SIST EN IEC 60060-1:2025

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN 60060-1:2011
Visokonapetostne preskusne tehnike - 1. del: Splošne definicije in preskusne
zahteve
High-voltage test techniques - Part 1: General definitions and test requirements
Hochspannungs-Prüftechnik - Teil 1: Allgemeine Begriffe und Prüfbedingungen
Technique des essais à haute tension - Partie 1: Définitions et exigences générales
Ta slovenski standard je istoveten z: EN IEC 60060-1:2025
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
19.080 Električno in elektronsko Electrical and electronic
preskušanje testing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60060-1

NORME EUROPÉENNE
EUROPÄISCHE NORM June 2025
ICS 17.220.20 Supersedes EN 60060-1:2010
English Version
High-voltage test techniques - Part 1: General terminology and
test requirements
(IEC 60060-1:2025)
Techniques d'essais à haute tension - Partie 1: Hochspannungs-Prüftechnik - Teil 1: Allgemeine Begriffe
Terminologie générale et exigences d'essai und Prüfbedingungen
(IEC 60060-1:2025) (IEC 60060-1:2025)
This European Standard was approved by CENELEC on 2025-05-22. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60060-1:2025 E

European foreword
The text of document 42/444/FDIS, future edition 4 of IEC 60060-1, prepared by TC 42 "High-voltage
and high-current test techniques" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 60060-1:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-06-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-06-30
document have to be withdrawn
This document supersedes EN 60060-1:2010 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60060-1:2025 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 standard indicated:
IEC 60270 NOTE Approved as EN 60270
IEC 60507 NOTE Approved as EN 60507
IEC 60060-3 NOTE Approved as EN 60060-3
IEC 60071-1 NOTE Approved as EN IEC 60071-1
IEC 60071-2 NOTE Approved as EN IEC 60071-2
IEC 62271-1 NOTE Approved as EN 62271-1
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60060-2 - High-voltage test techniques - Part 2: EN IEC 60060-2 -
Measuring systems
IEC 61083-1 - Instruments and software used for EN 61083-1 -
measurement in high-voltage impulse tests
- Part 1: Requirements for instruments
IEC 61083-2 - Instruments and software used for EN 61083-2 -
measurement in high-voltage and high-
current tests - Part 2: Requirements for
software for tests with impulse voltages
and currents
IEC 62475 - High-current test techniques - Definitions EN 62475 -
and requirements for test currents and
measuring systems
IEC 60060-1 ®
Edition 4.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
High-voltage test techniques –

Part 1: General terminology and test requirements

Techniques d'essais à haute tension –

Partie 1: Terminologie générale et exigences d'essai

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20  ISBN 978-2-8327-0328-1

– 2 – IEC 60060-1:2025 © IEC 2025
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
3.1 Terms related to characteristics of discharges . 9
3.2 Terms related to characteristics of the test voltage . 9
3.3 Terms related to tolerance and uncertainty . 10
3.4 Terms related to statistical characteristics of disruptive discharge voltage
values . 10
3.5 Terms related to classification of insulation in test objects . 12
3.6 Definitions for direct voltage tests . 13
3.7 Terms for alternating voltage tests . 13
3.8 Terms for lightning impulse voltage tests . 14
3.9 Terms for switching impulse voltage tests . 22
3.10 Terms for combined voltage tests . 24
3.11 Terms for composite voltage tests . 26
4 General requirements . 29
4.1 General requirements for test procedures . 29
4.2 Arrangement of the test object in dry tests . 29
4.3 Atmospheric corrections in dry tests. 30
4.3.1 Standard reference atmosphere . 30
4.3.2 Atmospheric correction factors for air gaps . 30
4.3.3 Application of correction factors . 30
4.3.4 Correction factor components . 31
4.3.5 Measurement of atmospheric parameters . 35
4.3.6 Conflicting requirements for testing internal and external insulation . 36
4.4 Wet tests . 37
4.4.1 Wet test procedure . 37
4.4.2 Atmospheric corrections for wet tests . 38
4.5 Artificial pollution tests . 38
5 Tests with direct voltage . 39
5.1 Test voltage . 39
5.1.1 Requirements for the test voltage . 39
5.1.2 Generation of the test voltage . 39
5.1.3 Measurement of the test voltage . 39
5.1.4 Measurement of the test current . 39
5.2 Test procedures . 40
5.2.1 Withstand voltage tests . 40
5.2.2 Disruptive discharge voltage tests . 40
5.2.3 Assured disruptive discharge voltage tests . 41
6 Tests with alternating voltage . 41
6.1 Test voltage . 41
6.1.1 Requirements for the test voltage . 41
6.1.2 Generation of the test voltage . 42
6.1.3 Measurement of the test voltage . 43
6.1.4 Measurement of the test current . 43
6.2 Test procedures . 43

