Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
This standard replaces DL/T 627-2012 Room temperature vulcanized silicon rubber anti-pollution coating for insulators, with respect to which, the following main technical changes have been made:
——the term "RTV anti-pollution coating" is redefined by supplementing the descriptions on composition and function as canceling the classification requirements of ordinary RTV-I and strengthened RTV-II products;
——the term "surface dry time” is added;
——the requirements of "solids content” are deleted, and the "vulcanized coating density" and its measuring method are added;
——the requirements of "viscosity" are deleted for only affecting the construction;
——the requirements of "relative permittivity and loss tangent tanδ" are deleted, and these parameters shall be provided by the manufacturer;
——the requirements of "adhesion test by scratch method" are deleted, and adhesion test by shear strength method is retained by modifying the test procedures;
——the requirements of "abrasion resistance" are deleted, and it is stipulated that abrasion resistance shall be considered for coatings used in windy and desert areas with indicators agreed upon the supplier and the purchaser;
——”combustibility" is reduced from "FV-0" to "FV-I";
——the requirements of "dirt withstand voltage performance" and "5,000h artificial accelerated aging test” are deleted;
——the quantity of sample in a batch is changed from "no greater than 500kg" to "no greater than 2,000kg", and a piece-by-piece secondary sampling scheme is added for result judgment;
——the items for sample test and type test are modified;
——the requirements of "acceptance" and "construction" are deleted, and these requirements are included in DL/T 5727 Technical specification of room temperature vulcanized silicon rubber anti-pollution coating field execution for insulators;
——Annex A "General requirements for specimen preparation" and Annex C "Method for measuring hydrophobicity of RTV coating" are added.
This standard was proposed by China Electricity Council.
This standard is under the jurisdiction of the Technical Committee on Insulator of Standardization Administration of Power Industry (DL/TC 16).
Any comments or suggestions during the implementation of this standard may be fed back to the Standardization Center of the China Electricity Council (No.1, 2nd Lane, Baiguang Road, Beijing, 10076, China).
Room temperature vulcanized sillicon rubber anti-pollution coating for insulators
1 Scope
This standard specifies the basic technical requirements, inspection rules, packaging and storage, selection principles, operation and maintenance, and technical management of room temperature vulcanized sillicon rubber anti-pollution coating for insulators.
This standard is applicable to room temperature vulcanized sillicon rubber anti-pollution coating (hereinafter referred to as RTV anti-pollution coating) for power transmission and transformation equipment used in AC and DC overhead power lines, power plants, substations and converter stations.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 529 Rubber vulcanized or thermoplastic - Determination of tear strength (Trouser, angle and crescent test pieces)
GB/T 1408.1 Insulating materials - Test methods for electric strength - Part 1: Tests at power frequencies
GB/T 1692 Vulcanized rubber - Determination of the insulation resistivity
GB/T 2900.5 Electrotechnical Terminology - Insulating Solids, Liquids and Gases
GB/T 2900.8 Electrotechnical Terminology - Insulators
GB/T 2900.19 Electrotechnical terminology - High-voltage test technique and insulation co-ordination
GB/T 6553 Electrical Insulating Materials used under Severe Ambient Conditions - Test Methods for Evaluating Resistance to Tracking and Erosion
GB/T 6753.2 Paints and varnishes - Surface-drying test - Ballotini method
GB/T 9274 Paints and varnishes - Determination of resistance to liquids
GB/T 10707 Rubber - Determination of the burning behavior
GB/T 20642 Impulse puncture test in air on insulators for overhead lines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.5, GB/T 2900.8 and GB/T 2900.19 as well as the following apply.
3.1
RTV anti-pollution coating
monocomponent coating prepared by mixing base glue, filler, auxiliaries and solvent, which can be vulcanized into a thin film layer at room temperature to improve the anti-pollution performance of insulators or power transmission and transformation equipment
Note: The base glue generally refers to hydroxyl-terminated polydimethylsiloxane (HPDMS), or synthetic silicone resin or other organosilicon polymers in some cases. The filler is mainly composed of white carbon black, aluminum hydroxide, ferric hydroxide, etc. Auxiliaries are mainly composed of crosslinking agent, catalyst, accelerant, silane coupling agent, etc. Solvent is mainly composed of No.120 solvent gasoline, tetrachloroethylene, dichlorofluoroethane, etc.
