36B-MT10(Washington)43 2004-12-09

INTERNATIONAL ELECTROTECHNICAL COMMISSION TECHNICAL COMMITTEE N°: 36 INSULATORS SUB-COMMITTEE 36B: INSULATORS FOR OVERHEAD LINES MAINTENANCE TEAM 10 Meeting in Washington 9th December 2004 Project 36B 61952 Ed2 Actions for 36BMT10 arising from the discussion of 36B/232/CD by SC 36B

The compiled comments received on 36B/232/CD were studied by SC 36B . The following document shows the actions to be undertaken by MT10. Actions shown in YELLOW Responsibilities in RED

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Comm National Clause/ ent N° Committee Subclause

1

Paragraph Figure/ Table

Type of comment

General

General

Japan

General

General

PL Spain

General General

General General

UK Egypt

General Introduction

MT10 Comments We agree with the Secretary 2 FR Introduction

MT10 Comments We agree with the Secretary

Date

Document

2004-09-08

36B/232/CD

Proposed change

(General / Technical / Editorial)

CZ

Last para

COMMENTS

36B(Washington/Secretariat)4

General Technical

General

The Czech NC has no comments on this draft. The Japanese National Committee of IEC TC36 has no comment on the document 36B/232/CD. The Polish NC has no comments. The Spanish National Committee has no comments on this draft We accept the proposal without comment Align with IEEE std. 987-2001. Add at end “Some designs of line post insulators may have low torsional capability. In this event, cracking of the fibre glass rod or permanent rotation of the end fittings can occur by twisting. The manufacturer should be consulted to determine the torsional capability of a given insulator.” 36B Meeting discussion & decision Not accepted There is a proposed text in 36C/150/CD Add the following paragraph to the which usefully explains the use of the introduction: 1000h test for both a.c. and d.c. "The practical use of composite insulators. We suggest reproducing it insulators covers both a.c. and d.c. here too applications. In spite of this fact a specific tracking and erosion test procedure for d.c. applications as a design test has not yet been defined and accepted. The 1 000 h a.c. tracking and erosion test of IEC 62217 is used to establish a minimum requirement for the tracking resistance of the housing material." 36B Meeting discussion & decision Accepted with Secretary’s modification

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

NC NC

NC NC NC Unnecessary. The introduction already states: “Torsion loads are not dealt with in this standard since they are usually negligible in the configuration in which line post insulators are generally used. Specific applications where high torsion loads can occur are outside the scope of this standard.”

Acceptable Suggest first sentence to read: “Composite insulators are used in both a.c. and d.c. applications.” CONV

-3Comm National Clause/ ent N° Committee Subclause

3

NL

MT10 Comments Noted 4 NL

Paragraph Figure/ Table

Type of comment

6th paragraph

Technical

Introduction

7th paragraph

Technical

MT10 Comments We agree with the Secretary

2nd para

Proposed change

(General / Technical / Editorial)

Introduction

MT10 Comments We agree with the Secretary 5 Egypt 1

COMMENTS

36B(Washington/Secretariat)4

General

In the last sentence it is stated that specific pollution tests for composite insulators are under consideration”. The Netherlands National Committee wishes to emphasise the need for pollution tests as well as artificial ageing tests for composite insulators and requests to urge this matter. 36B Meeting discussion & decision Passed on to TC 36 The 7th paragraph deals with power arc Delete this paragraph. tests. Such a test ”subject to purchaser and user” should not just be mentioned in an introduction, as the user of this document may overlook this. It has to be listed among the other tests in the standard. This is information about possible tests and should be available for the user of the standard. Therefore, include a power arc test, subject to agreement between purchaser and manufacturer, as a design test in subclause 8.1 and in clause 9.