IEC 60060-1:2025 © IEC 2025 – 3 –
6.2.1 Withstand voltage tests . 43
6.2.2 Disruptive discharge voltage tests . 44
6.2.3 Assured disruptive discharge voltage tests . 44
7 Tests with lightning impulse voltage. 44
7.1 Test voltage . 44
7.1.1 Requirements for test voltages . 44
7.1.2 Generation of the test voltage . 45
7.1.3 Measurement of the test voltage and determination of impulse shape . 45
7.1.4 Measurement of current during tests with impulse voltages . 46
7.2 Test procedures . 46
7.2.1 Withstand voltage tests . 46
7.2.2 Assured disruptive discharge voltage tests . 47
8 Tests with switching impulse voltage . 47
8.1 Test voltage . 47
8.1.1 Requirements for test voltages . 47
8.1.2 Generation of the test voltage . 48
8.1.3 Measurement of test voltage and determination of impulse shape . 48
8.1.4 Measurement of current during tests with impulse voltages . 48
8.2 Test procedures . 48
9 Tests with combined voltages . 49
9.1 General . 49
9.2 Test voltage . 49
9.2.1 Requirements for the test voltage . 49
9.2.2 Generation of test voltages . 49
9.2.3 Measurement of the test voltage . 50
9.3 Test procedures . 50
10 Tests with composite voltages . 50
10.1 General . 50
10.2 Test voltage . 50
10.2.1 Requirements for the test voltage . 50
10.2.2 Generation of test voltages . 51
10.2.3 Measurement of the test voltage . 51
10.3 Test procedures . 51
Annex A (informative) Statistical treatment of test results . 52
A.1 Classification of tests . 52
A.1.1 General . 52
A.1.2 Class 1: Multiple-level tests (Figure A.1) . 52
A.1.3 Class 2: Up-and-down tests (Figure A.2) . 52
A.1.4 Class 3: Progressive stress tests (Figure A.3) . 53
A.2 Statistical behaviour of disruptive discharge. 53
A.2.1 General . 53
A.2.2 Confidence limits . 53
A.3 Analysis of test results . 54
A.3.1 General . 54
A.3.2 Treatment of results from Class 1 tests . 57
A.3.3 Treatment of results from Class 2 tests . 58
A.3.4 Treatment of results from Class 3 tests . 59
A.4 Application of maximum likelihood methods . 60

– 4 – IEC 60060-1:2025 © IEC 2025
Annex B (normative) Procedures for calculation of parameters of standard lightning
impulse voltages without or with superimposed overshoot or oscillations . 62
B.1 General remarks . 62
B.2 Basis of the procedures . 62
B.3 Procedure for evaluation of parameters of full lightning impulses . 62
B.4 Procedure for evaluation of parameters of tail chopped lightning impulses . 65
Annex C (informative) Procedure for manual calculation from graphical waveforms . 67
Annex D (informative) Guidance for implementing software for evaluation of lightning
impulse voltage parameters . 68
D.1 Guidance for implementing base curve fitting . 68
D.2 Example of a digital filter for implementation of the test voltage function . 68
Annex E (informative) Iterative calculation method in the converse procedure for the
determination of the atmospheric correction factor . 70
E.1 Introductory remarks . 70
E.2 Change of atmospheric pressure with altitude . 70
E.3 Sensitivity of K to U . 71
t 50
E.4 Calculation with the iterative calculation procedure . 72
E.5 Comment . 77
Annex F (informative) Front time and time to peak of switching impulse voltage . 78
F.1 Front time of switching impulse . 78
F.2 Time to peak for standard switching impulse voltage . 78
F.3 Time to peak and front time for standard switching impulse voltage . 78
F.4 Non-standard switching impulse voltage . 79
Bibliography . 80

