Analysis and Summary of Common Construction Issues in PV Power Plants

With the increasing maturity of solar power generation technology,   photovoltaic (PV) systems are being applied more widely. Building safe   and efficient PV power plants hinges on high-quality construction. Based on recent field maintenance and accumulated   experience, this edition focuses on analyzing and summarizing common   issues encountered during PV construction, providing references for   standardized practices.

I. Classification and Analysis of Common Issues

1. Component Installation Issues

Component Damage: Stepping on panels or placing heavy objects   during construction can easily cause cell micro-cracks, potentially leading to panel breakage or failure in   severe cases. Additionally, improperly secured PV cables can   suffer abrasion and insulation damage due to friction.

Connection Hazards: Loose mating of string connectors is a   primary risk factor for inducing DC arcing.

Improper Clamp Installation:

Using a single clamp to secure two panels (each panel   should be independently fixed at both ends).

Failure to replace corroded clamp washers promptly.

Clamps placed crookedly, offset, or causing uneven pressure   distribution, leading to localized stress points on panels.

Clamp bolts used without spring washers or inadequately   tightened.

Improper Siting: Installation in areas with severe shading or   pollution is strictly prohibited. If site obstacles deviate from   the design drawings, immediate communication with the design team   for plan adjustment is essential.

2. Cable Construction Issues

DC-Side Issues (High Incidence, High Risk):

Connector Cross-Mating: Differences in specifications, dimensions, and   tolerances between connectors from different manufacturers   can lead to increased contact resistance, abnormal   temperature rise, and compromised ingress protection (IP)   ratings when forcibly mated, significantly impacting plant   efficiency and safety (ranked among the top three failure   causes in TÜV Rheinland FMEA assessments).

Improper MC4 Plug Termination: Dedicated crimping tools   must be used; pliers or side cutters are strictly prohibited to ensure secure and reliable connections.

Cable Routing and Management:

Failure to strictly distinguish positive and negative   cables using red/black colors or to install sleeve   markers labeled "+" and "-", increasing the risk of polarity reversal.

Cables and connectors left loose or hanging, not   secured to the mounting structure or panel backsheet,   increasing damage risk.

Exposed cable runs lacking conduit protection or   cable trays, where physical damage can cause insulation breaches, posing safety hazards.

AC-Side Issues:

Incorrect Cable Selection: Failure to strictly adhere to   cable specifications recommended in inverter and other   equipment manuals.

Improper Termination: Incorrect stripping length,   insufficient contact area between terminal and conductor   core, failure to tighten terminals to the torque specified in manuals (e.g., models like G6-GR1P(7-8)K2 have clear requirements).

Insufficient Routing Management: Similar to DC side, issues   include inadequate cable securing and protection.

3. Inverter Construction Issues

Improper Location: Installation in damp, poorly ventilated,   direct sunlight exposed areas, or environments prone to vibration, instead of suitable locations like outdoor walls, rooftops, or   equipment rooms.

Insecure Mounting: Undersized or unstable mounting brackets can   cause the inverter to tilt or sway under wind load or other forces.

Inadequate Safety Clearance: Insufficient distance from surrounding equipment or structures, lack of protective measures, increasing   risk of accidental contact or safety hazards, and failure to   effectively prevent sun exposure or snow/rain accumulation.

Cable Stress Impact: Failure to account for the inherent spring   force/stress of AC cables during installation can lead to   terminal loosening or detachment over time.

4. Other Critical Construction Issues

Lack of Grounding & Lightning Protection: Failure to install   effective bonding jumpers between panels, between panels and   cable trays, or at inverters/other equipment as required,   creating significant electrical safety hazards. Special attention   to the grounding specifics of PV arrays and inverters is crucial,   especially in commercial & industrial (C&I) projects.

Oversights in Project Closeout:

Debris left above/below panels not cleared, affecting   aesthetics and potentially causing shading (hot spots) or   even fire hazards (e.g., cardboard, plastic film).

Failure to identify and address waterproofing and drainage   issues (e.g., blocked drainage holes, roof damage).

Unsealed Critical Penetrations: Failure to effectively seal   openings using fire-stop putty at locations like cable tray/conduit entries,   combiner box cable entries, and conduit entry/exit points.

II. Summary

Standardized construction is fundamental to ensuring the safe, efficient, and long-lasting operation of PV power plants. This article systematically reviews common construction problems and their potential risks, focusing on   core aspects: component installation, cable routing (DC and AC sides),   inverter installation, grounding & lightning protection, and project   closeout. Through in-depth analysis of these issues, it aims to deliver clear standardized   guidelines for PV practitioners, promoting continuous improvement and   standardization of construction practices. Ultimately, this safeguards   the long-term stable operation of power plants, maximizing power generation and   return on investment.