Views: 0 Author: Site Editor Publish Time: 2026-03-19 Origin: Site
As core components in power systems, arresters are exposed outdoors year-round, with their silicone rubber housings subjected to multiple stressors including electric fields, UV radiation, temperature variations, and pollutants. Research indicates that silicone rubber aging manifests as chalking, hardening, cracking, and hydrophobic decline . In high-altitude areas, UV intensity increases by 10-12% per 1000m elevation, significantly accelerating aging . DC transmission projects show notably faster aging rates than AC systems . Therefore, in-depth research on aging mechanisms and protective technologies is crucial for grid reliability.
Long-term operating silicone rubber exhibits significant surface morphology changes. Scanning electron microscopy reveals gradual roughening of originally smooth surfaces, with micro-cracks and pits appearing . These morphological changes reduce material hydrophobicity, increasing surface water film formation probability. Concurrently, cross-linking density increases, causing material hardening and embrittlement, with elasticity modulus significant changes . Notably, surface chalking results from low molecular weight siloxane migration blockage due to cross-linked layer formation.
At the molecular level, silicone rubber aging involves complex chemical reactions. Fourier transform infrared spectroscopy shows decreased absorption peaks of Si-CH₃ and Si-(CH₃)₂ groups, while Si-O-Si bond absorption peaks widen , indicating main chain breakage and side group loss. Thermogravimetric analysis reveals reduced organic component content and increased inorganic residue proportion .
The aging process is dominated by cross-linking reactions. Under UV radiation, high-energy photons break silicone molecular chains, generating free radicals that initiate chain reactions. These radicals may recombine to form denser three-dimensional networks or react with oxygen to generate hydroxyl and carbonyl groups . Hydrophobic groups on material surfaces decrease, while hydrophilic groups increase, explaining hydrophobicity decline.
Actual operating environments involve multi-factor interactions. UV radiation increases surface temperature, accelerating thermal oxidation; pollutants absorb moisture, forming conductive paths that exacerbate corona discharge . DC electric fields cause unidirectional charge injection into materials, accelerating aging. DC transmission project data shows silicone rubber aging rates significantly exceed AC systems under equivalent conditions . This synergistic effect far exceeds single-factor aging sum, making multi-factor coupling a research focus.
Adding specific inorganic nanoparticles effectively enhances UV resistance. A patented technology incorporates 3-6 parts nano-TiO₂ and 3-7 parts ZnO into silicone rubber formulations . These semiconductor materials absorb high-energy UV photons, converting them to thermal energy through electron transitions. Nano-TiO₂ particularly shows excellent absorption below 400nm wavelength.
White carbon black (silica) addition not only reinforces but improves UV resistance. Adding 20-30 parts white carbon black significantly increases tear strength . Nano-silica's large specific surface area provides good UV scattering, while interface effects with silicone rubber enhance aging resistance.
Organic UV absorbers like benzophenones (3-6 parts) effectively capture UV energy through molecular structure isomerization . These additives preferentially absorb UV before silicone molecular chains, dissipating energy as heat. Unlike inorganic absorbers, organic stabilizers dissolve molecularly in silicone rubber, providing uniform protection.
Optimal UV protection requires synergistic multi-component systems. Combining nano-TiO₂, benzophenone, and iron oxide red (2-5 parts) achieves superior performance through different UV absorption bands complementing each other . Iron oxide red also provides coloration while enhancing UV absorption, particularly valuable in high-altitude applications.
PRTV (Room Temperature Vulcanized silicone rubber) coatings are primary anti-contamination flashover materials. They exhibit excellent hydrophobicity with contact angles exceeding 110° and demonstrate rapid, balanced hydrophobicity transfer . This transfer mechanism allows pollutant layers to gain hydrophobicity within hours, preventing continuous water films.
PRTV coatings incorporate nano-scale fillers uniformly distributed in silicone networks, blocking micropores above 20nm and reducing moisture permeability . Mechanical properties include high modulus, strength, and adhesion, maintaining integrity under electrical and mechanical stresses.
Next-generation coatings utilize fluorosilicone rubber matrices with exceptional chemical stability . Nano-filler reinforcement creates dense cross-linked structures with high surface smoothness, enhancing self-cleaning where pollutants are easily washed by rain.
Superhydrophobic coatings achieve contact angles exceeding 150° and sliding angles below 5° through micro-nano hierarchical structures . These coatings demonstrate excellent temperature resistance, maintaining superhydrophobicity under extreme conditions while resisting UV and ozone aging.
Field applications show RTV/PRTV coatings increase contamination flashover voltage by over 2 times . Treated arresters maintain performance in heavily polluted areas with extended maintenance intervals. Coated surfaces resist ice accumulation and accelerate de-icing in cold regions .
Traditional assessment includes visual inspection, hydrophobicity classification (HC1-HC7), and static contact angle measurement . However, these methods only capture surface manifestations. Advanced techniques provide quantitative parameters: scanning electron microscopy for microstructure observation; thermogravimetric analysis for component content; FTIR for chemical group changes; thermally stimulated current for trap parameters .
Researchers propose using hardness, hydrophobicity classification, and FTIR as characteristic quantities for aging assessment based on regression analysis . These parameters enable quantitative aging evaluation and remaining life prediction.
Innovative pulsed laser technology removes aged silicone rubber layers without substrate damage . Precise energy control strips degraded material while preserving intact underlying silicone, exposing fresh material with full hydrophobicity. This technology applies to arresters, insulators, and cable accessories, significantly extending service life.
Silicone rubber arrester housings undergo complex aging processes under multi-factor synergy, primarily involving main chain breakage and cross-linking reactions leading to hydrophobicity decline and performance degradation. Adding UV absorbers and stabilizers effectively delays aging, while anti-contamination coatings provide additional protection. Quantitative assessment methods enable condition-based maintenance, and laser repair technology offers new approaches for extending equipment life.
