Dielectric and resistive properties of solid insulating materials - Part 2-2: Relative permittivity and dissipation factor - High frequencies (1 MHz to 300 MHz) - AC methods

IEC 62631-2-2:2022 specifies test methods for the determination of permittivity and dissipation factor properties of solid insulating materials in a high frequency range from 1 MHz to 300 MHz.

Propriétés diélectriques et résistives des matériaux isolants solides - Partie 2-2: Permittivité relative et facteur de dissipation - Hautes fréquences (1 MHz à 300 MHz) - Méthodes en courant alternatif

L'IEC 62631-2-2:2022 spécifie les méthodes d'essai pour déterminer les propriétés de la permittivité et du facteur de dissipation de matériaux isolants solides dans la plage des hautes fréquences de 1 MHz à 300 MHz.

General Information

Status
Published
Publication Date
06-Apr-2022
Current Stage
PPUB - Publication issued
Completion Date
07-Apr-2022
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IEC 62631-2-2:2022 - Dielectric and resistive properties of solid insulating materials - Part 2-2: Relative permittivity and dissipation factor - High frequencies (1 MHz to 300 MHz) - AC methods
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IEC 62631-2-2
Edition 1.0 2022-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Dielectric and resistive properties of solid insulating materials –
Part 2-2: Relative permittivity and dissipation factor – High frequencies
(1 MHz to 300 MHz) – AC methods
Propriétés diélectriques et résistives des matériaux isolants solides –
Partie 2-2: Permittivité relative et facteur de dissipation – Hautes fréquences
(1 MHz à 300 MHz) – Méthodes en courant alternatif
IEC 62631-2-2:2022-04(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 62631-2-2
Edition 1.0 2022-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Dielectric and resistive properties of solid insulating materials –
Part 2-2: Relative permittivity and dissipation factor – High frequencies
(1 MHz to 300 MHz) – AC methods
Propriétés diélectriques et résistives des matériaux isolants solides –
Partie 2-2: Permittivité relative et facteur de dissipation – Hautes fréquences
(1 MHz à 300 MHz) – Méthodes en courant alternatif
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.99; 29.035.01 ISBN 978-2-8322-1096-7

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

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

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 62631-2-2:2022 © IEC 2022
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Methods of test ................................................................................................................ 8

4.1 Basic theory ............................................................................................................ 8

4.2 Distinctive factors for the measurement in high frequency range ........................... 12

4.3 Power supply ........................................................................................................ 13

4.4 Equipment ............................................................................................................ 13

4.4.1 Accuracy ....................................................................................................... 13

4.4.2 Distinctive feature of equipment for measurement in high frequency

range ............................................................................................................. 14

4.4.3 Choice of measurement methods ................................................................... 15

4.5 Calibration ............................................................................................................ 16

4.6 Test specimen ...................................................................................................... 16

4.6.1 General ......................................................................................................... 16

4.6.2 Recommended dimensions of test specimen and electrode

arrangements ................................................................................................ 16

4.6.3 Number of test specimens ............................................................................. 16

4.6.4 Conditioning and pre-treatment of test specimen ........................................... 16

4.7 Procedures for specific materials .......................................................................... 17

5 Test procedure .............................................................................................................. 17

5.1 General ................................................................................................................. 17

5.2 Calculation of permittivity and relative permittivity ................................................. 17

5.2.1 Relative permittivity ....................................................................................... 17

5.2.2 Dielectric dissipation factor tan δ ................................................................... 17

6 Report ........................................................................................................................... 17

7 Repeatability and reproducibility .................................................................................... 18

Annex A (informative) Compensation method using a series circuit ...................................... 19

Annex B (informative) Parallel electrodes with shield ring .................................................... 20

Annex C (informative) Apparatus ......................................................................................... 21

C.1 Parallel T network bridge ...................................................................................... 21

C.2 Resonance method ............................................................................................... 22

