Commercial Solar PV Maintenance Inspection

Overview

A comprehensive maintenance inspection was conducted on a commercial solar photovoltaic (PV) system installed at a mid-sized manufacturing plant in Huntingdon Cambridgeshire. The system, installed five years ago, has a capacity of 60kW and spans over 2430 square meter of rooftop space. This inspection was part of the plant’s regular maintenance schedule, aimed at ensuring optimal performance and longevity of the system and for fire safety compliance.

Objectives

• Assess the overall health and performance of the solar PV system.
• Identify and rectify any potential issues affecting energy output.
• Ensure compliance with safety and regulatory standards.
• Prolong the system’s lifespan and maximize return on investment.

Inspection Process

1. Visual Inspection

• Modules: A thermographic aerial drone was used to visually inspect all PV modules for physical damage, discoloration, and soiling.
• Mounting Systems: The integrity of the mounting structures was checked for corrosion, loose fittings, and structural stability.
• Wiring and Connectors: Inspection of electrical connections for signs of wear, corrosion, and secure attachment.
• Inverters: External inspection of inverters for any signs of overheating, dust accumulation, or damage.

2. Performance Testing

• IV Curve Tracing: Technicians used specialized equipment to trace the current-voltage (IV) characteristics of a sample set of modules to identify underperforming units.
• Thermographic Imaging: Infrared cameras were used to detect hot spots and anomalies that could indicate malfunctioning cells or connections.
• Energy Output Comparison: The actual energy output was compared against expected performance metrics considering irradiance and temperature data.

3. Cleaning and Maintenance

• Module Cleaning: All PV modules were cleaned to remove dust, bird droppings, and other debris that could hinder sunlight absorption.
• Vegetation Control: Any vegetation encroaching on the system was trimmed back to prevent shading.
• Electrical Maintenance: Loose connections were tightened, and any corroded parts were replaced. Fuses and surge protectors were checked and replaced if necessary.

4. Safety and Compliance Checks

• Grounding System: Ensured all components were properly grounded to prevent electrical hazards.
• Signage and Labels: Verified that all safety signage and labelling were intact and visible.
• System Testing: Conducted a series of safety tests to ensure the system was operating within safe parameters.

Findings

• Module Performance: Approximately 2% of the modules were identified as underperforming due to microcracks and needed replacement.
• Wiring Issues: Minor issues with wiring, such as loose connectors and minor corrosion, were found and rectified.
• Inverter Problems: One of the ten inverters was found to be malfunctioning and was replaced.
• Cleaning Impact: Post-cleaning performance tests showed a 5% increase in system efficiency, demonstrating the significant impact of soiling on energy output.

Recommendations

• Regular Cleaning: Implement a more frequent cleaning schedule to prevent soiling-related efficiency losses.
• Enhanced Monitoring: Upgrade the monitoring system to provide real-time data on module and string performance for early detection of issues.
• Preventive Maintenance: Schedule preventive maintenance bi-annually instead of annually to catch potential issues before they impact performance.
• Training: Conduct regular training sessions for the maintenance team on the latest PV system technologies and maintenance practices.

Conclusion

The inspection highlighted the critical importance of regular maintenance for commercial solar PV systems. By addressing minor issues and optimizing the system, the plant not only improved immediate performance but also took steps to ensure long-term reliability and efficiency. This case study underscores that a proactive maintenance approach can significantly enhance the return on investment in solar energy systems.