
6.1.10 Voltage interruptions .60
6.1.11 Outputs tests .60
6.1.12 Climatic tests.61
6.1.13 EMC tests.62
6.1.14 Start up tests.62
6.2 Type tests of PMD-A .62
6.3 Routine tests .62
6.3.1 Protective bonding test .62
6.3.2 Dielectric strength test.63
6.3.3 Uncertainty test .63

– 4 – 61557-12 © IEC:2007
Annex A (informative) Definitions of electrical parameters .64
Annex B (normative) Definitions of minimum, maximum, peak and demand values .68
Annex C (informative) Intrinsic uncertainty, operating uncertainty, and overall system
uncertainty.70
Annex D (informative) Recommended sensor classes for the different kinds of PMD.72
Annex E (normative) Requirements applicable to PMD and to PMD-A.75

Bibliography.76

Figure 1 – PMD generic measurement chain.20
Figure 2 – Description of different types of PMD .21
Figure 3 – Relationship between ambient air temperature and relative humidity.24
Figure 4 – Waveform for odd harmonics influence test on active power measurement .55
Figure 5 – Spectral content for odd harmonics influence test on active power measurement .56
Figure 6 – Waveform for sub-harmonics influence test on active power measurement .57
Figure 7 – Spectral content for sub-harmonics influence test on active power measurement .57
Figure 8 – Common mode voltage influence testing .58
Figure 9 – Waveform for harmonics influence test on frequency measurement.59
Figure A.1 – Arithmetic and vector apparent powers in sinusoidal situation.66
Figure A.2 – Geometric representation of active and reactive power .67
Figure B.1 – Thermal current demand.68
Figure C.1 – Different kind of uncertainties .70

Table 1 – Classification of PMD .21
Table 2 – List of applicable function performance classes for PMD without external sensors 21
Table 3 – List of applicable system performance classes for PMD with external sensors.22
Table 4 – Reference conditions for testing .22
Table 5 – Rated operating temperatures for portable equipment .23
Table 6 – Rated operating temperatures for fixed installed equipment .23
Table 7 – Humidity and altitude operating conditions .23
Table 8 – Intrinsic uncertainty table for active power and active energy measurement .25
Table 9 – Influence quantities for active power and active energy measurement.26
Table 10 – Starting current for active power and active energy measurement .29
Table 11 – Intrinsic uncertainty table for reactive power and reactive energy measurement .29
Table 12 – Influence quantities for reactive power and reactive energy measurement.30
Table 13 – Starting current for reactive energy measurement .32
Table 14 – Intrinsic uncertainty table for apparent power and apparent
energy measurement .32
Table 15 – Influence quantities for apparent power and apparent energy measurement .33
Table 16 – Intrinsic uncertainty table for frequency measurement .34
Table 17 – Influence quantities for frequency measurement.34
Table 18 – Rated range of operation for phase current measurement .35
Table 19 – Rated range of operation for neutral current measurement .35

61557-12 © IEC:2007 – 5 –
Table 20 – Intrinsic uncertainty table for phase current .36
Table 21 – Intrinsic uncertainty table for neutral current measurement.36
Table 22 – Intrinsic uncertainty table for neutral current calculation .36
Table 23 – Influence quantities for phase current and neutral current measurement .37
Table 24 – Rated range of operation for r.m.s. voltage measurement.38
Table 25 – Intrinsic uncertainty table for r.m.s. voltage measurement .38
Table 26 – Influence quantities for r.m.s. voltage measurement .39
Table 27 – Intrinsic uncertainty table for power factor measurement .40
Table 28 – Intrinsic uncertainty table for flicker measurement .40
Table 29 – Rated range of operation for voltage dips and swells measurement.41
Table 30 – Intrinsic uncertainty table for voltage dips and swells measurement .41
Table 31 – Influence quantities for dips and swells measurement .42
Table 32 – Intrinsic uncertainty table for transient overvoltage measurement.43
Table 33 – Intrinsic uncertainty table for voltage interruption measurement .44
Table 34 – Intrinsic uncertainty table for voltage unbalance measurement .44
Table 35 – Rated range of operation for voltage harmonics measurement .45
Table 36 – Intrinsic uncertainty table for voltage harmonics measurement .45
Table 37 – Intrinsic uncertainty table for voltage THD or THD-R measurement .45
u u
Table 38 – Rated range of operation for current harmonics measurement.46
Table 39 – Intrinsic uncertainty table for current harmonics measurement .46
Table 40 – Intrinsic uncertainty table for current THD and THD-R measurement .47
i i
Table 41 – Complementary characteristics of PMD-A.48
Table 42 – Minimum IP requirements for PMD .49
Table 43 – PMD specification form.52
Table 44 – Characteristics specification template.53
Table 45 – Characteristics specification template.54
Table A.1 – Symbols definition.64
Table A.2 – Calculation definitions of electrical parameters, for 3 phase unbalanced
system with neutral .65
Table D.1 – PMD SD associated to current sensor or PMD DS associated to voltage
sensor .72
Table D.2 – PMD SS with Current Sensor and Voltage Sensor association .73
Table D.3 – Range of applicable performance classes for PMD without its associated
external sensors .74
Table D.4 – Range of applicable performance classes when calculating performance class of
PMD with its associated external sensors .74
Table D.5 – List of functions affected by uncertainty of external sensors.74
Table E.1 – Requirements applicable to PMD and to PMD-A.75