C.3 I-V method designed for high frequencies ............................................................. 24

C.4 Auto-balancing bridge method ............................................................................... 24

Annex D (informative) Non-contacting electrode method with micrometer-controlled

parallel electrodes in air ........................................................................................................ 26

Bibliography .......................................................................................................................... 28

Figure 1 – Dielectric dissipation factor .................................................................................. 10

Figure 2 – Equivalent circuit diagrams with capacitive test specimen .................................... 11

Figure 3 – Equivalent parallel circuit for test fixture with sample and leads to

equipment ............................................................................................................................. 12

Figure 4 – Existence of residual impedance and stray capacitance in directly

connected system ................................................................................................................. 15

---------------------- Page: 4 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 3 –

Figure A.1 – Compensation method using a series circuit ..................................................... 19

Figure B.1 – Configuration of parallel electrode with shield ring ............................................ 20

Figure C.1 – Parallel T network, principal circuit diagram ...................................................... 21

Figure C.2 – Parallel T network, practical circuit diagram ...................................................... 21

Figure C.3 – Principle of resonance method, circuit diagram (originally from Q meter) .......... 23

Figure C.4 – Auto-balancing circuit ....................................................................................... 25

Figure D.1 – Non-contacting electrode method ..................................................................... 27

Table 1 – Applicable frequency range in effective apparatus ................................................. 16

---------------------- Page: 5 ----------------------
– 4 – IEC 62631-2-2:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIELECTRIC AND RESISTIVE PROPERTIES OF
SOLID INSULATING MATERIALS –
Part 2-2: Relative permittivity and dissipation factor –
High frequencies (1 MHz to 300 MHz) – AC methods
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

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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

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Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 62631-2-2 has been prepared by of IEC technical committee 112: Evaluation and

qualification of electrical insulating materials and systems. It is an International Standard.

The text of this International Standard is based on the following documents:
Draft Report on voting
112/562/FDIS 112/565/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.
---------------------- Page: 6 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 5 –

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/standardsdev/publications.

A list of all parts in the IEC 62631 series, published under the general title Dielectric and

resistive properties of solid insulating materials, 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,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC 62631-2-2:2022 © IEC 2022
INTRODUCTION

Permittivity and dissipation factor (tan δ) are basic parameters for the quality of insulating

materials. The dissipation factor depends on several parameters, such as environmental factors,

moisture, temperature, applied voltage, and highly depends on frequency, the accuracy of

measuring apparatus and other parameters applied to the measured specimen.

The frequency range measurable for permittivity and dissipation factor is highly limited by the

design of the electrode system, dimension of the sample and impedance of the wiring lead.

Special consideration should be given to the measurement in the high frequency range. This

document focuses on the method for measurements of permittivity and dissipation factor in the

high frequency range from 1 MHz to 300 MHz.
---------------------- Page: 8 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 7 –
DIELECTRIC AND RESISTIVE PROPERTIES OF
SOLID INSULATING MATERIALS –
Part 2-2: Relative permittivity and dissipation factor –
High frequencies (1 MHz to 300 MHz) – AC methods
1 Scope

This part of IEC 62631 specifies test methods for the determination of permittivity and

dissipation factor properties of solid insulating materials in a high frequency range from 1 MHz

to 300 MHz.
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 60212, Standard conditions for use prior to and during the testing of solid electrical

insulating materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1
solid electrical insulating material

solid with negligibly low electric conductivity, used to separate conducting parts at different

electrical potentials

Note 1 to entry: The term "electrical insulating material" is sometimes used in a broader sense to designate also

insulating liquids and gases. Insulating liquids are covered by IEC 60247 [1].
3.2
dielectric properties

comprehensive behaviour of an insulating material measured with an alternating current

comprising the capacitance, absolute permittivity, relative permittivity, relative complex

permittivity, dielectric dissipation factor
3.3
absolute permittivity
electric flux density divided by the electric field strength
---------------------- Page: 9 ----------------------
– 8 – IEC 62631-2-2:2022 © IEC 2022
3.4
vacuum permittivity

permittivity of a vacuum, which is related to the magnetic constant ε μ and to the speed of light