36B Meeting discussion & decision Not accepted In spite of this document specify that “composite line post insulators covered by this standard are subjected to cantilever, tensile and compressive loads, when supporting the line conductors“ page (7), it states in page (5) that “Compression load tests are not specified in this standard”. 36B Meeting discussion & decision No action

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

This need is noted and will be passed on to TC 36

Not acceptable. Experience has shown that optional tests that are included in the list of applicable tests are very often imposed as mandatory. Power arc tests are intended to test equipment (not only the insulator, but also conductors and fittings) in conditions that reproduce the electrical and mechanical environment of a given system (Current, duration, supply and return circuit geometry etc.). It is not possible to define a generic test which could be used as a design test for all insulators, fittings and conditions.

The loads applied to line-post insulators are generally a combination of cantilever and compressive (or tensile) loads, the insulators are very rarely subjected to a pure compressive load directly along their axis. Their cantilever strength is therefore the prime characteristic to be verified.

-4Comm National Clause/ ent N° Committee Subclause

6

Egypt

Paragraph Figure/ Table

Type of comment

MT10 Comments We agree with the Secretary 8 Egypt 3

MT10 Comments We agree with the Secretary 9 CN 4

MT10 Comments We agree with the Secretary

Proposed change

(General / Technical / Editorial)

2

MT10 Comments We agree with the Secretary 7 Egypt 3

COMMENTS

36B(Washington/Secretariat)4

New clause Technical after 3.6

New clause Technical after 3.10

Paragraph 1 Technical

Add IEC 1109 (Composite insulators for a.c overhead lines with a nominal voltage greater that 1000 V. 36B Meeting discussion & decision Not accepted Add Grounding (grading?) device A device for controlling the potential gradient at the end fittings such as a metal ring or various semi conductive polymeric devices. 36B Meeting discussion & decision Not accepted Add Tracking Irreversible deterioration of surface material from the formation of conductive carbonized path . 36B Meeting discussion & decision Not accepted Only MDCL shall be marked because it In addition to the requirements of may be apparenter. (clearer ??) IEC 62217, each insulator shall be marked with the MDCL. Meanwhile the note to this clause shall be deleted.

36B Meeting discussion & decision Not accepted

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Not acceptable No reference to IEC 61109 is made in the document.

Unnecessary, this term already exists in the IEV (151-15-51)

Unnecessary, this definition is already in IEC 62217, the IEV and the TC 36 glossary (in project)

Not acceptable, the words “or with the relevant IEC designation” and the note were added deliberately to cater for a future dimensional/ designation standard for composite line post insulators. Such a designation, when created, will most certainly include the MDCL.

-5Comm National Clause/ ent N° Committee Subclause

10

Egypt

Paragraph Figure/ Table

5

MT10 Comments We agree with the Secretary 11 Italy 5

MT10 Comments We agree with the Secretary 12 Egypt 6/Annex C

MT10 Comments We agree with the Secretary 13 SE 6

Type of comment

Last line

COMMENTS

Proposed change

(General / Technical / Editorial)

Technical

Note

36B(Washington/Secretariat)4

Technical

Technical

Environmental conditions referred to IEC 62217 which specify that maximum ambient air temperature does not exceed (40 °C). However, it reaches to about (50 °C) in some desert areas where overhead lines crossing there. Also there is no significant chemical pollution specified in table (1) IEC 62217.

36B Meeting discussion & decision No action necessary About the identification exist the IEC Harmonize the clause to the IEC guide 111 that give all the information guide

36B Meeting discussion & decision Not accepted Add reference to (7) [7] IEEE std. 987 Guide for application of composite insulator.

