IEC 62888-2:2018

Railway applications - Energy measurement on board trains - Part 2: Energy measurement

IEC 62888-2:2018 specifies the requirements applicable to the Energy Measurement Function (EMF) of an Energy Measurement System (EMS) for use on board traction units for measurement of energy supplied directly from/to the Contact Line system. This document also gives requirements for the Current Measurement Function (e.g. current sensor), the Voltage Measurement Function (e.g. voltage sensor) and the Energy Calculation Function (e.g. energy meter).

Applications ferroviaires - Mesure d'énergie à bord des trains - Partie 2: Mesure d'énergie

L'IEC 62888-2:2018 définit les exigences applicables à la fonction de mesure d'énergie (EMF) d’un système de mesure d’énergie (EMS) utilisé à bord d’unités de tractions pour la mesure de l’énergie fournie directement depuis/vers le système de ligne de contact. Le présent document donne également les exigences pour la fonction de mesure de courant (ex: capteur de courant), la fonction de mesure de tension (ex: capteur de tension) et la fonction de calcul d'énergie (ex: compteur d’énergie).

General Information

• Status: Published
• Publication Date: 24-Jan-2018
• ICS: 01.040.29 - Electrical engineering (Vocabularies)
• ICS: 33.100 - Electromagnetic compatibility (EMC)
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: TC 9 - Electrical equipment and systems for railways
• Drafting Committee: MT 62888 - TC 9/MT 62888
• Current Stage: PPUB - Publication issued
• Start Date: 25-Jan-2018
• Completion Date: 29-Dec-2017

Overview

IEC 62888-2:2018 is an international standard developed by the International Electrotechnical Commission (IEC) focusing on energy measurement systems on board railway traction units. Specifically, it covers the requirements for the Energy Measurement Function (EMF) that measures energy supplied to or from trains via contact line systems. This standard also defines specifications for the related components including current sensors, voltage sensors, and energy calculation functions. Its purpose is to ensure accurate, reliable, and consistent energy measurement critical for energy management, billing, and operational efficiency in railway applications.

Key Topics

• Energy Measurement Function (EMF): Defines the functional and accuracy requirements for measuring energy flow on traction units, including managing traction supply system changes and providing re-verification guidelines.

• Sensors: Requirements for the Current Measurement Function (CMF) and Voltage Measurement Function (VMF) cover operational accuracy, electrical characteristics, and conformity to withstand typical railway electrical environments.

• Energy Calculation Function (ECF): Specifies how measured voltage and current are processed to calculate energy usage, addressing accuracy, electromagnetic compatibility, temperature effects, and data transfer protocols.

• Testing and Verification: Outlines procedures for conformance, type, routine testing, and design reviews to assure measurement accuracy and system durability over time. Includes testing under external electromagnetic influences and temperature variations.

• Functional Architecture: Provides detailed functional block diagrams and system configurations illustrating EMS dataflow on trains.

Applications

IEC 62888-2:2018 is critical for railway operators, manufacturers, and maintenance organizations involved in:

• On-board Energy Management: Ensuring precise measurement enables energy-efficient train operation and optimization of power consumption.

• Energy Billing and Settlement: Accurate energy quantification is fundamental for fair billing based on actual train energy usage and regeneration.

• Traction Unit Design: Guiding engineering design of traction systems, sensors, and energy meters to meet interoperability and regulatory requirements.

• Maintenance and Compliance: Establishing test regimes and re-verification protocols to maintain measurement accuracy throughout equipment lifecycle.

• Integration with Railway Systems: Supporting data communication from energy meters to centralized systems for monitoring and analysis.

Related Standards

For comprehensive railway energy measurement and management, IEC 62888-2:2018 complements other standards such as:

• IEC 62888-1: Covers broader aspects of railway on-board energy measurement systems including system architecture and data management.

• IEC 61968 / IEC 61850: Related to communication protocols and interoperability of electrical equipment in railway and power systems.

• IEC 61000 Series: Electromagnetic compatibility (EMC) standards pertinent for ensuring immunity and emission levels in measurement equipment.

• ISO/TC 269 Railway Applications: Provides additional guidelines on railway electrification and energy systems.

