IEC TR 63519:2024

IEC TR 63519 ®
Edition 1.0 2024-08
TECHNICAL
REPORT
Aspects and understanding of measurement uncertainty – Background
information on measurement uncertainty based on the example of IEC TC 85
(Measuring equipment for electrical and electromagnetic quantities)

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IEC TR 63519 ®
Edition 1.0 2024-08
TECHNICAL
REPORT
Aspects and understanding of measurement uncertainty – Background

information on measurement uncertainty based on the example of IEC TC 85

(Measuring equipment for electrical and electromagnetic quantities)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.220.20  ISBN 978-2-8322-9420-8

– 2 – IEC TR 63519:2024 © IEC 2024
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Role of the measurement uncertainty. 6
4.1 General . 6
4.2 Compatibility . 8
4.3 Probability of false acceptance or probability of false rejection . 9
4.4 Metrological traceability . 10
4.5 Improvement (influence quantities) . 11
4.6 Conclusions . 11
5 Example: Insulation resistance IEC 61557-2:2019 . 11
5.1 Concept (IEC 61557-1:2019) . 11
5.2 Calculation . 12
5.3 Conclusions . 13
6 Further examples . 14
Bibliography . 15

Figure 1 – Measurement of a voltage of 1 V with a resolution of 1 mV on a digital
display . 7
Figure 2 – Rectangular (uniform) distribution for the resolution when measuring a
voltage of 1 V with a resolution of 1 mV on a digital display . 7
Figure 3 – Value and assigned measurement uncertainty (MU) together with its
probability density function (PDF) . 8
Figure 4 – Compatibility of two measured values with or without measurement
uncertainty . 8
Figure 5 – Probability of compatibility of two values . 9
Figure 6 – PFA, given by 1 − P(A), for the in tolerance decision when comparing a
value to a limit . 10
Figure 7 – Pyramid of metrological traceability . 10

Table 1 – Role of the measurement uncertainty for different stakeholders . 11
Table 2 – Example calculation for the percentage operating uncertainty for the fiducial
value F = 8 MΩ . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ASPECTS AND UNDERSTANDING OF MEASUREMENT UNCERTAINTY –

Background information on measurement uncertainty based on the
example of IEC TC 85 (Measuring equipment for electrical and
electromagnetic quantities)
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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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IEC TR 63519 has been prepared by IEC technical committee TC 85: Measuring equipment for
electrical and electromagnetic quantities. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
85/918/DTR 85/927/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
– 4 – IEC TR 63519:2024 © IEC 2024
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
ASPECTS AND UNDERSTANDING OF MEASUREMENT UNCERTAINTY –

Background information on measurement uncertainty based on the
example of IEC TC 85 (Measuring equipment for electrical and
electromagnetic quantities)
1 Scope
This document provides information on terminology and general concepts in the determination
of measurement uncertainties (MU). It focuses on application aspects based on the example of
IEC TC 85 (Measuring equipment for electrical and electromagnetic quantities) and shows the
opportunities and implications for further use of measurement uncertainties.
Measurement uncertainties are relevant for metrological compatibility and metrological
traceability. Therefore, information on the role of measurement uncertainty in decisions or
conformity assessments is given.
References to documents, standards and guidelines are made but only key results will be stated.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
probability distribution
function giving the probability that a random variable takes any given value or belongs to a
given set of values
[SOURCE: IEC 60050-103:2009, 103-08-07]
3.2
distribution function
function f of the argument x giving the probability f(x) that the value ξ of a random variable be
less than or equal to the value x, i.e. the probability that ξ ≤ x
[SOURCE: IEC 60050-103:2009, 103-08-08]

– 6 – IEC TR 63519:2024 © IEC 2024
3.3
probability density
probability density function
PDF
for the distribution function f of the argument x, derivative df(x) / dx
[SOURCE: IEC 60050-103:2009, 103-08-09]
3.4
calibration
set of operations which establishes, by reference to standards, the relationship which exists,
under specified conditions, between an indication and a result of a measurement
Note 1 to entry: This term is based on the "uncertainty" approach.
Note 2 to entry: The relationship between the indications and the results of measurement can be expressed, in
principle, by a calibration diagram.
[SOURCE: IEC 60050-300:2001, 311-01-09]
3.5
metrological compatibility of measurement results
metrological compatibility
property of a set of measurement results for a specified measurand, such that the absolute
value of the difference of any pair of measured quantity values from two different measurement
results is smaller than some chosen multiple of the standard measurement uncertainty of that
difference
Note 1 to entry: Metrological compatibility of measurement results replaces the traditional concept of 'staying within
the error', as it represents the criterion for deciding whether two measurement results refer to the same measurand
or not. If in a set of measurements of a measurand, thought to be constant, a measurement result is not compatible
with the others, either the measurement was not correct (e.g. its measurement uncertainty was assessed as being
too small) or the measured quantity changed between measurements.
Note 2 to entry: Correlation between the measurements influences metrological compatibility of measurement
results. If the measurements are completely uncorrelated, the standard measurement uncertainty of their difference
is equal to the root mean square sum of their standard measurement uncertainties, while it is lower for positive
covariance or higher for negative covariance.
[SOURCE: ISO/IEC Guide 99:2007, 2.47]
4 Role of the measurement uncertainty
4.1 General
Measurements are subject to influences. Although a single value is measured, the result is an
interval of possible values. The measurement uncertainty comes into place in order to define
the limits of this interval and give a number to this imperfection.
EXAMPLE Measurement of a voltage of 1 V with a resolution of 1 mV on a digital display. Reading a value of
1,000 V would lead to an interval from 0,999 50 V to 1,000 49 V if only the resolution is considered (see Figure 1).
The reading of 1,000 V is in the middle of the interval with a width given by the resolution. It is assumed that the
resolution of the display corresponds to the last significant digit of the device.

Figure 1 – Measurement of a voltage of 1 V with a resolution of 1 mV on a digital display
When it comes to the determination of the measurement uncertainty, the Guide to the
expression of uncertainty in measurement (GUM, [IS
...