prEN IEC 62772:2022

Composite hollow core station post insulators for substations with a.c. voltage greater than 1 000 V and d.c. voltage greater than 1 500 V - Definitions, test methods and acceptance criteria

This International Standard applies to composite hollow core station post insulators consisting of a load-bearing insulating tube (core) made of resin impregnated fibres, insulating filler material (solid, liquid, gaseous - pressurized or unpressurized), a housing (outside the insulating tube) made of polymeric material (for example silicone or ethylene-propylene) and fixing devices at the ends of the insulating tube. Composite hollow core station post insulators as defined in this standard are intended for general use in substations in both, outdoor and indoor environments, operating with a rated AC voltage greater than 1 000 V a.c. and a frequency not greater than 100 Hz or for use in direct current systems with a rated voltage greater than 1 500 V.d.c. The object of this standard is: to define the terms used; to prescribe test methods; to prescribe acceptance criteria. All the tests in this standard, apart from the thermal-mechanical test, are performed at normal ambient temperature. This standard does not prescribe tests that are characteristic of the apparatus of which the composite hollow core station post insulator ultimately may form a part (e.g. disconnector switch, reactor support, HVDC valves).

Hohlkern-Verbundstützisolatoren für Schaltanlagen mit einer Wechselspannung über 1 000 V und einer Gleichspannung über 1 500 V – Begriffe, Prüfverfahren und Annahmekriterien

Isolateurs supports composites creux pour postes présentant une tension alternative supérieure à 1 000 V et une tension continue supérieure à 1 500 V - Définitions, méthodes d'essai et critères d'acceptation

Votli podporni kompozitni izolatorji za postaje z izmenično napetostjo, višjo od 1000 V, in enosmerno napetostjo, višjo od 1500 V - Definicije, preskusne metode in merila sprejemljivosti

General Information

• Status: Not Published
• Publication Date: 10-Oct-2023
• ICS: 29.080.10 - Insulators
• Technical Committee: CLC/SR 36 - Insulators for substations
• Drafting Committee: IEC/TC 36 - IEC_TC_36
• Current Stage: 4060 - Enquiry results established and sent to TC, SR, BTTF - Enquiry
• Start Date: 10-Jun-2022
• Completion Date: 10-Jun-2022
• Ref Project: oSIST prEN IEC 62772:2022 - Composite hollow core station post insulators for substations with a.c. voltage greater than 1 000 V and d.c. voltage greater than 1 500 V - Definitions, test methods and acceptance criteria

Relations

• Revises: EN 62772:2016 - Composite Hollow Core Station Post Insulators for substations with a.c. voltage greater than 1 000 V and d.c. voltage greater than 1 500 V - Definitions, test methods and acceptance criteria
• Effective Date: 12-Jan-2021

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN IEC 62772:2022
01-junij-2022
Votli podporni kompozitni izolatorji za postaje z izmenično napetostjo, višjo od

1000 V, in enosmerno napetostjo, višjo od 1500 V - Definicije, preskusne metode in

merila sprejemljivosti

Composite hollow core station post insulators for substations with a.c. voltage greater

than 1 000 V and d.c. voltage greater than 1 500 V - Definitions, test methods and

acceptance criteria

Isolateurs supports composites creux pour postes présentant une tension alternative

supérieure à 1 000 V et une tension continue supérieure à 1 500 V - Définitions,
méthodes d'essai et critères d'acceptation
Ta slovenski standard je istoveten z: prEN IEC 62772:2022
ICS:
29.080.10 Izolatorji Insulators
oSIST prEN IEC 62772:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN IEC 62772:2022
---------------------- Page: 2 ----------------------
oSIST prEN IEC 62772:2022
36/541/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62772 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-03-18 2022-06-10
SUPERSEDES DOCUMENTS:
36/510/CD, 36/532A/CC
IEC TC 36 : INSULATORS
SECRETARIAT: SECRETARY:
Sweden Mr Dan Windmar
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:

Composite hollow core station post insulators for substations with a.c. voltage greater than 1

000 V and d.c. voltage greater than 1 500 V - Definitions, test methods and acceptance criteria

PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:

Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to

download this electronic file, to make a copy and to print out the content for the sole purpose of preparing

National Committee positions. You may not copy or "mirror" the file or printed version of the document, or any

part of it, for any other purpose without permission in writing from IEC.
---------------------- Page: 3 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 2 36/541/CDV
1 CONTENTS

2 CONTENTS .......................................................................................................................... 2

3 FOREWORD ......................................................................................................................... 4

4 INTRODUCTION ................................................................................................................... 6