36B Meeting discussion & decision Not accepted Editorial The text is not a part of this standard. If Paragraph deleted or as a note: found necessary the text should be in a Note note only with reference to IEC 62217 Information of handling of composite and CIGRÉ Technical Brochure 184. insulators can be found in IEC 62217 and CIGRÉ Technical Brochure 184. MT10 Comments – proposed replacement text. 36B Meeting discussion & decision MT10 proposal accepted The requirements of IEC 62217 apply. During installation, composite insulators may be submitted to torsion loads for which they are not designed. In the absence of specific guidance from the manufacturer, torsion loads leading to stress in the core above 15 MPa shall be avoided. NOTE: CIGRE Technical Brochure 184 [6] gives information on handling of composite insulators and guidance on reducing torsion loads during installation CONV plus copy to 61109

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Clause 5 of 62217 states: “The normal environmental conditions to which insulators are submitted in service are defined according to table 1. When special environmental conditions prevail at the location where insulators are to be put in service, they shall be specified by the user by reference to IEC 60721-1.” In other words, if the temperature exceeds 40° or if there is chemical pollution, the user should mention this to the supplier.

Not acceptable. Unfortunately IEC guide 111 is not totally compatible with line insulators. The relevant points from guide 111 have been adopted word for word wherever possible.

Unnecessary. The CIGRE Brochure 184 referred to in this clause is far more complete and detailed than the IEEE guide.

Partly acceptable. Suggest rewriting the clause to indicate that 62217 applies, stress from torsional loads should be limited to 15 MPa and refer to CIGRE 184 in a note.

-6Comm National Clause/ ent N° Committee Subclause

14

Italy

7

MT10 Comments We agree with the Secretary 15 FR 8.1

Paragraph Figure/ Table

1

Table 1

Type of comment

36B(Washington/Secretariat)4

COMMENTS

Proposed change

(General / Technical / Editorial)

Technical

Technical

About the Transport, storage and installation exist the IEC guide 111 that give all the informations

Harmonize the clause to the IEC guide

36B Meeting discussion & decision Not accepted The strength of the assembled core can Add crosses accordingly. be influenced by housing manufacturing parameters (e.g. temperature, pressure or chemicals). Therefore, the assembled core load tests should be extended to lines 1, 7, 8 and 12.

MT10 Comments We prefer to add the crosses as proposed by France. Additionally these crosses should have a note as follows: NOTE – Not necessary if it can be demonstrated that the change has no influence on the assembled core strength (e.g. manufacturing temperature does not change). ADDITIONALLY Line 5 should have a cross. CONV

36B Meeting discussion & decision Copy from 61109. CONV

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Not acceptable. This information, if adopted, belongs in IEC 62217. Additionally Guide 111 admits “It is impossible here to cover in detail the complete rules…” and then just gives some points for consideration with no specific details. The referenced CIGRE 184 is much more complete.

This suggestion is debatable. Line 1 (Housing materials) will not have any influence if the assembly process and parameters are the same. Line 7 (Housing manufacturing process) will have no influence in the case of slip-on” housings. Line 8 (Housing Assembly process) can have an influence for directly injected housings, but in the case of “slip-on” sheds or housings there will be no influence. Line 12 (Core/housing/end fitting interface design) may only have an influence if the geometry of the opening of the end fitting is changed. In this case it is covered by line 10 (connexion zone design) since the opening is, by definition, part of the end fitting where the loads are transferred from body to fitting. Suggest adding a line 13 for “Temperatures, pressures seen by the assembled core during manufacture”

-7Comm National Clause/ ent N° Committee Subclause

16

Germany

8.1

Paragraph Figure/ Table

Table 1

Type of comment

COMMENTS

36B(Washington/Secretariat)4 Proposed change

(General / Technical / Editorial)

Technical

The limits for housing profile without Lower limits for spacing (e.g. +/repeating the design test tracking and 10%) and shed overhang (e.g. +/erosion are very high; within this range, 7%) significant influence to the result of tracking and erosion test are obvious. It has to be considered that within the actual limits the material quality can have a significant influence. MT10 Comments 36B Meeting discussion & decision The tolerance on shed overhang is too strict. We propose +/- 10% for both spacing and MT 10 proposal accepted overhang. CONV 17 Italy 8.1 Table 1 Technical In the table item 4, any tolerance is To align at the IEC 61109 considered for the variation of the "core diameter", as specified in the IEC 61109 in the analogous table where for a variation within the 15% of the "core diameter" do not constitute a change.