3.2
RTV coating
thin film formed by RTV anti-pollution coating through vulcanization at room temperature
3.3
self-cleaning
ability of RTV coating of protecting its surface from adhering contamination
3.4
surface dry time
the time required for changing the liquid coating to thin, soft and non-sticky film under certain conditions
4 Basic technical requirements
4.1 Physical and chemical properties
4.1.1 Appearance
The coating shall be at viscous liquid state with uniform color and free from obvious mechanical impurities and floccule before vulcanization.
The surface of vulcanized RTV coating shall be flat, smooth and free of bubbles.
See Annex A for the preparation method and requirements of RTV coating specimen.
4.1.2 Vulcanized coating density
After vulcanization, the coating density is not greater than 1.28g/cm3.
See Annex B for test methods.
4.1.3 Surface dry time
The surface dry time is not greater than 45min [temperature of 23±2℃, relative humidity of (50±10)%].
4.1.4 Hydrophobicity
The hydrophobicity of RIV coating shall meet the following requirements:
a) initial classification characteristics of hydrophobicity: HC1~HC2;
b) hydrophobicity weakening characteristics: HC3~HC4;
c) hydrophobicity recovery characteristics: HC2~HC3;
d) hydrophobic migration characteristics: HC2~HC3;
See Annex C for the method for measuring hydrophobicity of RTV coating.
4.1.5 Combustibility
Not lower than Grade FV-I.
4.1.6 Corrosion resistance
4.1.6.1 Resistance to chemical reagent
The coating shall be free from peeling, wrinkling, blistering or discoloration after being socked in acid, alkali or salt reagents (concentration of 3%) at 25℃ for 24h.
4.1.6.2 Resistance to oil
The coating shall be free from peeling, wrinkling, blistering or discoloration after being socked in transformer oil at 100℃ for 24h.
4.2 Electrical performance
Electrical performance shall meet the following requirements:
a) The volume resistivity shall not be less than 1.0×1012Ω·m.
b) The dielectric strength E shall not be less than 18kV/mm (specimen thickness of 1±0.1mm).
c) The resistance to tracking and erosion shall not be inferior to Grade TMA2.5;
d) Impulse breakdown performance: for the disc-shaped suspension porcelain (glass) insulators with RTV coating, the impulse breakdown performance shall meet the requirements of GB/T 20642. See Annex D for the test method and judgment criteria, which shall be agreed upon the negotiation of the supplier and the purchaser.
Note: The relative permittivity and loss tangent shall be provided by the manufacturer.
4.3 Mechanical property
Mechanical property shall meet the following requirements:
a) The adhesion of the RTV coating to the surface of glass plate shall be tested with shear strength method, which shall not be less than 3.0MPa, and see Annex E for the test method.
b) The tearing strength (rectangular specimen, without cutting) shall not be less than 7.0kN/m.
c) The tensile strength (dumbbell specimen type 1) shall not be less than 3.0MPa.
d) The elongation at break (dumbbell specimen type 1) shall not be less than 200%.
Note: Abrasion resistance shall be considered for coatings used in windy and desert areas with indicators agreed upon the supplier and the purchaser;
4.4 Self-cleaning
The self-cleaning performance shall not be lower than Grade 2 when evaluating with ballotini method; the film shall not be adsorbed on the coating surface when evaluating with film method. See Annex F for the test method.
Ballotini method is used for indoor evaluation, and film method is used for on-site evaluation.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Basic technical requirements
5 Inspection rules
6 Packaging and storage
7 Selection principles
8 Operation and maintenance
9 Technical management
Annex A (Informative) General requirements for specimen preparation
Annex B (Normative) Method for measuring vulcanized coating density
Annex C (Normative) Method for measuring hydrophobicity of RTV coating
Annex D (Informative) Test method for impulse breakdown voltage
Annex E (Normative) Test method for shear strength
Annex F (Normative) Test method for self-cleaning
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.