5 1 Scope ............................................................................................................................ 7

6 2 Normative references..................................................................................................... 7

7 3 Terms and definitions .................................................................................................... 8

8 3.30 11

9 4 Identification and marking ............................................................................................ 12

10 5 Environmental conditions ............................................................................................. 13

11 6 Information on transport, storage and installation ......................................................... 13

12 7 Classification of tests ................................................................................................... 13

13 7.1 General ............................................................................................................... 13

14 7.2 Design tests ........................................................................................................ 13

15 7.3 Type tests ........................................................................................................... 15

16 7.4 Sample tests ....................................................................................................... 16

17 7.5 Routine tests ....................................................................................................... 16

18 8 Design tests ................................................................................................................ 16

19 8.1 General ............................................................................................................... 16

20 8.2 Tests on interfaces and connections of end fittings .............................................. 17

21 8.2.1 General ....................................................................................................... 17

22 8.2.2 Test specimens ............................................................................................ 17

23 8.2.3 Reference disruptive- discharge dry power frequency voltage test ................. 17

24 8.2.4 Thermal mechanical pre-stressing test .......................................................... 17

25 8.2.5 Water immersion pre-stressing test .............................................................. 17

26 8.2.6 Verification tests .......................................................................................... 17

27 8.3 Assembled core load tests ................................................................................... 18

28 8.3.1 Test for the verification of the maximum design cantilever load (MDCL) ........ 18

29 8.3.2 Test for the verification of the maximum design torsion load (MDToL) ........... 19

30 8.3.3 Verification of the specified tension load (STL) ............................................. 19

31 8.4 Tests on shed and housing material ..................................................................... 20

32 8.4.1 Hardness test .............................................................................................. 20

33 8.4.2 Accelerated weathering test ......................................................................... 20

34 8.4.3 Tracking and erosion – 1000 h salt fog a.c. voltage test ................................ 20

35 8.4.4 Flammability test .......................................................................................... 20

36 8.4.5 Hydrophobicity transfer test .......................................................................... 20

37 8.5 Tests on the tube material ................................................................................... 20

38 8.5.1 General ....................................................................................................... 20

39 8.5.2 Porosity test (Dye penetration test) ............................................................... 20

40 8.5.3 Water diffusion test ...................................................................................... 20

41 9 Type tests ................................................................................................................... 20

42 9.1 Internal pressure test .......................................................................................... 20

43 9.2 Bending test ........................................................................................................ 21

44 9.3 Specified tension load test, compression and buckling withstand load test ............ 21

45 9.4 Electrical tests .................................................................................................... 21

46 9.4.1 Mounting arrangements for electrical tests .................................................... 21

47 9.4.2 Dry lightning impulse withstand voltage test .................................................. 21

---------------------- Page: 4 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 3 36/541/CDV

48 9.4.3 Dry or wet switching impulse withstand voltage test ...................................... 21

49 9.4.4 Dry power-frequency withstand voltage test .................................................. 21

50 9.4.5 Wet power-frequency withstand voltage test ................................................. 21

51 10 Sample tests ............................................................................................................... 22

52 11 Routine tests ............................................................................................................... 22

53 11.1 General ............................................................................................................... 22

54 11.2 Routine seal leak rate test ................................................................................... 22

55 11.2.1 Test procedure ............................................................................................. 22

56 11.2.2 Acceptance criteria ...................................................................................... 22

57 12 Documentation ............................................................................................................ 23

58 Annex A (informative) Qualification of fillers ....................................................................... 24

59 A.1 Introduction ......................................................................................................... 24

60 A.2 Dye penetration test with solid filler ..................................................................... 24

61 A.3 Water diffusion test with solid filler ...................................................................... 24

62 A.4 Tests on interfaces and connections of end fittings with filler ................................ 24

63 Annex B (informative) Load definitions, relationship of loads ............................................... 26

64 Annex C (informative) Principle sketch of hollow insulators design assembly ....................... 29

66 Figure A.1 – Example of sample preparation for water diffusion test ..................................... 25

68 Table 1 – Required design and type tests ............................................................................ 14

---------------------- Page: 5 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 4 36/541/CDV
71 INTERNATIONAL ELECTROTECHNICAL COMMISSION
72 ____________
74 COMPOSITE HOLLOW CORE STATION POST INSULATORS
75 WITH A.C. VOLTAGE GREATER THAN
76 1 000 V AND D.C. VOLTAGE GREATER THAN 1 500 V –
77 DEFINITIONS, TEST METHODS AND ACCEPTANCE CRITERIA
79 FOREWORD

80 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

81 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

82 international co-operation on all questions concerning standardization in the electrical and electronic fields. To

83 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

84 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

85 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

86 in the subject dealt with may participate in this preparatory work. International, governmental and non-

87 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

88 with the International Organization for Standardization (ISO) in accordance with conditions determined by

89 agreement between the two organizations.