Figure 1 – Full lightning impulse voltage . 14
Figure 2 – Test voltage function . 16
Figure 3 – Full impulse voltage time parameters . 17
Figure 4 – Voltage time interval . 18
Figure 5 – Voltage integral . 19
Figure 6 – Lightning impulse voltage chopped on the front . 20
Figure 7 – Lightning impulse voltage chopped on the tail . 20
Figure 8 – Linearly rising front-chopped impulse . 21
Figure 9 – Voltage versus time curve for impulses of constant prospective shape . 22
Figure 10 – Switching impulse voltage . 23
Figure 11 – Circuit for a combined voltage test . 24
Figure 12 – Schematic example for combined voltage (AC + positive impulse) between
two HV terminals . 25
Figure 13 – Examples of time delay Δt . 26
Figure 14 – Circuit for a composite voltage test . 27
Figure 15 – Schematic example for composite voltage (AC and positive impulse)
between one HV terminal and earth . 28
Figure 16 – Examples of time delay Δt . 28
Figure 17 – Recommended minimum clearance D of extraneous live or earthed objects
to the energized electrode of a test object, during an AC or positive switching impulse
test at the maximum voltage U applied during the test . 29

IEC 60060-1:2025 © IEC 2025 – 5 –
Figure 18 – k as a function of the ratio of the absolute humidity h to the relative air
density δ (see 4.3.4.2 for limits of applicability) . 33
Figure 19 – Values of exponents m (a) and w (b) for humidity correction as a function
of parameter g . 34
Figure 20 – Absolute humidity of air as a function of dry and wet-bulb thermometer
readings. 36
Figure A.1 – Example of a multiple-level (Class 1) test . 55
Figure A.2 – Examples of decreasing and increasing up-and-down (Class 2) tests for
determination of 10 % and 90 % disruptive discharge probabilities respectively . 56
Figure A.3 – Examples of progressive stress (Class 3) tests . 57
Figure B.1 – Recorded and base curves showing overshoot and residual curve . 63
Figure B.2 – Test voltage curve (addition of base curve and filtered residual curve) . 63
Figure B.3 – Recorded and test voltage curves . 64
Figure E.1 – Atmospheric pressure as a function of altitude . 71

Table 1 – Values of exponents, m for air density correction and w for humidity
correction, as a function of the parameter g . 34
Table 2 – Precipitation conditions for standard procedure . 38
Table A.1 – Discharge probabilities in up-and-down testing . 59
Table E.1 – Altitudes and air pressure of some locations . 71
Table E.2 – Initial K and its sensitivity coefficients with respect to U for the example
t 50
of the standard phase-to-earth AC test voltage of 395 kV . 72
Table E.3 – Initial and converged K values for the example of the standard phase-to-
t
earth AC test voltage of 395 kV. 77

– 6 – IEC 60060-1:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-VOLTAGE TEST TECHNIQUES –

Part 1: General terminology and test requirements

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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60060-1 has been prepared by IEC technical committee 42: High-voltage and high-current
test techniques. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2010. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The general layout and text have been updated and improved to make the standard easier
to use, particularly the clauses for combined and composite test voltages.
b) The positive tolerance of the front time of lightning impulse voltage has been extended for
U > 800 kV to 100 % (= 2,4 µs).
m
IEC 60060-1:2025 © IEC 2025 – 7 –
c) For switching impulse voltage, a front time has been introduced, similar to lightning impulse
voltage and with the new front time the standard switching impulse is defined as
170/2 500 µs.
d) The requirements for precipitations in wet tests have been adjusted depending on U .
m
e) A new Annex C, "Procedure for manual calculation from graphical waveforms" has been
incorporated.
f) Examples of software packages have been removed in Annex D, "Guidance for
implementing software for evaluation of lightning impulse voltage parameters".
g) The annex relating to the "Background to the introduction of the test voltage factor for
evaluation of impulses with overshoot" has been deleted.
h) A new informative Annex F, "New definition of the front time of switching impulse voltage"
has been incorporated.
The text of this International Standard is based on the following documents:
Draft Report on voting
42/444/FDIS 42/454A/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard 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.
A list of all the parts in the IEC 60060 series, published under the general title High-voltage test
techniques, 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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 8 – IEC 60060-1:2025 © IEC 2025
HIGH-VOLTAGE TEST TECHNIQUES –

Part 1: General terminology and test requirements

1 Scope
This part of IEC 60060 is applicable to:
– dielectric tests with direct voltage;
– dielectric tests with alternating voltage;
– dielectric tests with impulse voltage;
– dielectric tests with combinations of the above.
This document is applicable to tests on equipment having its highest voltage for equipment U
m
above 1,0 kV AC and 1,5 kV DC.
NOTE 1 Alternative test procedures can be required to obtain reproducible and significant results. The choice of a
suitable test procedure is considered by the relevant Technical Committee.
NOTE 2 For voltages U above 800 kV it is possible that some specified procedures, tolerances and uncertainties
m
will not be achievable.
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 60060-2, High-voltage test techniques – Part 2: Measuring systems
IEC 61083-1, Instruments and software used for measurements in high-voltage and high-
current tests – Part 1: Requirements for instruments for impulse tests
IEC 61083-2, Instruments and software used for measurement in high-voltage and high-current
tests – Part 2: Requirements for software for tests with impulse voltages and currents
IEC 62475, High-current test techniques – Definitions and requirements for test currents and
measuring systems
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