– 6 – 61557-12 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL SAFETY IN LOW VOLTAGE DISTRIBUTION SYSTEMS
UP TO 1 000 V a.c. AND 1 500 V d.c. –
EQUIPMENT FOR TESTING, MEASURING OR MONITORING
OF PROTECTIVE MEASURES –
Part 12: Performance measuring and monitoring devices (PMD)

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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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
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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 61557-12 has been prepared by IEC technical committee 85:
Measuring equipment for electrical and electromagnetic quantities.
The text of this standard is based on the following documents:
FDIS Report on voting
85/311/FDIS 85/312/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.

61557-12 © IEC:2007 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This standard is to be used in conjunction with IEC 61557-1 (unless otherwise specified).
A list of all parts of the IEC 61557 series, published under the general title Electrical safety in
low voltage distribution systems up to 1000 V a.c. and 1500 V d.c. – Equipment for testing,
measuring or monitoring of protective measures, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
– 8 – 61557-12 © IEC:2007
INTRODUCTION
As a complement to protection measures, it becomes more and more necessary to measure
different electrical parameters, in order to monitor the required performances in energy
distribution systems due to:
• installation standards evolutions, for instance over current detection is now a new
requirement for the neutral conductor due to harmonic content;
• technological evolutions (electronic loads, electronic measuring methods, etc.);
• end-users needs (cost saving, compliance with aspects of building regulations, etc.);
• safety and continuity of service;
• sustainable development requirements where energy measurement for instance is
recognised as an essential element of energy management, part of the overall drive to
reduce carbon emissions and to improve the commercial efficiency of manufacturing,
commercial organisations and public services.
The devices on the current market have different characteristics, which need a common
system of references. Therefore there is a need for a new standard in order to facilitate the
choices of the end-users in terms of performance, safety, interpretation of the indications, etc.
This standard provides a basis by which such devices can be specified and described, and
their performance evaluated.
61557-12 © IEC:2007 – 9 –
ELECTRICAL SAFETY IN LOW VOLTAGE DISTRIBUTION SYSTEMS
UP TO 1 000 V a.c. AND 1 500 V d.c. –
EQUIPMENT FOR TESTING, MEASURING OR MONITORING
OF PROTECTIVE MEASURES –
Part 12: Performance measuring and monitoring devices (PMD)

1 Scope
This part of IEC 61557 specifies requirements for combined performance measuring and
monitoring devices that measure and monitor the electrical parameters within electrical
distribution systems. These requirements also define the performance, in single and three-
phase a.c. or d.c. systems having rated voltages up to 1 000 V a.c. or up to 1 500 V d.c.
These devices are fixed installed or portable. They are intended to be used indoors and/or
outdoors. This standard is not applicable for:
• electricity metering equipment that complies with IEC 62053-21, IEC 62053-22 and
IEC 62053-23. Nevertheless, uncertainties defined in this standard for active and reactive
energy measurement are derived from those defined in the IEC 62053 standards series.
• simple remote relays or simple monitoring relays.
This standard is intended to be used in conjunction with IEC 61557-1 (unless otherwise
specified), which specifies the general requirements for measuring and monitoring equipment,
as required in IEC 60364-6.
The standard does not include the measurement and monitoring of electrical parameters
defined in Parts 2 to 9 of IEC 61557 or in IEC 62020.
Combined performance measuring and monitoring devices (PMD), as defined in this standard,
give additional safety information, which aids the verification of the installation and enhances
the performance of the distribution systems. For instance, those devices help to check if the
level of harmonics is still compliant with the wiring systems as required in IEC 60364-5-52.
The combined performance measuring and monitoring devices (PMD) for electrical
parameters described in this standard are used for general industrial and commercial
applications. A PMD-A is a specific PMD complying with requirements of IEC 61000-4-30
class A, which may be used in "power quality assessment" applications.
NOTE 1 Generally such types of devices are used in the following applications or for the following general needs:
– energy management inside the installation;
– monitoring and/or measurement of electrical parameters that may be required or usual;
– measurement and/or monitoring of the quality of energy.
NOTE 2 A measuring and monitoring device of electrical parameters usually consists of several functional
modules. All or some of the functional modules are combined in one device. Examples of functional modules are
mentioned below:
– measurement and indication of several electrical parameters simultaneously;

