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 lines, 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.<\/p>\n
The object of this technical specification is to describe three methods that can be used to determine the hydrophobicity of insulators. 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.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 4<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | 1 Scope 2 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | Figures Figure 1 \u2013 Definition of the static contact angle Figure 2 \u2013 Definition of the advancing angle ((a) and the receding angle ((r) inside a liquid drop resting on an inclined solid surface <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 3 Methods for measurement of hydrophobic properties 3.1 General 3.2 Method A \u2013 Contact angle method 3.2.1 General 3.2.2 Equipment 3.2.3 Measurement procedure <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 3.2.4 Static contact angle measurements 3.2.5 Dynamic contact angle measurements 3.2.6 Evaluation Figure 3 \u2013 Measurements of the advancing angle ((a) and the receding angle ((r) by adding or withdrawing water from a droplet <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 3.3 Method B \u2013 Surface tension method 3.3.1 General 3.3.2 Safety precautions 3.3.3 Equipment and reagents <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 3.3.4 Measurement procedure 3.3.5 Evaluation 3.4 Method C \u2013 The spray method 3.4.1 General 3.4.2 Equipment <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 3.4.3 Measurement procedure 3.4.4 Evaluation <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 3.5 Documentation Tables Table 1 \u2013 Criteria for the determination of hydrophobicity class (HC) <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | Annex A (normative) Guidelines regarding the applicability and comments on the limitations of the different methods described in this technical specification A.1 General A.2 Typical results obtained with the three methods <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | Annex B (normative) Method A \u2013 Contact angle method Figure B.1 \u2013 Measurement of the advancing angle ((a) and the receding angle ((r) by using the captive bubble technique <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | Annex C (normative) Method B \u2013 Surface tension method Table C.1 \u2013 Concentrations of ethylene-glycol-monoethyl-ether (cellosolve), formamide mixtures used in measuring surface tension of insulator surfaces in the range 30\u00a0mN\/m to 56\u00a0mN\/m (T\u00a0=\u00a020\u00a0\u00b0C) <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | Table C.2 \u2013 Concentrations of distilled water and formamide mixture used in measuring surface tension of insulator surfaces in the range 58\u00a0mN\/m to 73\u00a0mN\/m (T\u00a0=\u00a020\u00a0\u00b0C) Table C.3 \u2013 Concentrations of distilled water and sodium chloride in mixtures used in measuring surface tension of insulator surfaces in the range 73 mN\/m to 82 mN\/m (T = 20 \u00b0C) <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Annex D (normative) Method C \u2013 Spray method Figure D.1 \u2013 Examples of surfaces with hydrophobicity class (HC) from 1 to 6 <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Guidance on the measurement of hydrophobicity of insulator surfaces<\/b><\/p>\n |