IEC 60060-1:2025 © IEC 2025 – 9 –
3.1 Terms related to characteristics of discharges
3.1.1
disruptive discharge
phenomenon associated with the failure of insulation under electrical stress which includes a
collapse of voltage and the passage of current
Note 1 to entry: The term applies to electric breakdown in solid, liquid and gaseous dielectrics and combination of
these.
Note 2 to entry: A disruptive discharge in a solid dielectric produces permanent loss of dielectric strength; in a liquid
or gaseous dielectric the loss of dielectric strength can be temporary.
[SOURCE: IEC 60050-614:2016, 614-03-16, modified – In Note 2 to entry, "the loss may be
temporary only" has been replaced with "the loss of dielectric strength can be temporary".]
3.1.2
sparkover
disruptive discharge in a gaseous or liquid insulating material
[SOURCE: IEC 60050-212:2010, 212-11-48]
3.1.3
flashover
electric breakdown between conductors in a gas or a liquid or in vacuum, at least partly along
the surface of solid insulation
[SOURCE: IEC 60050-212:2010, 212-11-47]
3.1.4
puncture
disruptive discharge occurring through a solid insulation material, producing a path of
permanent damage
Note 1 to entry: The term puncture is also used as a synonym for electric breakdown in solids.
[SOURCE: IEC 60050-212:2010, 212-11-49]
3.1.5
disruptive discharge voltage value
value of the test voltage causing disruptive discharge
Note 1 to entry: The value is specified, for the various tests, in the relevant clauses of this document.
3.1.6
non-disruptive discharge
discharge between intermediate electrodes or conductors where the test voltage does not
collapse to zero
Note 1 to entry: Such an event is not considered as a disruptive discharge unless so specified by the relevant
Technical Committee.
Note 2 to entry: Some non-disruptive discharges are termed "partial discharges" and are dealt with in IEC 60270.
3.2 Terms related to characteristics of the test voltage
3.2.1
prospective shape
shape which would have been obtained if no disruptive discharge had occurred

– 10 – IEC 60060-1:2025 © IEC 2025
3.2.2
withstand voltage
specified prospective voltage value which characterizes the insulation of the object with regard
to a withstand test
Note 1 to entry: Withstand voltages which apply to external insulation only are referred to standard reference
atmospheric conditions (see 4.3.1) unless otherwise specified.
3.2.3
assured disruptive discharge voltage
specified prospective voltage value which characterizes its performance with regard to a
disruptive discharge test
3.2.4
voltage dip
sudden reduction of the voltage at a point in an electrical system followed by voltage recovery
after a short period of time from a few cycles to a few seconds
[SOURCE: IEC 60050-161:1990, 161-08-10]
3.3 Terms related to tolerance and uncertainty
3.3.1
tolerance
permitted difference between the measured value and the specified value
Note 1 to entry: The tolerance shall be distinguished from the uncertainty of a measurement.
Note 2 to entry: A pass/fail decision is based on the measured value, without consideration given to the range of
values enclosed by the measurement uncertainty.
3.3.2
uncertainty
parameter, associated with the result of a measurement, that characterizes
the dispersion of the values that could reasonably be attributed to the measurand
Note 1 to entry: In this document, all uncertainty values are specified at a coverage probability of 95 %.
Note 2 to entry: Uncertainty is positive and given without sign.
Note 3 to entry: Uncertainty of measurement should not be confused with the tolerance of a specified test value or
parameter.
[SOURCE: IEC 60050-311:2001, 311-01-02, modified – The three Notes have been replaced
with new three Notes to entry.]
3.4 Terms related to statistical characteristics of disruptive discharge voltage values
3.4.1
disruptive discharge probability
p
probability that an application of a certain prospective voltage value of a given shape will cause
disruptive discharge on the test object
Note 1 to entry: The parameter p is usually expressed as a percentage or a fraction.

