Views: 0 Author: Site Editor Publish Time: 2026-03-18 Origin: Site
In a photovoltaic (PV) power generation system, PV modules, inverters, and cables are core operating units. Once a fault occurs, it will not only lead to a decline in power generation efficiency but also may cause equipment damage and potential safety hazards. Especially for distributed PV power stations, the fault rate is relatively high due to the influence of environmental factors and installation standards. This article focuses on common faults of these three core components and provides quick troubleshooting and solutions combined with practical scenarios, helping power station operation and maintenance personnel and owners efficiently handle problems and ensure the stable operation of the power station.
I. PV Module Faults: Core Causes of Sharp Decline in Power Generation Efficiency
PV modules are the key to converting solar energy into electrical energy. Their faults are mostly related to environmental erosion, improper installation, and equipment aging, mainly manifested in abnormal power generation and appearance damage. The specific troubleshooting and solutions are as follows.
(I) Common Fault 1: Significant Decline in Module Power Generation Efficiency
Fault Performance: In the same power station, the power generation of the branch where some modules are located is much lower than that of modules of the same specification, and local high-temperature areas can be seen on the module surface through infrared thermal imaging detection.
Troubleshooting Steps:
First, check the module surface: whether it is covered by dust, bird droppings, or leaves. After cleaning the obstacles in the morning or evening, if the power generation is restored, it is an occlusion problem; if not improved, proceed to the next step.
Detect module electrical parameters: Use a DC clamp meter to measure the input current of each PV string connected to the same DC combiner box. If the current deviation of a certain string exceeds 5%, it is likely that there is a fault in that string of modules.
Infrared thermal imaging detection: Focus on checking whether the modules have hidden cracks or hot spot effects. If there is glass breakage, backsheet burning, or local high-temperature points, the module can be determined to be invalid.
Solutions:
Daily cleaning: Wipe with a dry or damp soft cloth, avoid corrosive solvents. Choose the time when solar irradiance is below 200 W/㎡ for cleaning to avoid module damage due to excessive temperature difference.
Disposal of faulty modules: Minor faults such as hidden cracks and hot spots can be repaired by contacting the manufacturer; serious faults such as glass breakage, backsheet burning, and local short circuits require timely replacement of modules of the same specification. When replacing, ensure that the module frame is well grounded with the mounting structure, and the contact resistance ≤ 4 Ω.
(II) Common Fault
Fault Performance: Module glass breakage, backsheet deformation, junction box burning and loosening, and poor terminal contact.
Troubleshooting Steps:
Visual inspection: Check the appearance of each module one by one. If there are glass cracks, backsheet bulging/discoloration, or junction box deformation, the fault is directly determined.
Wiring inspection: Gently shake the connecting wires between the junction box and the terminals. If there is looseness, overheating, or insulation layer damage, further detection is required.
Solutions:
Appearance damage: Minor scratches can be protected; severe damage requires direct replacement; backsheet bulging and burning require immediate shutdown and replacement of modules to prevent leakage risks.
Abnormal wiring: Re-tighten the terminal bolts, replace damaged connecting wires and junction boxes, and ensure the junction box is well sealed to avoid water vapor intrusion causing short circuits.
(III) Common Fault 3: Abnormal Module Grounding
Fault Performance: Leakage alarm occurs during module operation, and the measured value of grounding resistance is not up to standard.
Troubleshooting Steps: Use professional instruments to detect the contact resistance between the module metal frame and the grounding device. If the contact resistance > 4 Ω, it is abnormal grounding.
Solutions: Clean the rust and dirt at the connection between the module frame and the mounting structure, and re-tighten the connecting bolts; if the anti-corrosion coating of the bracket is damaged, touch it up in time to ensure firm and reliable grounding.
II. Inverter Faults: Key Reasons for Sudden Shutdown of the Power Station "Heart"
The inverter is the core connecting the PV system and the power grid, responsible for converting DC power into AC power. Its faults directly lead to power station shutdown or abnormal power generation. Common problems are concentrated in three categories: failure to start, abnormal output, and frequent alarms.
