BS PD IEC TS 62073-2016 Guidance on the measurement of hydrophobicity of insulator surfaces《绝缘子表面疏水性的测量指南》.pdf

1、BSI Standards Publication Guidance on the measurement of hydrophobicity of insulator surfaces PD IEC/TS 62073:2016National foreword This Published Document is the UK implementation of IEC/TS 62073:2016. The UK participation in its preparation was entrusted to Technical Committee PEL/36, Insulators f

2、or power systems. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016. Pub

3、lished by BSI Standards Limited 2016 ISBN 978 0 580 83669 5 ICS 29.080.10 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 March 2016. Amendments/corrigenda

4、 issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TS 62073:2016 IEC TS 62073 Edition 2.0 2016-02 TECHNICAL SPECIFICATION Guidance on the measurement of hydrophobicity of insulator surfaces INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 29.080.10 ISBN 978-2-8322-3169-2 Registered

5、trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. PD IEC/TS 62073:2016 2 IEC TS 62073:2016 IEC 2016 CONTENTS FOREWORD . 4 INTRODUCTION . 6 1 Scope 7 2 Terms and definitions 7 3 Methods for measurement of h

6、ydrophobic properties 9 3.1 General . 9 3.2 Method A Contact angle method . 9 3.2.1 General . 9 3.2.2 Equipment . 9 3.2.3 Measurement procedure . 9 3.2.4 Static contact angle measurements 10 3.2.5 Dynamic contact angle measurements 10 3.2.6 Evaluation 10 3.3 Method B Surface tension method 11 3.3.1

7、General . 11 3.3.2 Safety precautions . 11 3.3.3 Equipment and reagents 11 3.3.4 Measurement procedure . 12 3.3.5 Evaluation 12 3.4 Method C The spray method . 12 3.4.1 General . 12 3.4.2 Equipment . 12 3.4.3 Measurement procedure . 13 3.4.4 Evaluation 13 3.5 Documentation 14 Annex A (normative) Gui

8、delines regarding the applicability and comments on the limitations of the different methods described in this technical specification 15 A.1 General . 15 A.2 Typical results obtained with the three methods . 15 Annex B (normative) Method A Contact angle method 17 Annex C (normative) Method B Surfac

9、e tension method . 18 Annex D (normative) Method C Spray method . 20 Figure 1 Definition of the static contact angle . 8 Figure 2 Definition of the advancing angle ( a ) and the receding angle ( r ) inside a liquid drop resting on an inclined solid surface . 8 Figure 3 Measurements of the advancing

10、angle ( a ) and the receding angle ( r ) by adding or withdrawing water from a droplet 10 Figure B.1 Measurement of the advancing angle ( a ) and the receding angle ( r ) by using the captive bubble technique 17 Figure D.1 Examples of surfaces with hydrophobicity class (HC) from 1 to 6 . 20 Table 1

11、Criteria for the determination of hydrophobicity class (HC) 14 PD IEC/TS 62073:2016IEC TS 62073:2016 IEC 2016 3 Table C.1 Concentrations of ethylene-glycol-monoethyl-ether (cellosolve), formamide mixtures used in measuring surface tension of insulator surfaces in the range 30 mN/m to 56 mN/m (T = 20

12、 C) . 18 Table C.2 Concentrations of distilled water and formamide mixture used in measuring surface tension of insulator surfaces in the range 58 mN/m to 73 mN/m (T = 20 C) 19 Table C.3 Concentrations of distilled water and sodium chloride in mixtures used in measuring surface tension of insulator

13、surfaces in the range 73 mN/m to 82 mN/m (T = 20 C) 19 PD IEC/TS 62073:2016 4 IEC TS 62073:2016 IEC 2016 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ GUIDANCE ON THE MEASUREMENT OF HYDROPHOBICITY OF INSULATOR SURFACES FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide orga

14、nization 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,

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17、y 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

18、) 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 ar

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20、he 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 responsi

21、ble 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 commit

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23、s. 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

24、 rights. IEC shall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. In exceptional circumstances, a technical committee may propose the publication of a technical specification when the required su

25、pport cannot be obtained for the publication of an International Standard, despite repeated efforts, or the subject is still under technical development or where, for any other reason, there is the future but no immediate possibility of an agreement on an International Standard. Technical specificat

26、ions are subject to review within three years of publication to decide whether they can be transformed into International Standards. IEC 62073, which is a technical specification, has been prepared by IEC technical committee 36: Insulators. This second edition cancels and replaces the first edition

27、published in 2003. This edition constitutes a technical revision. PD IEC/TS 62073:2016IEC TS 62073:2016 IEC 2016 5 This edition includes the following significant technical changes with respect to the previous edition: a) Changed wettability to hydrophobicity throughout the document b) Redefined the

28、 criteria for the determination of hydrophobicity class in paragraph 3.4; The text of this technical specification is based on the following documents: Enquiry draft Report on voting 36/363/DTS 36/367/RVC Full information on the voting for the approval of this technical specification can be found in

29、 the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC website under “http:/webstore.i