90 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

91 consensus of opinion on the relevant subjects since each technical committee has representation from all

92 interested IEC National Committees.

93 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

94 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

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

96 misinterpretation by any end user.

97 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

98 transparently to the maximum extent possible in their national and regional publications. Any divergence

99 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

100 the latter.

101 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

102 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

103 services carried out by independent certification bodies.

104 6) All users should ensure that they have the latest edition of this publication.

105 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

106 members of its technical committees and IEC National Committees for any personal injury, property damage or

107 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

108 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

109 Publications.

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

111 indispensable for the correct application of this publication.

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

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

114 International Standard IEC 62772 has been prepared by IEC technical committee 36:

115 Insulators.
116 The text of this standard is based on the following documents:
FDIS Report on voting
To be completed/FDIS To be completed/RVD
117

118 Full information on the voting for the approval of this standard can be found in the report on

119 voting indicated in the above table.

120 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 6 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 5 36/541/CDV

121 The committee has decided that the contents of this publication will remain unchanged until

122 the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data

123 related to the specific publication. At this date, the publication will be
124 • reconfirmed,
125 • withdrawn,
126 • replaced by a revised edition, or amended.
127
---------------------- Page: 7 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 6 36/541/CDV
128 INTRODUCTION

129 Composite hollow core station post insulators consist of an insulating hollow core (tube),

130 bearing the mechanical load protected by a polymeric housing, the load being transmitted to

131 the core by end fittings. The hollow core is filled entirely with an insulating material. The core

132 is made of resin impregnated fibres.

133 Composite hollow core station post insulators are typically applied as post insulators in

134 substations. In order to perform the design tests, IEC 62217 is to be applied for materials and

135 interfaces of the insulator. Some tests have been grouped together as "design tests", to be

136 performed only once on insulators which satisfy the same design conditions. For all design

137 tests on composite hollow core station post insulators, the common clauses defined in

138 IEC 62217 are applied. As far as practical, the influence of time on the electrical and

139 mechanical properties of the components (core material, housing, interfaces etc.) and of the

140 complete composite hollow core station post insulator has been considered in specifying the

141 design tests to ensure a satisfactory life-time under normally known stress conditions in

142 service.

143 This standard relates to IEC 61462, Composite hollow insulators – Pressurized and

144 unpressurized insulators for use in electrical equipment with rated voltage greater than

145 1 000 V – Definitions, test methods, acceptance criteria and design recommendations, as well

146 as IEC 62231, Composite station post insulators for substations with a.c. voltages greater

147 than 1 000 V up to 245 kV – Definitions, test methods and acceptance criteria. Tests and

148 requirements described in IEC 62231 can be used despite the intended operating voltage limit

149 for substations.

150 The use of polymeric housing materials that show hydrophobicity and hydrophobicity transfer

151 mechanism (HTM) is preferred for composite hollow core station post insulators. This is due

152 to the fact that the influence of diameter can be significant for hydrophilic surfaces (see also

153 IEC 60815-3). For instance silicone rubber is recognized as successful countermeasure

154 against severe polluted service conditions. For the time being, the 1 000 h a.c. tracking and

155 erosion test of IEC 62217 is used to establish a minimum requirement for the tracking and

156 erosion resistance, for both a.c. and d.c.. In IEC 62217 tests are defined to quantify the HTM

157 performance.

158 Composite hollow core station post insulators are used in both a.c. and d.c. applications.

159 Before the appropriate standard for d.c. applications will be issued, the majority of tests listed

160 in this standard can also be applied to d.c. insulators. In spite of this, a specific tracking and

161 erosion test procedure for d.c. applications as a design test is still being considered to be

162 developed. Some information about the difference of a.c. and d.c. material erosion test can be

163 found in the CIGRE Technical Brochure 611 [REF]. For the time being, the 1 000 h a.c.