MT10 Comments We agree with the Secretary (the variation is actually 62 %) 18 NL 8.1 Table 1 Technical MT10 Comments We agree with the Secretary 19 U.S. 9.2.3

MT10 Comments We agree with the Secretary

Technical

36B Meeting discussion & decision Not accepted A power arc test is missing. Add a power arc tests as design test as subclause 9.5. 36B Meeting discussion & decision Not accepted 62217 does not require removal of the “The specimens shall be as specified housing if it is not bonded to the rod. in IEC 62217.”

36B Meeting discussion & decision Align with 61109 clause 11.1.3 CONV

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Acceptable. Experience and electric field studies confirm the influence of shed geometry on localised arc activity.

Not acceptable. For suspension insulators (61109) the mechanical strength, for a given core diameter, is defined principally by the strength of the end fittings and the connection zone between fitting and core. Also the strength of the core varies with the square of the diameter. For line post insulators, the cantilever damage limit strength of the core is the prime characteristic. This varies rd with the 3 power of the diameter. A 15% variation in diameter would result in a 52% variation in strength.

Not acceptable See comment 4 above

Not acceptable The WG decided that it is preferable to remove non-bonded housings and to clean the core . The presence of sealing grease can affect the results of the tests on core materials and pollute the dye used for the dye penetration test.

-8Comm National Clause/ ent N° Committee Subclause

20

BE

9.3.1

Paragraph Figure/ Table

4th line

MT10 Comments We agree with the Secretary 21 U.S. 9.3.1

MT10 Comments We agree with the Secretary 22 U.S. 9.3.1

Type of comment

COMMENTS

Proposed change

(General / Technical / Editorial)

Editorial

Technical

Paragraph 3

36B(Washington/Secretariat)4

General

MT10 Comments We agree with the Secretary

The indication of the temperatures at which the tests must be performed is not correct. Do not use °C and K in one set of information.

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Correct the text to read: Correct. Will be modified “…one at (+50 ± 5)°C, the other at (– 35 ± 5)°C . The cold period shall be at a temperature……” CONV

36B Meeting discussion & decision Accepted The temperatures are defined with a “…Each temperature cycle has two tolerance. Then the range is defined as a temperature levels with a duration of minimum. at least 8 h, one at +50 °C ± 5K, the other at –35 °C ± 5K. The prestressing can be conducted in air or any other suitable medium.” 36B Meeting discussion & decision Not accepted The load is to be applied “The load shall be applied “perpendicularly”. Most posts have an approximately perpendicularly to the upsweep angle. Would it be more insulator’s axis at the normal appropriate to apply the loading as conductor position or hardware closely as possible to the normal attachment point.” conductor loading direction? And the loading should be applied at the normal conductor attachment point.

Not acceptable. The requirement for a minimum difference of 85 K is a supplementary requirement which limits the hot/cold tolerances.

Not acceptable This is a design test which is applicable for any service mounting position, therefore it was decided to adopt a perpendicular load for which it is easier to calculate moments. On the contrary, the type test requires the load to be applied in the direction foreseen in service.

36B Meeting discussion & decision Add “Initial direction perpendicular” MT 10 to rewrite.

The load shall be applied to the insulator at the conductor position, in a direction appropriate for the end fittings, and approximately perpendicular to the axis of the insulator at the point of application CONV 23

BE

9.4.1.1

Page 14 th 4 line

Editorial

The indication of the temperature at Correct the text to read: which the test must be performed is not “..at a temperature of (20 ± 10)°C.” correct. Do not use °C and K in one set of CONV information.

