IEC TS 60815-2:2025
(Main)Selection and dimensioning of high-voltage insulators intended for use in polluted conditions - Part 2: Ceramic and glass insulators for a.c. systems
Selection and dimensioning of high-voltage insulators intended for use in polluted conditions - Part 2: Ceramic and glass insulators for a.c. systems
IEC TS 60815-2:2025, which is a technical specification, is applicable for the selection of ceramic and glass insulators for AC systems, and the determination of their relevant dimensions, to be used in high-voltage systems with respect to pollution. This document applies to insulators for outdoor installation only.
This document gives specific guidelines and principles to arrive at an informed judgement on the probable behaviour of a given insulator in certain pollution environments.
The basis for the structure and approach of this document is fully explained in IEC TS 60815-1.
The objective of this document is to give the user means to:
- determine the reference unified specific creepage distance (RUSCD) from site pollution severity (SPS) value or class;
- evaluate the suitability of different insulator profiles;
- determine the necessary USCD by applying corrections for insulator shape, size, position, etc. to the RUSCD;
- if required, determine the appropriate test methods and parameters to verify the performance of the selected insulators.
This second edition of IEC TS 60815-2, together with IEC TS 60815-1, cancels and replaces the first edition of IEC TS 60815-2 published in 2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) Some terms and definitions are modified or introduced in this document, such as USCD, nominal creepage distance, RUSCD, creepage factor, insulator trunk, etc.;
b) From RUSCD of reference insulator to USCD of candidate insulator, the correction factors are introduced and revised, such as altitude correction, diameter correction, shed profile correction and parallel insulator number correction;
c) Profile suitability on ceramic and glass insulators was simplified.
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Standards Content (Sample)
IEC TS 60815-2 ®
Edition 2.0 2025-12
TECHNICAL
SPECIFICATION
Selection and dimensioning of high-voltage insulators intended for use in
polluted conditions -
Part 2: Ceramic and glass insulators for AC systems
ICS 29.080.10 ISBN 978-2-8327-0761-6
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CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 6
3.2 Abbreviated terms. 6
4 Principles . 7
5 Materials. 7
6 Site pollution severity class. 8
7 Determination of the reference unified specific creepage distance (RUSCD) . 8
8 Choice of shed profile . 9
8.1 General recommendations . 9
8.2 Profile suitability . 11
9 Checking the shed profile parameters . 12
9.1 Introductory remark . 12
9.2 Alternating sheds and shed overhang . 13
9.3 Spacing versus shed overhang . 13
9.4 Minimum distance between sheds . 14
9.5 Creepage distance versus clearance . 15
9.6 Shed angle . 15
9.7 Creepage factor. 16
10 Determining USCD by correcting RUSCD . 16
10.1 Introductory remark . 16
10.2 Correction for altitude K . 17
a
10.3 Correction for insulator diameter K . 17
d
10.4 Correction for profile K . 18
s
10.5 Correction for the number of similar insulators in parallel K . 18
p
11 Determination of the final minimum creepage distance . 19
12 Confirmation by testing. 19
12.1 Introductory remark . 19
12.2 Determination of the long-duration withstand voltage . 19
12.3 Selection of the standard pollution withstand test type . 20
12.4 Artificial pollution test parameters. 20
12.5 Criteria of confirmation . 21
Bibliography . 22
Figure 1 – RUSCD as a function of SPS class . 8
Figure 2 – Typical "standard" profiles . 10
Figure 3 – Typical "open" profiles . 10
Figure 4 – Typical "anti-fog" profiles . 10
Figure 5 – Typical "alternating" profiles . 11
Figure 6 – Typical pin insulator shed profiles . 11
Figure 7 – Illustration and typical values of shed overhang . 13
Figure 8 – Spacing versus shed overhang for uniform and alternating sheds . 13
Figure 9 – Minimum distance between adjacent sheds of the same diameter for uniform
and alternating sheds. 14
Figure 10 – Creepage distance versus clearance for different sheds . 15
Figure 11 – Illustrations of shed angle . 15
Figure 12 – Correction for insulator diameter . 18
Table 1 – Principal advantages (+) and disadvantages (−) of main shed profile types . 9
Table 2 – Profile suitability, relative to a standard profile, for ceramic and glass
insulators assuming the same creepage distance per unit or string . 12
Table 3 – Classification of profile according to the values of shed overhang . 13
Table 4 – Deviations for s/p for sheds with and without under-ribs . 13
Table 5 – Deviations for c for different lengths . 14
Table 6 – Deviations for l/d for different sheds . 15
Table 7 – Deviations for shed angle . 16
Table 8 – Deviations for creepage factor . 16
Table 9 – Artificial pollution test parameters for confirmation by testing . 20
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Selection and dimensioning of high-voltage insulators intended for use in
polluted conditions -
Part 2: Ceramic and glass insulators for AC systems
FOREWORD
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IEC TS 60815-2 has been prepared by IEC technical committee 36: Insulators. It is a Technical
Specification.
This second edition of IEC TS 60815-2, together with IEC TS 60815-1, cancels and replaces
the first edition of IEC TS 60815-2 published in 2008. This edition constitutes a technical
revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Some terms and definitions are modified or introduced in this document, such as USCD,
nominal creepage distance, RUSCD, creepage factor, insulator trunk, etc.;
b) From RUSCD of reference insulator to USCD of candidate insulator, the correction factors
are introduced and revised, such as altitude correction, diameter correction, shed profile
correction and parallel insulator number correction;
c) Profile suitability on ceramic and glass insulators was simplified.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
36/615/DTS 36/635/RVDTS
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 Technical Specification is English.
This document was drafted in accordance with ISO/I
...
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