Understanding and applying IEC 62888-2:2018 ensures that energy measurement on board trains meets global standards for accuracy, reliability, and safety, fostering efficient railway energy usage and enhanced sustainability initiatives.

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Keywords: IEC 62888-2, railway energy measurement, traction unit energy meter, contact line energy measurement, energy calculation function, current sensor requirements, voltage sensor standards, railway applications energy, energy management system, traction energy accuracy, electromagnetic compatibility railway, re-verification testing railway energy meters.

Standards Content (Sample)

IEC 62888-2 ®
Edition 1.0 2018-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Railway applications – Energy measurement on board trains –
Part 2: Energy measurement
Applications ferroviaires – Mesure d'énergie à bord des trains –
Partie 2: Mesure d'énergie
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IEC 62888-2 ®
Edition 1.0 2018-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Railway applications – Energy measurement on board trains –

Part 2: Energy measurement
Applications ferroviaires – Mesure d'énergie à bord des trains –

Partie 2: Mesure d'énergie
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 45.060.01 ISBN 978-2-8322-5152-2

– 2 – IEC 62888-2:2018  IEC 2018
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 11
2 Normative references . 12
3 Terms, definitions, abbreviated terms and symbols . 14
3.1 Terms and definitions . 14
3.2 Abbreviated terms . 17
3.3 Symbols . 18
4 Requirements . 18
4.1 General . 18
4.2 Energy Measurement Function (EMF) . 18
4.2.1 General . 18
4.2.2 Electrical requirements . 19
4.2.3 Accuracy requirements . 20
4.2.4 Traction supply system change . 22
4.2.5 Re-verification . 22
4.3 Sensors . 22
4.3.1 General . 22
4.3.2 General requirements . 22
4.3.3 Voltage sensors . 24
4.3.4 Current sensors . 28
4.4 Energy Calculation Function (ECF) . 34
4.4.1 General . 34
4.4.2 General requirements . 34
4.4.3 Electrical requirements . 35
4.4.4 Accuracy requirements . 38
4.4.5 Effect of temperature on error limits . 39
4.4.6 Limits of additional error due to influence quantities . 41
4.4.7 Electromagnetic compatibility . 42
4.4.8 Data transfer from ECF to DHS . 43
5 Conformance test . 44
5.1 General . 44
5.1.1 Conformance test requirements . 44
5.1.2 Applicability . 44
5.1.3 Methodology . 44
5.2 Testing framework . 45
5.2.1 General . 45
5.2.2 Reporting . 45
5.3 Design review . 46
5.3.1 General . 46
5.3.2 Device design review . 46
5.3.3 EMF design review . 47
5.4 Type testing . 47
5.4.1 General . 47
5.4.2 Common type testing . 47
5.4.3 Sensor type test . 51

5.4.4 ECF type test . 58
5.5 Routine test . 69
5.5.1 General . 69
5.5.2 Visual Inspection . 69
5.5.3 Insulation test . 69
5.5.4 Accuracy tests . 69
Annex A (normative) Test with magnetic induction of external origin . 72
A.1 General . 72
A.2 Test method 1 . 72
A.3 Test method 2 . 72
A.4 Position of EUT . 73
Annex B (normative) EMF configurations . 74
B.1 Background. 74
B.2 General . 74
B.3 EMF with several CMFs in parallel . 74
B.4 EMF with several VMFs connected to one ECF . 75
B.5 EMF with several pairs of VMF and CMF . 75
B.6 Several EMFs in parallel . 76
B.7 One VMF or CMF connected to several ECFs . 77
B.8 EMF without VMF. 77
Annex C (informative) Expressing EMF accuracy . 78
C.1 Summary . 78
C.2 Error limits or uncertainty . 78
C.3 Presentation of error limits . 78
C.4 Uncertainty calculations . 79
C.4.1 AC active power . 79
C.4.2 Primary values . 80
C.4.3 Uncertainty in the measurement of active power (Watts) . 80
C.4.4 Relative uncertainty . 81
C.4.5 Uncertainty in the measurement of reactive power (var)  . 82
C.4.6 Relative uncertainty . 84
Annex D (informative) Re-verification and defining of its regime recommendations . 85
D.1 Re-verification . 85
D.1.1 Background . 85
D.1.2 Approaches to re-verification . 85
D.2 Defining re-verification regime recommendations . 86
D.2.1 General approach . 86
D.2.2 Testing regime . 87
Annex E (informative) Durability test . 88
E.1 Durability test . 88
E.2 Initial measurements . 88
E.3 Conditioning . 88
E.4 Intermediate measurements . 89
E.5 Final temperature ramp . 90
E.6 Final measurements and acceptance criteria . 90
E.7 Information to be given in the test report . 91
Bibliography . 92