164 tracking and erosion test of IEC 62217 is used to establish a minimum requirement for the

165 tracking and erosion resistance.
166
167
---------------------- Page: 8 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 7 36/541/CDV
168 COMPOSITE HOLLOW CORE STATION POST INSULATORS
169 WITH A.C. VOLTAGE GREATER THAN
170 1 000 V AND D.C. VOLTAGE GREATER THAN 1 500 V –
171 DEFINITIONS, TEST METHODS AND ACCEPTANCE CRITERIA
172
173
174
175 1 Scope

176 This International Standard applies to composite hollow core station post insulators consisting

177 of a load-bearing insulating tube (core) made of resin impregnated fibres, insulating filler

178 material (solid, liquid, gaseous – pressurized or unpressurized), a housing (outside the

179 insulating tube) made of polymeric material (for example silicone or ethylene-propylene) and

180 fixing devices at the ends of the insulating tube. Composite hollow core station post insulators

181 as defined in this standard are intended for general use in substations in both, outdoor and

182 indoor environments, operating with a rated AC voltage greater than 1 000 V a.c. and a

183 frequency not greater than 100 Hz or for use in direct current systems with a rated voltage

184 greater than 1 500 V.d.c.
185 The object of this standard is:
186 to define the terms used;
187 to prescribe test methods;
188 to prescribe acceptance criteria.

189 All the tests in this standard, apart from the thermal-mechanical test, are performed at normal

190 ambient temperature. This standard does not prescribe tests that are characteristic of the

191 apparatus of which the composite hollow core station post insulator ultimately may form a part

192 (e.g. disconnector switch, reactor support, HVDC valves).
193 2 Normative references

194 The following documents are referred to in the text in such a way that some or all of their

195 content constitutes requirements of this document. For dated references, only the edition

196 cited applies. For undated references, the latest edition of the referenced document (including

197 any amendments) applies.

198 IEC 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements

199 IEC 60168, Tests on indoor and outdoor post insulators of ceramic material or glass for

200 systems with nominal voltages greater than 1 000 V

201 IEC 61109, Insulators for overhead lines – Composite suspension and tension insulators for

202 a.c. systems with a nominal voltage greater than 1 000 V – Definitions, test methods and

203 acceptance criteria

204 IEC 61462, Composite hollow insulators – Pressurized and unpressurized insulators for use in

205 electrical equipment with rated voltage greater than 1 000 V – Definitions, test methods,

206 acceptance criteria and design recommendations

207 IEC 62217, Polymeric HV insulators for indoor and outdoor use – General definitions, test

208 methods and acceptance criteria

209 IEC 62231, Composite station post insulators for substations with a.c. voltages greater than1

210 000 V up to 245 kV – Definitions, test methods and acceptance criteria
---------------------- Page: 9 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 8 36/541/CDV
211
212 3 Terms and definitions

213 For the purposes of this document, the following terms and definitions apply.

214 3.1
215 composite hollow core station post insulator

216 post insulator, consisting of at least three insulating parts, namely a tube, a housing with or

217 without sheds, and an internal filler. End fittings are attached to the insulating tube. The

218 housing with or without sheds, may be omitted in case of specific environmental conditions

219 (e.g. indoor).and applications .

220 Note 1 to entry: A hollow insulator can be made from one or more permanently assembled insulating elements

221 [IEV 471-01-08, modified]
222 3.2
223 post insulator

224 insulator intended to give rigid support to a live part which is to be insulated from earth or

225 from another live part

226 Note 1 to entry: A post insulator may be an assembly of a number of post insulator units (stack).

227 Note 2 to entry: Post insulators for substations are also known as station post insulators.

228 [IEV 471-04-01, modified]
229 3.3
230 tube (core)

231 central internal insulating part of a composite hollow core station post insulator which

232 provides the mechanical characteristics

233 Note 1 to entry: The housing, insulating filler material and sheds are not part of the core.

234 Note 2 to entry: Resin impregnated fibres are structured in such a manner as to achieve sufficient mechanical

235 strength. Layers of different fibres may be used to fulfil special requirements.

236 3.4
237 filler

238 insulating material filling the entire internal space (solid, liquid, gaseous – pressurized or

239 unpressurized) of the hollow core station post insulator
240 3.5
241 fixing device (end fitting)

242 integral component or formed part of an insulator intended to connect it to a supporting

243 structure, or to a conductor, or to an item of equipment, or to another insulator

244 Note 1 to entry: Where the end fitting is metallic, the term “metal fitting” is normally used.

245 [SOURCE: IEC 60050-471:2007, 471-01-06, modified by the addition of a synonym]

246 3.6
247 coupling

248 part of the end fitting which transmits the load to the accessories external to the insulator

249 [SOURCE: IEC 62217, section 3]
---------------------- Page: 10 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 9 36/541/CDV
250 3.7
251 connection zone

252 zone where the mechanical load is transmitted between the insulating body and the end fitting

253 [SOURCE: IEC 62217, section 3]
254 3.8
255 housing

256 external insulating part of composite hollow core station post insulator providing necessary