Correct. Will be modified

-9Comm National Clause/ ent N° Committee Subclause

Paragraph Figure/ Table

MT10 Comments We agree with the Secretary 24 NL 9.5

MT10 Comments We agree with the Secretary 25 Egypt 10

Line 8

Type of comment

COMMENTS

36B(Washington/Secretariat)4 Proposed change

(General / Technical / Editorial)

Technical

A power arc test is missing.

Editorial

Correct

36B Meeting discussion & decision Accepted Add: 9.5 Power arc test Subject to agreement between purchaser and manufacturer a power arc tests shall be applied as per IEC 61467. 36B Meeting discussion & decision Not accepted corrected as follows: SCL specific cantilever load

MT10 Comments 36B Meeting discussion & decision We agree with the Secretary. However there are only 5 abbreviations in the publication and No change they are already grouped together at the end of the definitions, so an abbreviations clause is probably superfluous. 26 BE 10.2.1 Editorial The indication of the temperature at Correct the text to read: “ This test shall be performed at a which the test must be performed is not correct. Do not use °C and K in one set of temperature of (20 ± 10)°C and is used…….” CONV information. MT10 Comments We agree with the Secretary 27 U.S. 11.4.1

Paragraph 2

Technical

36B Meeting discussion & decision Accepted Due to the flexibility of polymer posts and “The load shall be increased the range of lengths employed, their smoothly from zero at a rate not to deflection at SCL can range from a few exceed 40% of the SCL per minute. millimetres to a few meters. Most Precautions shall be taken to keep hydraulic systems will be unable to meet the direction of application of the the protocol at the extremes of deflection. load as parallel as possible to initial direction.”

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Not acceptable See comment 4 above

Unnecessary. The abbreviation SCL is given in the definitions. However it could be judicious to add an “Abbreviations” clause

Correct. Will be modified

Partly acceptable It is important that the SCL be reached as quickly as possible, notably within 90s. If a longer time is taken the test can be more severe. Suggest re-wording to allow a long time if the test equipment does not permit the SCL to be reached in 30s to 90s

- 10 Comm National Clause/ ent N° Committee Subclause

Paragraph Figure/ Table

Type of comment

COMMENTS

36B(Washington/Secretariat)4 Proposed change

(General / Technical / Editorial)

MT10 Comments We agree with the Secretary, reword as follows:

36B Meeting discussion & decision USA Rewording is acceptable The load shall be increased rapidly but smoothly from zero to approximately MT10 proposal accepted

75% of the SCL and then shall be gradually increased in a time between 30 s and 90 s until the SCL is reached. If the SCL is reached in less than 90 s, the load shall be maintained for the remainder of the 90 s. For test objects exhibiting large deflections it may not be possible to reach the SCL within 90 s; if this occurs then it shall be noted in the test report. CONV

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

- 11 Comm National Clause/ ent N° Committee Subclause

28

Italy

12 and 13

MT10 Comments We agree with the Secretary 29 FI B.3

MT10 Comments We agree with the Secretary

FORM 8C (IEC) 1998-03-01

Paragraph Figure/ Table

Type of comment

36B(Washington/Secretariat)4

COMMENTS

Proposed change

(General / Technical / Editorial)

Technical

Editorial

In all the document no reference is done to mechanical traction or compression both in type that in the acceptance test

OBSERVATIONS OF THE SECRETARIAT on each comment submitted

Introduce mechanical test by agreed Not acceptable between supplier and purchaser For tensile tests the design test is sufficient since the tensile resistance of the insulator does not depend on its length. Pure compression tests are of little interest since the insulators are designed to work principally under cantilever loads. 36B Meeting discussion & decision Not accepted MT = [(V2+L2)EI / T]1/2 tanh [d (T / MT = [(V2+L2)EI / T]1/2 tan [d (T / Not acceptable EI)1/2] EI)1/2] tanh is correct for tensile loads. See the following document. tanh????????? http://clumb.free.fr/36BMT10/docs/tan h.pdf 36B Meeting discussion & decision Not accepted