– 4 – IEC 62888-2:2018  IEC 2018
Figure 1 – EMS functional structure and dataflow diagram . 10
Figure 2 – EMF functional block diagram . 12
Figure 3 – Example of energy index value and delta value . 15
Figure 4 – Example of maximum percentage error for a VMF of class 0,5 R and a VMF
of class 1,0 R with input signal in the range U ≤ U ≤ U . 27
min1 max2
Figure 5 – Example of maximum percentage error for a CMF class 1,0 R AC with input
signals in the range 10 % I ≤ I ≤ 120 % I , 5 % I ≤ I < 10 % I and
n n n n
1 % I ≤ I < 5 % I . 32
n n
Figure 6 – Primary current and voltage ranges . 38
Figure 7 – Example of maximum percentage error for an ECF of class 0,5 R and an
ECF of class 1,0 R with input signals in Area 1 and Area 2 . 40
Figure 8 – Test point matrix for ECF accuracy tests (type test) . 60
Figure 9 – Test point matrix for tests of ambient temperature variation and influence
quantities (type test) . 61
Figure 10 – Test circuit diagram for determining the influence on accuracy of odd
harmonics or sub-harmonics in the current circuit . 64
Figure 11 – Phase-fired waveform (shown for 50 Hz) . 64
Figure 12 – Analysis of harmonic content of phase-fired waveform (shown for 50 Hz) . 65
Figure 13 – Burst fire waveform (shown for 50 Hz) . 65
Figure 14 – Analysis of harmonics (shown for 50 Hz) . 66
Figure 15 – Test point matrix for ECF accuracy tests (routine test) . 71
Figure A.1 – Test configuration for test method 1 . 72
Figure A.2 – Test configuration for test method 2 . 73
Figure B.1 – EMF with several CMFs in parallel . 74
Figure B.2 – EMF with several VMFs connected to one ECF . 75
Figure B.3 – EMF with several pairs of VMF and CMF . 76
Figure B.4 – EMF with several ECFs . 76
Figure B.5 – One VMF connected to two ECFs . 77
Figure B.6 – EMF without VMF . 77

Table 1 – Reference conditions . 21
Table 2 – EMF percentage error limits at reference conditions . 21
Table 3 – Percentage error limits – VMF . 26
Table 4 – Maximum percentage error for a VMF including ambient temperature
variation . 26
Table 5 – Temperature coefficient for VMF . 27
Table 6 – Influence quantities for voltage sensors . 28
Table 7 – Percentage error limits – AC CMF . 30
Table 8 – Percentage error limits – DC CMF . 31
Table 9 – Maximum percentage error for a CMF including ambient temperature
variation . 31
Table 10 – Temperature coefficient for CMF . 32
Table 11 – Percentage error limits with harmonics – AC current sensor . 33
Table 12 – Influence quantities for current sensors . 33
Table 13 – Variations due to short-time overcurrents . 37
Table 14 – Variations due to self-heating . 37

Table 15 – ECF percentage error limits for active energy . 38
Table 16 – Maximum percentage error for an ECF including ambient temperature
variation . 39
Table 17 – Temperature coefficient for the ECF . 40
Table 18 – Influence quantities for the ECF . 41
Table 19 – Test current for harmonics . 54

– 6 – IEC 62888-2:2018  IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RAILWAY APPLICATIONS –
ENERGY MEASUREMENT ON BOARD TRAINS –

