Analysis And Solutions of Durability Issues for Solar Racking Systems

Introduction: The Importance of PV Mounting Systems and Industry Challenges

Solar photovoltaic (PV) mounting systems are the core supporting structures of PV power generation systems, directly impacting the efficiency, safety, and return on investment of power plants. However, with the large-scale deployment of PV projects in recent years, issues such as material corrosion and insufficient strength have become increasingly prominent, leading to cases of rust, deformation, and even collapse within just 3-5 years of operation. These problems significantly affect the economic viability and reliability of PV plants.

Industry statistics indicate that approximately 15% of global PV power plants experience power generation losses or additional maintenance costs due to mounting system failures, with corrosion being particularly severe in coastal, high-humidity, and industrial pollution-prone areas. This article systematically analyzes typical failure cases of PV mounting systems, explores key technologies in material science, anti-corrosion processes, and structural optimization, and proposes practical industry solutions.

I. Corrosion Issues in PV Mounting Systems: Mechanisms, Case Studies, and Protection Strategies

1. Corrosion Failure Analysis of Steel Mounting Systems

(1) Typical Problems

• Lack of galvanization or insufficient zinc coating (<85μm): In humid, salty, or acidic environments, carbon steel mounting systems develop rust within 1-2 years, with wall thickness reduction exceeding 10%, leading to significant structural weakening.

• Weld corrosion: Some systems use welded joints without post-weld anti-corrosion treatment, causing preferential corrosion at weld zones and creating structural weak points.

(2) Case Study: Corrosion Incident at a Coastal PV Power Plant

• Project Background: A 100MW coastal PV plant used Q235 carbon steel mounting systems with a zinc coating of only 40μm.

• Issue Identified: After 18 months of operation, inspections revealed rust spots on nearly 30% of the mounting systems, with some columns corroded to a depth of 1mm, reducing load-bearing capacity by 25%.

• Root Causes:

• Substandard zinc coating failed to block chloride ion penetration.

• Open weld designs allowed rainwater infiltration, accelerating corrosion.

(3) Solutions

• Enhanced Galvanization Standards:

• Standard environments: Zinc coating ≥85μm (GB/T 13912).

• High-corrosion environments (coastal/industrial areas): Zinc coating ≥120μm or "hot-dip galvanizing + epoxy coating" dual protection.

• Optimized Welding Processes:

• Use TIG welding to reduce slag and apply zinc-rich paint post-weld.

• Promote bolted connections over welding to minimize corrosion risks.

2. Failure of Anodized Films on Aluminum Mounting Systems

(1) Problem Manifestations

• Insufficient anodized film thickness (<10μm): Prolonged UV exposure causes powdering and peeling, compromising protection.

• Galvanic corrosion: Direct contact between aluminum and stainless or carbon steel creates electrochemical corrosion due to potential differences.

(2) Solutions

• Enhanced Surface Treatment:

• Anodized film ≥15μm (e.g., 6061-T6 aluminum alloy).

• Fluorocarbon or PVDF coatings for improved weather resistance.

• Avoid Dissimilar Metal Contact:

• Use nylon spacers or insulating tape to isolate aluminum from steel.

• Prefer all-aluminum mounting systems.

II. Insufficient Material Strength: Optimization from Material Selection to Structural Design

1. Risks of Substandard Steel Materials

(1) Case Study: Beam Deformation in a Distributed PV Project

• Issue Description: Non-compliant steel (yield strength <200MPa) caused beam deflection exceeding L/150 under snow load, altering panel tilt and reducing output by 10%.

• Industry Standards Comparison:

  Material Type	GB/T 13912 Requirement	Actual Test Value
  Q235B Steel	Yield strength ≥235MPa	190MPa
  6061 Aluminum	Tensile strength ≥260MPa	210MPa

(2) Solutions

• Strict Material Qualification:

• Steel: Upgrade to Q355B (50% higher yield strength than Q235B).

• Aluminum: Prefer 6082-T6 (tensile strength ≥310MPa).

• Enhanced Load Calculations:

• Design for 30-year wind/snow loads.

• Consider dynamic loads (e.g., IEC 61400-2 for gust effects).

2. Structural Innovations

• Triangular Truss Designs: 40% higher wind resistance than single-axis systems.

• Adjustable Mounting Systems: Hydraulic/electric mechanisms for climate adaptability.

III. Industry Trends and Future Technologies

1. Advanced Anti-Corrosion Materials:

• Graphene coatings: Extend service life beyond 30 years.

• Fiberglass-reinforced polymer (FRP) mounts: Corrosion-resistant and lightweight.

2. Smart Monitoring:

• Embedded corrosion sensors for real-time health tracking.

• AI-powered drone inspections for rust/deformation detection.

3. Tighter Global Standards:

• EU EN 1090 certification for welding/corrosion resistance.

• US UL 2703 mandates wind load ratings.

Conclusion: Lifecycle Cost Optimization

Material selection, corrosion protection, and structural design must balance upfront costs with long-term maintenance. Examples:

• Coastal Plants: High-zinc coating (120μm) + periodic maintenance cuts lifecycle costs by 30%.

• High-Wind Areas: High-strength aluminum + truss designs reduce material use by 20% while enhancing safety.

Future advancements in materials and smart O&M will drive PV mounting systems toward longer lifespans, higher reliability, and lower maintenance costs, supporting sustainable global PV expansion.