IEC 60060-1:2025 © IEC 2025 – 11 –
3.4.2
withstand probability
q
probability that an application of a certain prospective voltage value of a given shape does not
cause a disruptive discharge on the test object
Note 1 to entry: If the disruptive discharge probability is p, the withstand probability q is (1 – p).
3.4.3
p % disruptive discharge voltage
U
p
prospective voltage value which has p % probability of producing a disruptive discharge on the
test object
Note 1 to entry: Mathematically the p % disruptive discharge voltage is the quantile of the order p (or p quantile) of
the breakdown voltage.
Note 2 to entry: U is called the "statistical withstand voltage" and U is called the "statistical assured disruptive
10 90
discharge voltage".
3.4.4
50 % disruptive discharge voltage
U
prospective voltage value which has a 50 % probability of producing a disruptive discharge on
the test object
3.4.5
arithmetic mean value of the disruptive discharge voltage
U
a
evaluation of the arithmetic mean value of the disruptive discharge voltage U as given in
a
Equation (1)
n
UU= (1)
∑
a i
n
i=1
where
U is the measured disruptive discharge voltage, and
i
n is the number of discharges.
Note 1 to entry: For symmetric distributions U is identical to U
a 50
– 12 – IEC 60060-1:2025 © IEC 2025
3.4.6
standard deviation of the disruptive voltage
s
measure of the dispersion of the disruptive discharge voltage estimated by
n
s UU− (2)
( )
∑ i a
n−1
i=1
where
th
U is the i measured disruptive discharge voltage,
i
U is the arithmetic mean of the disruptive discharge voltages,
a
n is the number of observations (discharges).
Note 1 to entry: The standard deviation of the disruptive voltage can also be evaluated by the difference between
the 50 % and 16 % disruptive discharge voltages (or between the 84 % and 50 % disruptive discharge voltages). It
is often expressed in per unit or percentage value referred to the 50 % disruptive discharge voltage.
Note 2 to entry: For successive disruptive discharge tests the standard deviation s is defined by the formula. For
multiple level and up-and-down tests, it is defined by the difference of the quantiles. The methods are equivalent
because, between p = 16 % and p = 84 % all distribution functions are nearly identical.
3.5 Terms related to classification of insulation in test objects
3.5.1
external insulation
air insulation and the exposed surfaces of solid insulation of the equipment, which are subject
both to dielectric stresses and to the direct effects of atmospheric and other environmental
conditions
Note 1 to entry: Examples of environmental conditions are pollution and humidity.
3.5.2
internal insulation
internal solid, liquid or gaseous elements of the insulation of equipment protected from the
direct effects of external conditions such as pollution and humidity
3.5.3
self-restoring insulation
insulation which completely recovers its insulating properties within a short time interval after a
disruptive discharge
[SOURCE: IEC 60050-614:2016, 614-03-04]
3.5.4
non-self-restoring insulation
insulation which loses its insulating properties, or does not recover them completely, after a
disruptive discharge
Note 1 to entry: In test objects, parts of both self-restoring and non-self-restoring insulation are sometimes present
in combination and some parts can be degraded by repeated or continued voltage applications. The behaviour of the
insulation in this respect should be taken into account by the relevant Technical Committee when specifying the test
procedures to be applied.
[SOURCE: IEC 60050-614:2016, 614-03-05, modified – The Note to entry has been added.]
=
IEC 60060-1:2025 © IEC 2025 – 13 –
3.6 Definitions for direct voltage tests
3.6.1
value of the test voltage
test voltage value
arithmetic mean value
3.6.2
ripple
set of unwanted periodic deviations with respect to the average value of the measured or
supplied quantity, occurring at frequencies which can be related to that of the mains supply, or
of some other definite source, such as a chopper
Note 1 to entry: Ripple is determined under specified conditions and is a part of periodic and/or random deviation
(PARD), see IEV 312-07-01.
[SOURCE: IEC 60050-312:2001, 312-07-02, modified – The Note 1 has been replaced with a
new Note 1 to entry.]
3.6.3
ripple amplitude
half the difference between the maximum and minimum values of the ripple
Note 1 to entry: In cases where the ripple shape is nearly sinusoidal, true RMS values multiplied by √2 can be used
for the determination of the ripple amplitude.
3.6.4
ripple factor
ratio of the ripple amplitude to the value of the test voltage
3.7 Terms for alternating voltage tests
3.7.1
peak value of an alternating voltage
average of the magnitudes of the positive and negative peak values
Note 1 to entry: In many cases instruments measuring only one polarity peak are used. Measuring only one polarity
is acceptable as long as waveform symmetry is within the limits set in 6.1.1.1.
3.7.2
value of the test voltage
test voltage peak value of an alternating voltage divided by 2
Note 1 to entry: The relevant Technical Committee may require a measurement of the RMS value of the test voltage
instead of the peak value for cases where the RMS value may be of importance, when the waveform is distorted.
Note 2 to entry: AC test voltage generators used in dielectric tests will of
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