Part 2: Energy measurement
FOREWORD
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International Standard IEC 62888-2 has been prepared by IEC technical committee 9:
Electrical equipment and systems for railways.
This standard is based on EN 50463.
The text of this International Standard is based on the following documents:
FDIS Report on voting
9/2321/FDIS 9/2332/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts in the IEC 62888 series, published under the general title Railway
applications – Energy measurement on board trains, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document 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.
– 8 – IEC 62888-2:2018  IEC 2018
INTRODUCTION
Three levels are introduced for categorizing EMS as described in IEC 62888-1:2018, 4.1.
This is Part 2 of the IEC 62888 series, which consists of the following parts, under the
common title Railway applications – Energy measurement on board trains:
Part 1: General
Part 2: Energy measurement
Part 3: Data handling
Part 4: Communication
Part 5: Conformance test
Part 6: Requirements for purposes other than billing
This series of International Standards follows the functional guidelines description in Annex A,
“Principles of conformity assessment”, of ISO/IEC 17000:2004 tailored to the Energy
Measurement System (EMS).
The Energy Measurement System (EMS) provides measurement and data suitable for
applications such as energy management, energy saving, billing and others.
This series of International Standards uses the functional approach to describe the EMS.
These functions are implemented in one or more physical devices. The user of this series of
standards is free to choose the physical implementation arrangements.
Structure and main contents of the IEC 62888 series
This series of International Standards is divided into six parts. The titles and brief descriptions
of each part are given below:
IEC 62888-1 – General
The scope of IEC 62888-1 is the Energy Measurement System (EMS).
IEC 62888-1 provides system level requirements for the complete EMS and common
requirements for all devices implementing one or more functions of the EMS.
IEC 62888-2 – Energy measurement
The scope of IEC 62888-2 is the Energy Measurement Function (EMF).
The EMF provides measurement of the consumed and regenerated active energy of a traction
unit. If the traction unit is designed for use on AC traction supply systems, the EMF also
provides measurement of reactive energy. The EMF provides the measured quantities via an
interface to the Data Handling System.
The EMF consists of the three functions: Voltage Measurement Function, Current
Measurement Function and Energy Calculation Function. For each of these functions,
accuracy classes are specified and associated reference conditions are defined. This part
also defines all specific requirements for all functions of the EMF.
The Voltage Measurement Function measures the voltage of the contact line (CL) system and
the Current Measurement Function measures the current taken from and returned to the CL
system. These functions provide signal inputs to the Energy Calculation Function.

The Energy Calculation Function inputs the signals from the Current and Voltage
Measurement Functions and calculates a set of values representing the consumed and
regenerated energies. These values are transferred to the Data Handling System and are
used in the creation of Compiled Energy Measured Data.
All relevant metrological aspects are covered in this part of IEC 62888.
IEC 62888-2 also defines the conformance test of the EMF.
IEC 62888-3 – Data handling
The scope of IEC 62888-3 is the Data Handling System (DHS).
The on board DHS receives, produces and stores data, ready for transmission to any
authorised receiver of data on board or on ground. The main goal of the DHS is to produce
Compiled Energy Measured Data and transfer it to an on-ground Data Collection Service
(DCS). The DHS can support other functionality on board or on-ground with data, as long as
this does not conflict with the main goal.
IEC 62888-3 also defines the conformance test of the DHS.
IEC 62888-4 – Communication
The scope of IEC 62888-4 is the communication services.
This part of IEC 62888 gives requirements and guidance regarding the data communication
between the functions implemented within EMS as well as between such functions and other
on board units where data are exchanged using a communications protocol stack over a
dedicated physical interface or a shared network.
It includes the on board to ground communication service and covers the requirements
necessary to support data transfer between DHS and DCS.
IEC 62888-4 also defines the conformance test of the communications services.
IEC 62888-5 – Conformance test
The scope of IEC 62888-5 is the conformance test procedures for the EMS.
IEC 62888-5 also covers re-verification procedures and conformance test in the event of the
replacement of a device of the EMS.
IEC 62888-6 – Requirements for purposes other than billing
The scope of IEC 62888-6 is to specify the requirements for EMS to be used for
benchmarking, daily energy consumption monitoring, technical research and development.
This part provides the requirements for monitoring consumed energy on-board in daily
services in an easy way and the measured data are applicable for general purposes in
industry such as energy management, energy saving, etc. However, this part is not applicable
for billing purposes.
– 10 – IEC 62888-2:2018  IEC 2018
EMS functional structure and dataflow
Figure 1 illustrates the functional structure of the EMS, the main sub-functions and the
structure of the dataflow and is informative only. Only the main interfaces required by this
standard are displayed by arrows.
Since the communication function is distributed throughout the EMS, it has been omitted for
clarity. Not all interfaces are shown.
Settlement
Other Systems
Time Reference Source
System
Location Reference Source
Data Storage Function
Current Measurement Function
Voltage Measurement Function
Data compilation Function
Energy Calculation Function Data
Collection
Service
Energy Measurement Function
Data Handling System
(DCS)
(EMF)
(DHS)
IEC 62888-2 (Energy Measuring) IEC 62888-3 (Data Handling)
Energy Measurement System (EMS)
Other
Systems
IEC 62888-1 (General), IEC 62888-4 (Communication), IEC 62888-5 (Conformity)