This standard replaces DL/T 627-2012 Room temperature vulcanized silicon rubber anti-pollution coating for insulators, with respect to which, the following main technical changes have been made:
——the term "RTV anti-pollution coating" is redefined by supplementing the descriptions on composition and function as canceling the classification requirements of ordinary RTV-I and strengthened RTV-II products;
——the term "surface dry time” is added;
——the requirements of "solids content” are deleted, and the "vulcanized coating density" and its measuring method are added;
——the requirements of "viscosity" are deleted for only affecting the construction;
——the requirements of "relative permittivity and loss tangent tanδ" are deleted, and these parameters shall be provided by the manufacturer;
——the requirements of "adhesion test by scratch method" are deleted, and adhesion test by shear strength method is retained by modifying the test procedures;
——the requirements of "abrasion resistance" are deleted, and it is stipulated that abrasion resistance shall be considered for coatings used in windy and desert areas with indicators agreed upon the supplier and the purchaser;
——”combustibility" is reduced from "FV-0" to "FV-I";
——the requirements of "dirt withstand voltage performance" and "5,000h artificial accelerated aging test” are deleted;
——the quantity of sample in a batch is changed from "no greater than 500kg" to "no greater than 2,000kg", and a piece-by-piece secondary sampling scheme is added for result judgment;
——the items for sample test and type test are modified;
——the requirements of "acceptance" and "construction" are deleted, and these requirements are included in DL/T 5727 Technical specification of room temperature vulcanized silicon rubber anti-pollution coating field execution for insulators;
——Annex A "General requirements for specimen preparation" and Annex C "Method for measuring hydrophobicity of RTV coating" are added.
This standard was proposed by China Electricity Council.
This standard is under the jurisdiction of the Technical Committee on Insulator of Standardization Administration of Power Industry (DL/TC 16).
Any comments or suggestions during the implementation of this standard may be fed back to the Standardization Center of the China Electricity Council (No.1, 2nd Lane, Baiguang Road, Beijing, 10076, China).
Room temperature vulcanized sillicon rubber anti-pollution coating for insulators
1 Scope
This standard specifies the basic technical requirements, inspection rules, packaging and storage, selection principles, operation and maintenance, and technical management of room temperature vulcanized sillicon rubber anti-pollution coating for insulators.
This standard is applicable to room temperature vulcanized sillicon rubber anti-pollution coating (hereinafter referred to as RTV anti-pollution coating) for power transmission and transformation equipment used in AC and DC overhead power lines, power plants, substations and converter stations.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 529 Rubber vulcanized or thermoplastic - Determination of tear strength (Trouser, angle and crescent test pieces)
GB/T 1408.1 Insulating materials - Test methods for electric strength - Part 1: Tests at power frequencies
GB/T 1692 Vulcanized rubber - Determination of the insulation resistivity
GB/T 2900.5 Electrotechnical Terminology - Insulating Solids, Liquids and Gases
GB/T 2900.8 Electrotechnical Terminology - Insulators
GB/T 2900.19 Electrotechnical terminology - High-voltage test technique and insulation co-ordination
GB/T 6553 Electrical Insulating Materials used under Severe Ambient Conditions - Test Methods for Evaluating Resistance to Tracking and Erosion
GB/T 6753.2 Paints and varnishes - Surface-drying test - Ballotini method
GB/T 9274 Paints and varnishes - Determination of resistance to liquids
GB/T 10707 Rubber - Determination of the burning behavior
GB/T 20642 Impulse puncture test in air on insulators for overhead lines
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.5, GB/T 2900.8 and GB/T 2900.19 as well as the following apply.
3.1
RTV anti-pollution coating
monocomponent coating prepared by mixing base glue, filler, auxiliaries and solvent, which can be vulcanized into a thin film layer at room temperature to improve the anti-pollution performance of insulators or power transmission and transformation equipment
Note: The base glue generally refers to hydroxyl-terminated polydimethylsiloxane (HPDMS), or synthetic silicone resin or other organosilicon polymers in some cases. The filler is mainly composed of white carbon black, aluminum hydroxide, ferric hydroxide, etc. Auxiliaries are mainly composed of crosslinking agent, catalyst, accelerant, silane coupling agent, etc. Solvent is mainly composed of No.120 solvent gasoline, tetrachloroethylene, dichlorofluoroethane, etc.
