In an outdoor photovoltaic system, a fuse needs to be exposed to heat, humidity, ultraviolet light, sand and dust for a long time. Their waterproof, dustproof, and UV-resistant properties directly affect the safety and reliability of the system. The following are the main technical measures and design principles to avoid failure due to environmental factors:
I.Waterproof design: prevents moisture from entering, short circuit or insulation failure
High sealing shell: Made of weatherproof engineering plastics (e.g. PC/ABS alloys) or metallic materials (e.g. stainless steel), the joint is reduced by integrated injection molding or precision die-casting and combined with silicone rubber sealing rings to achieve protection of IP65 or above (dust and water resistance).
Ventilation Valve Design: Install a breathable membrane (such as GORE-TEX) on the top or side of the fuse to balance internal and external pressure differences, prevent condensation water from accumulating inside, and prevent rain and dust from entering.
Drainage Channels and Inclined Installation: Drains are designed at the bottom of the shell at an angle a 5℃-10℃ inclination angle to avoid water accumulation.
Encapsulation process: Apply epoxy resin or silicone to key parts (such as contacts, arc extinguishing chambers, etc.) inside the fuse to form a completely sealed layer to prevent moisture from entering.
Dual insulation structure: Insulation bushing or three coats of paint (moisture, salt, mold resistance) are added between the conductive components and housing to increase creep distance and electrical clearance.
ii. Dust protection design: prevents dust from entering and affecting Contact Reliability
Dust Filter: Installation of removable metal/nylon dust filter mesh with aperture <= 0.5 mm at air intake or cooling hole. Wash regularly to maintain ventilation efficiency.
Maze-type Sealing: Through the design of curved channels inside the shell, dust cannot reach the core parts directly after multiple refractions, and is combined with the seal ring to block the direct invasion path.
Wear-resistant interface design
Silver contacts: contact surface with silver or silver alloys to improve conductivity and reduce oxidation, reducing the risk of increased contact resistance due to dust adhesion.
Self-cleaning structure: Spring contact or sliding contacts design. During the operation of the fuse, it automatically removes surface dirt through mechanical friction.
III. UV-Resistant Design: Slow Material Aging and Performance Degradation
UV stabilizer addition: carbon black, zinc oxide or benzodiazole benzotriazole-based UV absorbers is added to the plastic housing to absorb or reflect ultraviolet light and inhibit molecular chain breakage.
Metal exterior treatment: stainless steel exterior is polished or sanded to reduce light reflection; aluminum alloy housing is anodized to form a dense oxide film that blocks ultraviolet light.
UV-resistant glass/PC: If the fuse has an observation window or indicator light, transparent materials containing UV-inhibitors with a a transmittance >= 85% and blocking more than 99% of UV-A/B.
Sunshade design: Install a sunshade over the observation window to reduce the amount of direct sunlight.
IV. INTRODUCTION Comprehensive Environmental Adaptability Design
Wide-range working temperature
High-temperature resistant materials: Select plastic or silicone seals with a temperature resistance grade >= 125℃ to ensure no deformation or cracking at extreme temperatures ranging from -40℃ to +85℃.
Thermal expansion compensation: through elastic sealing rings or bellows structure absorbs the material heat expansion and shrinkage of the stress, preventing sealing failure.
Triple-protection coating: epoxy resin or polyurethane triple-protection coating is sprayed on metal components to form a dense protective layer against salt spray and acid rain corrosion.
Stainless Steel Material: 316L stainless steel shells is preferred in coastal or heavily polluted areas. The increase of molybdenum content improves the corrosion resistance of chlorine ions.
Impact-resistant Enclosure: Increasing the thickness of the walls or design reinforcement ribs to improve resistance to hail and dust storms.
Anti-misoperation Cover: Install a lockable protective cover to prevent unauthorized access to fuses, animal bites or foreign objects.