Assessment), IEC 62888-6 (Purposes other than billing)
On-board (Traction Unit)
On-ground
IEC
Figure 1 – EMS functional structure and dataflow diagram

RAILWAY APPLICATIONS –
ENERGY MEASUREMENT ON BOARD TRAINS –

Part 2: Energy measurement
1 Scope
This part of IEC 62888 specifies the requirements applicable to the Energy Measurement
Function (EMF) of an Energy Measurement System (EMS) for use on board traction units for
measurement of energy supplied directly from/to the Contact Line system.
This document also gives requirements for the Current Measurement Function (e.g. current
sensor), the Voltage Measurement Function (e.g. voltage sensor) and the Energy Calculation
Function (e.g. energy meter).
The conformance test arrangements for the Voltage Measurement Function, Current
Measurement Function, the Energy Calculation Function and a complete Energy
Measurement Function are also specified in this document.
This document has been developed taking into account that in some applications the EMF
may be subjected to metrological assessment. All relevant metrological aspects are covered
in this part and they are applicable to EMS Level 1.
Specific requirements for EMS Level 2 and Level 3 are specified in IEC 62888-6.
Figure 2 shows the flow between the functional blocks of the EMF. Only connections between
the functional blocks required by this document are displayed.

– 12 – IEC 62888-2:2018  IEC 2018
Energy Measurement Function
(EMF)
Current Voltage
Measurement Measurement
Function (CMF) Function (VMF)
(current sensor) (voltage sensor)
Current signal
Voltage signal
Calculation of
∆ t
active and
reactive energy
Transmission of
energy data
Energy Calculation Function
(ECF)
Active and reactive
energy index values
and/or energy delta values
Data Handling
System (DHS)
IEC
Figure 2 – EMF functional block diagram
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 60028:1925, International standard of resistance for copper
IEC 60044-8:2002, Instrument transformers – Part 8: Electronic current transformers
IEC 60068-2-1:2007, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
IEC 60077-4:2003, Railway applications – Electric equipment for rolling stock – Part 4:
Electrotechnical components – Rules for AC circuit-breakers

IEC 60085:2007, Electrical insulation – Thermal evaluation and designation
IEC 60121:1960, Recommendation for commercial annealed aluminium electrical conductor
wire
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1999
IEC 60529:1989/AMD2:2013
IEC 60571:2012, Railway applications – Electronic equipment used on rolling stock
IEC 60850:2014, Railway applications – Supply voltages of traction systems
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-3:2006/AMD1:2007
IEC 61000-4-3:2006/AMD2:2010
IEC 61000-4-4:2012, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5:2014, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
IEC 61000-4-6:2013, Electromagnetic compatibility (EMC) – Part 4-6: Testing and
measurement techniques – Immunity to conducted disturbances, induced by radio-frequency
fields
IEC 61373:2010, Railway applications – Rolling stock equipment – Shock and vibration tests
IEC 61869 (all parts), Instrument transformers
IEC 61869-1, Instrument transformers – Part 1: General requirements
IEC 61869-2:2012, Instrument transformers – Part 2: Additional requirements for current
transformers
IEC 61992-1:2006, Railway applications – Fixed installations – D.C. switchgear – Part 1:
General
IEC 62236-1:2008, Railway applications – Electromagnetic compatibility – Part 1: General
IEC 62236-3-2:2008, Railway applications – Electromagnetic compatibility – Part 3-2: Rolling
stock – Apparatus
IEC 62497-1, Railway applications – Insulation coordination – Part 1: Basic requirements –
Clearances and creepage distances for all electrical and electronic equipment
IEC 62498-1:2010, Railway applications – Environmental conditions for equipment – Part 1:
Equipment on board rolling stock