0 0
in vacuum c by the relation ε μ c = 1
0 0 0 0
3.5
relative permittivity
ratio of the absolute permittivity to the permittivity of a vacuum ε
3.6
relative complex permittivity

permittivity in a complex number representation, under steady sinusoidal field conditions

3.7
dielectric dissipation factor tan δ (loss tangent)

numerical value of the ratio of the imaginary to the real part of the complex permittivity

3.8
capacitance

property of an arrangement of conductors and dielectrics which permits the storage of electrical

charge when a potential difference exists between the conductors
3.9
voltage application
application of a voltage between electrodes

Note 1 to entry: Voltage application is sometimes referred to as electrification.

3.10
measuring electrodes

conductors applied to, or embedded in, a material to make contact with it to measure its

dielectric or resistive properties

Note 1 to entry: The design of the measuring electrodes depends on the specimen and the purpose of the test.

4 Methods of test
4.1 Basic theory

Capacitance C is the property of an arrangement of conductors and dielectrics which permits

the storage of electrical charge when a potential difference exists between the conductors.

C is the ratio of a quantity q of charge to a potential difference U. A capacitance value is always

positive. The unit is farad when the charge is expressed in coulomb and the potential in volts.

C= (1)
---------------------- Page: 10 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 9 –

The measured permittivity (formerly known as dielectric constant) ε of an insulating material is

the product of its relative permittivity ε and the permittivity of a vacuum ε :
r 0
ε = ε · ε
(2)
0 r

This general method describes common values for general measurements. If a method for a

specific type of material is described in this document, the specific method shall be used.

The permittivity is expressed in farad per metre (F/m); the permittivity of vacuum ε has the

following value:
−12
(3)
ε 8,854187817×10

Relative permittivity is the ratio of the absolute permittivity to the permittivity of a vacuum ε .

In the case of constant fields and alternating fields of sufficiently low frequency, the relative

permittivity of an isotropic or quasi-isotropic dielectric is equal to the ratio of the capacitance of

a capacitor, in which the space between and around the electrodes is entirely and exclusively

filled with the dielectric, to the capacitance of the same configuration of electrodes in vacuum.

ε =
(4)

The relative permittivity ε of dry air, at normal atmospheric pressure, equals 1,000 59, so that

in practice, the capacitances C of the configuration of electrodes in air can normally be used

instead of C to determine the relative permittivity ε with sufficient accuracy.
0 r

Relative complex permittivity is permittivity in a complex number representation under steady

sinusoidal field conditions expressed as
'" − jδ
ε=ε−jε=ε e (5)
rr r r
' "
where ε and ε have positive values.
r r
' "

NOTE 1 The complex permittivity ε is customarily quoted either in terms of ε and ε , or in terms of ε and tan δ.

r r r
NOTE 2 ε is termed loss index.

The dielectric dissipation factor tan δ (loss tangent) is the numerical value of the ratio of the

imaginary to the real part of the complex permittivity.
---------------------- Page: 11 ----------------------
– 10 – IEC 62631-2-2:2022 © IEC 2022
Key
U applied voltage
I current
I real part of current
I imaginary part of current
φ phase difference between applied voltage and current
δ subtracted angle of φ from
Figure 1 – Dielectric dissipation factor
tanδ= (6)

Thus, the dielectric dissipation factor tan δ of an insulating material is the tangent of the angle

δ by which the phase difference φ between the applied voltage and the resulting current deviates

from π/2 rad when the solid insulating material is exclusively used as dielectric in a capacitive

test specimen (capacitor), compared with Figure 1. The dielectric dissipation factor can also be

expressed by an equivalent circuit diagram using an ideal capacitor with a resistor in series or

parallel connection (see Figure 2).
tanδ ωC ×R
ss (7)
ωC ×R
with
(8)
1+ tan δ
---------------------- Page: 12 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 11 –
and
(9)
tan δ