30、ec.ch“ in the data related to the specific publication. At this date, the publication will be transformed into an International standard, reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. PD IEC/TS 62073:2016 6 I

31、EC TS 62073:2016 IEC 2016 INTRODUCTION The wetting properties of a surface by water are commonly described by the terms hydrophobic (or hydrophobicity) and hydrophilic (or hydrophilicity). A hydrophobic surface is water-repellent, while a surface that is easily wetted by water is hydrophilic. The we

32、tting phenomenon of a surface is complex and many different parameters can influence its hydrophobic properties. Some important parameters include: type of insulator material, surface roughness, heterogeneities of the surface, chemical composition (e.g. due to ageing) and presence of pollution. For

33、insulator materials in common use, the hydrophobic properties can change over time, due to the influence of the ambient conditions. This change can be either reversible or irreversible. Thus, the result of the measurement of the hydrophobicity may be influenced by the ambient conditions and the HV c

34、orona or dry-band arcing to which the insulator has been previously exposed. This dynamic behaviour of the hydrophobicity is more or less specific to different insulator materials. These types of materials, which have an ability to retain and transfer hydrophobicity, are commonly called Hydrophobici

35、ty Transfer Materials (HTM). The dynamic behaviour of the hydrophobicity exhibited by insulator materials is due to their chemical composition. Different processes such as oxidation, hydrolysis, migration of low molecular weight compounds, formation of complex compounds between e.g. siloxanes and wa

36、ter, rotation of flexible polymer chains, inter- and intra-molecular rearrangements, microbiological growth, deposition of contaminants, adhesion and encapsulation of contaminant particles, may take place at different rates, depending on material and ambient conditions. Thus hydrophobicity along and

37、 around an insulator can vary, due to differences in the exposure to solar radiation, rain, corona discharges, deposited pollution, etc. Therefore, hydrophobicity of insulators is usually measured on several separate areas of the insulator. Measurement of the hydrophobicity of a surface is readily p

38、erformed in the laboratory on well defined, homogeneous, smooth and planar surfaces of prepared specimens. In the case of insulators, for which non-destructive measurements are usually required (and where cut-out of material samples is usually not desired), these conditions do not exist and measurem

39、ent with high precision is a difficult task. This is especially true when the measurement has to be performed on an insulator installed in an overhead line, substation or even in a high voltage test set-up in the laboratory. Previously wettability class (WC) was used as equivalent technology. PD IEC

40、/TS 62073:2016IEC TS 62073:2016 IEC 2016 7 GUIDANCE ON THE MEASUREMENT OF HYDROPHOBICITY OF INSULATOR SURFACES 1 Scope The methods described in this technical specification can be used for the measurement of the hydrophobicity of the shed and housing material of composite insulators for overhead lin

41、es, substations and equipment or ceramic insulators covered or not covered by a coating. The obtained value represents the hydrophobicity at the time of the measurement. The object of this technical specification is to describe three methods that can be used to determine the hydrophobicity of insula

42、tors. The determination of the ability of water to wet the surface of insulators may be useful to evaluate the condition of the surface of insulators in service, or as part of the insulator testing in the laboratory. 2 Terms and definitions For the purposes of this document, the following definition

43、s apply. 2.1 hydrophobicity state of a surface with a low surface tension and thus is water-repellent 2.2 hydrophilicity state of a surface with a high surface tension and thus is wetted by water (in the form of a film) 2.3 surface tension region of finite thickness (usually less than 0,1 m) in whic

44、h the composition and energy vary continuously from one bulk phase to the other Note 1 to entry: The pressure (force field) in the interfacial zone has a gradient perpendicular to the interfacial boundary. A net energy is required to create an interface (surface) by transporting the matter from the

45、bulk phase to the interfacial (surface) zone. The reversible work required to create a unit interfacial (surface) area is the surface tension and is defined thermodynamically as follows: T,P,n A G = where is the surface (interfacial) tension or surface energy; G is the Gibbs free energy of the total

46、 system; A is the surface (interfacial) area; T is the temperature; P is the pressure; n is the total number of moles of matter in the system. The surface tension ( ) is usually expressed in mN/m (1 mN/m = 1 dyn/cm). PD IEC/TS 62073:2016 8 IEC TS 62073:2016 IEC 2016 2.4 static contact angle angle of

47、 a drop of liquid resting on the surface of a solid, and a gas is in contact with both, the forces acting at the interfaces are in balance Note 1 to entry: These forces are due to surface tensions acting in the direction of the respective surfaces. From Figure 1 it follows that: SL GS s GL cos = whe

48、re sis the static contact angle of the edge of the drop with the solid surface, GLis the surface tension of the gas-liquid interface, GSis the surface tension of the gas-solid interface, and SLis the surface tension of the solid-liquid interface. Note 2 to entry: The above equation (Youngs equation)

49、 is only valid for ideal and smooth surfaces. Figure 1 Definition of the static contact angle The right side of the above equation (the difference between the surface tensions of the gas-solid and the solid- liquid interfaces) is defined as the surface tension of the solid surface. It is not a fundamental property of the surface but depends on the interaction between the solid and a particular environment. When the gas is air satur