257 creepage distance and protecting the tube from the environment

258 Note 1 to entry: If an intermediate sheath is used it forms a part of the housing

259 [SOURCE: IEC 62217, section 3]
260 3.9
261 shed

262 insulating part, projecting from the insulator trunk, intended to increase the creepage distance

263 Note 1 to entry: The shed can be with or without ribs
264 [SOURCE: IEC 60050-471:2007, 471-01-15]
265 3.10
266 insulator trunk
267 central insulating part of an insulator from which the sheds project
268 Note 1 to entry: Also known as shank on smaller insulators.
269 [SOURCE: IEC 60050-471:2007, 471-01-11]
270 3.11
271 creepage distance

272 shortest distance or the sum of the shortest distances along the surface of an insulator

273 between two conductive parts which normally have the operating voltage between them

274 Note 1 to entry: The surface of any non-insulating jointing material is not considered as forming part of the

275 creepage distance.
276 [SOURCE: IEC 60050-471:2007, 471-01-04, modified]
277 3.12
278 arcing distance

279 shortest distance in the air external to the insulator between the metallic parts which normally

280 have the operating voltage between them
281 [SOURCE: IEC 60050-471:2007, 471-01-01]
282 3.13
283 interface
284 contact surface between the different materials

285 Note 1 to entry: Various interfaces occur in most composite insulators (cf. Annex C), e.g.

286 between housing and end fittings,

287 between various parts of the housing; e.g. between sheds, or between sheath and sheds,

288 between tube and housing
289 between tube and filler.
290 [SOURCE: IEC 62217, section 3]
---------------------- Page: 11 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 10 36/541/CDV
291 3.14
292 damage limit of the tube under mechanical stress

293 limit below which mechanical loads can be applied, at normal ambient temperature, without

294 micro damage to the composite tube

295 Note 1 to entry: Applying such loads means that the tube is in a reversible elastic phase. If the damage limit of

296 the tube is exceeded, the tube is in an irreversible plastic phase, which means permanent damage to the tube

297 which may not be visible at a macroscopic level (for a quantitative definition see Annex C of IEC 61462 ED2).

298 3.15
299 maximum mechanical load
300 MML

301 highest cantilever bending load which is expected to be applied to the composite hollow core

302 station post insulators in accordance with IEC 61462

303 Note 1 to entry: The MML of the composite hollow core station post insulator is specified by the insulator

304 manufacturer.
305 3.16
306 specified mechanical load
307 SML

308 cantilever bending load specified by the manufacturer that is used in the mechanical tests,

309 and which is verified during a type test at normal ambient temperature

310 Note 1 to entry: The SML forms the basis of the selection of composite hollow station post insulators with regard

311 to external loads.
312 3.17
313 specified cantilever load
314 SCL

315 cantilever load to be withstood by the insulator when tested under the prescribed conditions in

316 accordance with IEC 62231
317 3.18
318 maximum design cantilever load
319 MDCL

320 load level above which damage to the insulator begins to occur and that should not be

321 exceeded in service in accordance with IEC 62231.

322 Note to entry: For more information to load philosopies and relationships, see Annex B

323 3.19
324 specified torsion load
325 SToL

326 torsion load level which can be withstood by the insulator when tested under the prescribed

327 conditions in accordance with IEC 62231
328 3.20
329 maximum design torsion load
330 MDToL

331 load level above which damage to the insulator begins to occur and that should not be

332 exceeded in service in accordance with IEC 62231
333 3.21
334 specified tension load
335 STL

336 tension load which can be withstood by the insulator when tested under the prescribed

337 conditions in accordance with IEC 62231
---------------------- Page: 12 ----------------------
oSIST prEN IEC 62772:2022
IEC CDV 62772 © IEC 2022 11 36/541/CDV
338 3.22
339 maximum design tension load
340 MDTL

341 load level above which damage to the insulator begins to occur and that should not be

342 exceeded in service in accordance with IEC 62231
343 3.23
344 specified compression load
345 SCoL

346 compression load to be withstood by the insulator when tested under the prescribed

347 conditions in accordance with IEC 62231
348 3.24
349 buckling load

350 compression load that induces buckling of the insulator core in accordance with IEC 62231

351 3.25
352 maximum design compression load
353 MDCoL

354 load level above which damage to the insulator begins to occur and that should not be

355 exceeded in service in accordance with IEC 62231
356 3.26
357 failing load of a composite hollow core station post insulator

358 load at ultimate failure of the insulator, maximum load that can be reached when the insulator

359 is tested under the p
...