– 10 – 61557-12 © IEC:2007
– energy measurement and/or monitoring, and also sometimes compliance with aspects of building regulations;
– alarms functions;
– power quality (harmonics, over/undervoltages, voltage dips and swells, etc).
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2, Environmental testing – Part 2: Tests – Tests B: Dry heat
IEC 60068-2-30, Environmental testing – Part 2-30 – Tests –Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
IEC 60364-6, Low-voltage electrical installations – Part 6: Verification
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 61000-4-5, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test
IEC 61000-4-15, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 15: Flickermeter – Functional and design specifications
IEC 61000-4-30:2003, Electromagnetic compatibility (EMC) – Part 4-30: Testing and
measurement techniques – Power quality measurement methods
IEC 61010 (all parts), Safety requirements for electrical equipment for measurement, control,
and laboratory use
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1: General requirements
IEC 61326-1:2005, Electrical equipment for measurement, control and laboratory use – EMC
requirements – Part 1: General requirements
IEC 61557-1:2007, Electrical safety in low voltage distribution systems up to 1000 V a.c. and
1500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 1:
General requirements
IEC 62053-21:2003, Electricity metering equipment (a.c.) – Particular requirements – Part 21:
Static meters for active energy (classes 1 and 2)
IEC 62053-22:2003, Electricity metering equipment (a.c.) – Particular Requirements – Part 22:
Static meters for active energy (classes 0,2 S and 0,5 S)
IEC 62053-23:2003, Electricity metering equipment (a.c.) – Particular requirements – Part 23:
Static meters for reactive energy (classes 2 and 3)
IEC 62053-31:1998, Electricity metering equipment (a.c.) – Particular requirements – Part 31:
Pulse output devices for electromechanical and electronic meters (two wires only)

61557-12 © IEC:2007 – 11 –
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61557-1, unless
otherwise specified in this standard, and the following terms and definitions apply.
3.1 General definitions
3.1.1
performance measuring and monitoring device
PMD
combination in one or more devices of several functional modules dedicated to measuring and
monitoring electrical parameters in energy distribution systems or electrical installations. A
PMD can be used in connection with sensors (see 4.3)
A PMD that complies with class B as defined in IEC 61000-4-30 is also covered by this
definition.
NOTE 1 Under the generic term “monitoring” are also included functions of recording, alarm management etc.
NOTE 2 These devices may include power quality functions.
3.1.2
PMD-A
PMD in which all power quality assessment functions comply with measurement methods and
performance requirements according to class A of IEC 61000-4-30 and with complementary
requirements (safety, EMC, temperature range, complementary influence quantities, …) of
this standard
NOTE If this device is used for checking the compliance to the connection agreement with a network operator, it
should be installed at the interface point between the installation and the network.
3.1.3
power quality assessment functions
power quality functions whose measurement methods are defined in IEC 61000-4-30
3.1.4
specified external sensor
sensor that is chosen in such a way that, connected to a PMD without sensors, the system
performance class complies with 4. 4. 2
3.1.5
current sensor
CS
electrical, magnetic, optical or other device intended to transmit a signal corresponding to the
current flowing through the primary circuit of this device
NOTE A current transformer (CT) is in general a magnetic current sensor.
3.1.6
compliance voltage
value of the voltage that can be developed at the output of a current generator while
conforming to the requirement of the uncertainty specification for that output
NOTE This definition applies to current analogue output signals.

– 12 – 61557-12 © IEC:2007
3.1.7
voltage sensor
VS
electrical, magnetic, optical or other device intended to transmit a signal corresponding to the
voltage across the primary terminals of this device
NOTE A voltage transformer (VT) is in general a magnetic voltage sensor.
3.1.8
self-powered PMD
equipment able to work without an auxiliary power supply
NOTE 1 Self powered PMD have no provision for power supply terminals.
NOTE 2 Self powered PMD includes equipment powered from measurement inputs, internal batteries, or other
internal power sources (internal photo-voltaic sources, etc.).
3.1.9
auxiliary power supply
external power supply, either a.c. or d.c. that powers the PMD through dedicated terminals
separated from the measurement inputs of the PMD
3.2 Definitions related to uncertainty and performance
3.2.1
reference conditions
appropriate set of specified values and/or ranges of values of influence quantities under which
the
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