3.2
RTV coating
thin film formed by RTV anti-pollution coating through vulcanization at room temperature
3.3
self-cleaning
ability of RTV coating of protecting its surface from adhering contamination
3.4
surface dry time
the time required for changing the liquid coating to thin, soft and non-sticky film under certain conditions
4 Basic technical requirements
4.1 Physical and chemical properties
4.1.1 Appearance
The coating shall be at viscous liquid state with uniform color and free from obvious mechanical impurities and floccule before vulcanization.
The surface of vulcanized RTV coating shall be flat, smooth and free of bubbles.
See Annex A for the preparation method and requirements of RTV coating specimen.
4.1.2 Vulcanized coating density
After vulcanization, the coating density is not greater than 1.28g/cm3.
See Annex B for test methods.
4.1.3 Surface dry time
The surface dry time is not greater than 45min [temperature of 23±2℃, relative humidity of (50±10)%].
4.1.4 Hydrophobicity
The hydrophobicity of RIV coating shall meet the following requirements:
a) initial classification characteristics of hydrophobicity: HC1~HC2;
b) hydrophobicity weakening characteristics: HC3~HC4;
c) hydrophobicity recovery characteristics: HC2~HC3;
d) hydrophobic migration characteristics: HC2~HC3;
See Annex C for the method for measuring hydrophobicity of RTV coating.
4.1.5 Combustibility
Not lower than Grade FV-I.
4.1.6 Corrosion resistance
4.1.6.1 Resistance to chemical reagent
The coating shall be free from peeling, wrinkling, blistering or discoloration after being socked in acid, alkali or salt reagents (concentration of 3%) at 25℃ for 24h.
4.1.6.2 Resistance to oil
The coating shall be free from peeling, wrinkling, blistering or discoloration after being socked in transformer oil at 100℃ for 24h.
4.2 Electrical performance
Electrical performance shall meet the following requirements:
a) The volume resistivity shall not be less than 1.0×1012Ω·m.
b) The dielectric strength E shall not be less than 18kV/mm (specimen thickness of 1±0.1mm).
c) The resistance to tracking and erosion shall not be inferior to Grade TMA2.5;
d) Impulse breakdown performance: for the disc-shaped suspension porcelain (glass) insulators with RTV coating, the impulse breakdown performance shall meet the requirements of GB/T 20642. See Annex D for the test method and judgment criteria, which shall be agreed upon the negotiation of the supplier and the purchaser.
Note: The relative permittivity and loss tangent shall be provided by the manufacturer.
4.3 Mechanical property
Mechanical property shall meet the following requirements:
a) The adhesion of the RTV coating to the surface of glass plate shall be tested with shear strength method, which shall not be less than 3.0MPa, and see Annex E for the test method.
b) The tearing strength (rectangular specimen, without cutting) shall not be less than 7.0kN/m.
c) The tensile strength (dumbbell specimen type 1) shall not be less than 3.0MPa.
d) The elongation at break (dumbbell specimen type 1) shall not be less than 200%.
Note: Abrasion resistance shall be considered for coatings used in windy and desert areas with indicators agreed upon the supplier and the purchaser;
4.4 Self-cleaning
The self-cleaning performance shall not be lower than Grade 2 when evaluating with ballotini method; the film shall not be adsorbed on the coating surface when evaluating with film method. See Annex F for the test method.
Ballotini method is used for indoor evaluation, and film method is used for on-site evaluation.
Contents of DL/T 627-2018
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Basic technical requirements
5 Inspection rules
6 Packaging and storage
7 Selection principles
8 Operation and maintenance
9 Technical management
Annex A (Informative) General requirements for specimen preparation
Annex B (Normative) Method for measuring vulcanized coating density
Annex C (Normative) Method for measuring hydrophobicity of RTV coating
Annex D (Informative) Test method for impulse breakdown voltage
Annex E (Normative) Test method for shear strength
Annex F (Normative) Test method for self-cleaning