– 14 – IEC 62888-2:2018  IEC 2018
IEC 62313:2009, Railway applications – Power supply and rolling stock – Technical criteria for
the coordination between power supply (substation) and rolling stock to achieve
interoperability
IEC 62888-1:2018, Railway applications – Energy measurement on board trains – Part 1:
General
IEC 62888-3:2018, Railway applications – Energy measurement on board trains – Part 3:
Data handling
IEC 62888-4:2018, Railway applications – Energy measurement on board trains – Part 4:
Communication
IEC 62888-5:2018, Railway applications – Energy measurement on board trains – Part 5:
Conformance test
3 Terms, definitions, abbreviated terms and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62888-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
accuracy class
designation that identifies a set of error limits for measured quantities under reference
conditions and the additional percentage errors due to influence quantities
Note 1 to entry: An individual accuracy class is associated with each metrological function of the EMF.
Note 2 to entry: The suffix “R” is used to differentiate classes according to this standard from other technical
standards.
3.1.2
consumed active energy
active energy taken from the contact line by the traction unit on which the EMF is installed
3.1.3
consumed reactive energy
reactive energy taken from the contact line by the traction unit on which the EMF is installed
3.1.4
electronic sensor
device in which electronic circuits are used to process a measured signal
Note 1 to entry: Electronic circuits for processing the measurement signal include items such as analogue to
digital converters, signal amplifiers, etc.
3.1.5
energy delta value
energy consumed and/or regenerated during a time period
Note 1 to entry: See Figure 3 for an example.

energy index value: 2350 2360 2372 2379 2393 2404
12 7 14 11
energy delta value:
Timeline::
10:35 10:40 10:45 10:50 10:55 11:00

IEC
Figure 3 – Example of energy index value and delta value
3.1.6
energy index value
total accumulated energy consumption and/or energy regeneration at the end of a time period
Note 1 to entry: See Figure 3 for an example.
3.1.7
flag
code indicating information relevant to the functioning of the EMS
Note 1 to entry: Examples include data quality, operational status, etc.
3.1.8
index value overrun
return to zero of the index value after reaching the maximum value allowed by the register
3.1.9
influence quantity
external condition which affects metrological performance
3.1.10
k-factor
multiplicand necessary to convert a secondary value into a primary value
Note 1 to entry: Each Voltage Measurement Function and/or Current Measurement Function can have a specific
k-factor. If the k-factor is applied to Energy Data, this factor is the product of the k-factors of the Voltage
Measurement Function and/or Current Measurement Function used.
3.1.11
percentage error
−
Q Q
M T
ε = ×100
Q
T
where
Q is the measured quantity;
M
Q is the true quantity
T
Note 1 to entry: Since the true quantity cannot be determined, it is approximated by a quantity with a stated
uncertainty that can be traced to standards agreed upon between supplier and purchaser or to national standards.
3.1.12
phase influence function
function of the real or apparent phase angle between a measured voltage and a measured
current
Note 1 to entry: Phase influence function expressed as a power factor refers to measurements of real and
apparent powers and energies, while sin φ refers to reactive powers and energies.
Note 2 to entry: For DC measurements the requirements for a phase influence function of 1 need to be used.

– 16 – IEC 62888-2:2018  IEC 2018
3.1.13
Power Factor
PF
under periodic conditions, ratio of the absolute value of the active power P to the apparent
power S
Note 1 to entry: Under sinusoidal conditions, the power factor is the absolute value of the active factor.
[SOURCE: IEC 60050-131:2002, 131-11-46]
3.1.14
primary value
value referred to the measuring inputs of an EMF
3.1.15
rated continuous thermal current
I
CMF,cth
value of current which can be permitted to flow continuously into the primary input of a current
sensor
3.1.16
ra
...