NOTE 3 R and R respectively are not directly related to but affected by the volume and the surface resistance of

s p

an insulating material. Therefore, the dielectric dissipation factor can also be affected by these resistive materials

properties.
Key
C and R capacitance and resistance for equivalent parallel circuit, respectively
p p
C and R capacitance and resistance for equivalent series circuit, respectively
s s
Figure 2 – Equivalent circuit diagrams with capacitive test specimen

This general method describes common values for general measurements. If a method for a

specific type of material is described in this document, the specific method shall be used.

---------------------- Page: 13 ----------------------
– 12 – IEC 62631-2-2:2022 © IEC 2022
Key
a and b terminals

C R and Z capacitance, resistance and impedance for equivalent parallel circuit with sample P,

p p P
respectively

R , L , C and Z Z is the impedance due to the residual resistance R and residual inductance L

lead lead
lead lead lead lead lead

existing with leads from the equipment to the test fixture. The stray capacitor, C is

lead
the stray capacitor involved in Z
lead

C , R and Z Z is the impedance due to the edge capacitance of the electrode and leakage

edge leak edge edge
resistance on sample and insulators of the electrode fixture

Figure 3 – Equivalent parallel circuit for test fixture with sample and leads to equipment

The measurement of permittivity and dielectric dissipation factor shall be made taking into

consideration the electric properties of the measuring circuit as well as the specific electric

properties of the material. To carry out the test, in most cases, the use of high voltage is

necessary. Care should be taken to prevent any electric shock.

The basic principles of apparatus and methods are not described here. Some references to the

literature are given in the bibliography of IEC 62631-2-1 [2] .
4.2 Distinctive factors for the measurement in high frequency range

Figure 3 shows an equivalent parallel circuit comprising an electrode system with a sample and

wiring leads from terminals a and b.

The impedance of C , , decreases when the frequency is increased, which causes the

jωC

increase in current through C in the high frequency range. When the frequency is increased

from 100 kHz to 100 MHz, the current through C increases 1 000 times more than that at

100 kHz. This causes a decrease of accuracy in the obtained results.
___________
Numbers in square brackets refer to the bibliography.
---------------------- Page: 14 ----------------------
IEC 62631-2-2:2022 © IEC 2022 – 13 –

The impedances due to the inductance of leads (L ), and the stray capacitance (C ) also

lead lead

depend on the frequency. That kind of impedance can be ignored in the measurements in the

low frequency range. In the high frequency range, on the other hand, the effect of the impedance

of Z on the measured values cannot be ignored and causes errors in the measured results.

edge

The impedance due to Z is also a significant factor in the high frequency range. R which

edge leak

is independent of the frequency could be negligible, because the leakage current on the sample

surface is much smaller than the current through the edge capacitance in the high frequency

range.

In the low frequency range, as described in IEC 62631-2-1, effective guarding and shielding

should be applied to avoid measurement errors resulting from the stray capacitance and the

residual impedance. In the frequency range higher than 100 kHz, however, the current through

the guard and shielding are significant in comparison with the current through the specimen in

the lower frequency range. Furthermore, care should be taken to prevent any electromagnetic

interference (EMI) during measurements in the radio frequency range.

NOTE 1 Since the impedance of a capacitor is inversely proportional to frequency, at high frequencies it is

essentially acting as a wire.

NOTE 2 The stray capacitance is the additional capacitance which exists in parallel with the capacitance of the test

specimen. The stray capacitance also exists between the ground and a lead line connecting a terminal of an

equipment to an electrode.

NOTE 3 The residual impedance is the impedance existing in series with the impedance of the test specimen. The

residual impedance includes an impedance of the electrode produced on the surface of the

...

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