(I) Common Fault 1: Inverter Cannot Start
Fault Performance: No display or start signal after power-on, or tripping immediately after startup.
Troubleshooting Steps:
Power supply and wiring inspection: Check whether the input side (DC side) of the inverter is powered off, whether the fuse and circuit breaker of the DC combiner box are tripped; check whether the DC bus wiring is loose and whether the positive and negative poles are reversed.
Environment and heat dissipation inspection: Check whether the inverter installation environment has poor ventilation and excessively high temperature (exceeding 40℃), whether the cooling fan is running normally, and whether the interior is dusty and blocks the air duct.
Fault code verification: Check the fault code on the inverter display or monitoring system, and judge the fault type (such as overvoltage, undervoltage, overheating) according to the manual.
Solutions:
Wiring and power supply problems: Re-tighten the DC side wiring, correct the reverse connection of positive and negative poles, and restore the tripped circuit breaker and fuse.
Heat dissipation and environment problems: Clean the dust inside the inverter, install additional ventilation fans or adjust the installation position to reduce the ambient temperature; if the startup fails due to overheating, restart after the temperature drops to the normal range.
Faults corresponding to codes: Handle according to the requirements of the manual. For example, overvoltage/undervoltage needs to check the grid voltage or DC side input voltage, and contact the manufacturer to check the internal circuit of the inverter.
(II) Common Fault 2: Abnormal Inverter Output (Unstable Power, Grid-Connection Failure)
Fault Performance: The inverter output power fluctuates greatly, frequent disconnection from the grid, or failure to connect to the grid for power generation. The grid-side detection shows abnormal voltage and frequency.
Troubleshooting Steps:
Grid parameter detection: Use a multimeter to measure the voltage and frequency at the AC output terminal of the inverter. If it exceeds the grid-connection standard (voltage deviation ±7%, frequency deviation ±0.2Hz), it is determined to be a grid-side problem.
Module side inspection: Check whether the PV string on the DC side corresponding to the inverter is blocked or faulty. If the module power generation is abnormal, it will lead to insufficient input power of the inverter and cause output fluctuation.
Inverter internal inspection: Check whether the AC side circuit breaker and contactor of the inverter are flexible and reliable, whether the Surge Protective Device (SPD) is invalid, and whether the internal capacitor is aged and bulging.
Solutions:
Grid-side problems: Contact the power supply department to troubleshoot grid faults, and restart the inverter after the grid parameters return to normal; if it is a local grid fluctuation, a voltage stabilizer can be installed.
Module-side problems: Prioritize troubleshooting module occlusion and faults, and restore the inverter operation after repairing the modules.
Inverter internal problems: Replace the invalid SPDs and aged capacitors, and tighten the AC side wiring; if it cannot be handled by yourself, contact the inverter manufacturer for professional maintenance.
(III) Common Fault 3: Frequent Inverter Alarms and Shortened Service Life
Fault Performance: The inverter continuously has overheating, overcurrent, and insulation fault alarms, and the internal components age accelerated after long-term operation.
Troubleshooting Steps:
Daily inspection: Record the alarm frequency and time period, and analyze it in combination with the ambient temperature and module power generation.
Internal detection: Open the inverter shell, check whether the cooling fan is stuck, whether the internal lines are oxidized, and whether the wiring terminals are loose.
Solutions:
Regular maintenance: Clean the dust inside the inverter every six months, lubricate or replace the cooling fan; tighten all wiring terminals to prevent oxidation and loosening.
Alarm handling: For overheating alarms, strengthen ventilation and heat dissipation; for insulation fault alarms, detect the insulation resistance of the inverter DC side and repair insulation damage.
III. Cable Faults: Concealed Faults Prone to Safety Accidents
The cables of PV power stations are responsible for electrical energy transmission, including DC cables, AC cables, and control cables. Their faults are characterized by strong concealment and high troubleshooting difficulty. Common problems are short circuits, open circuits, poor contact, and aging damage.
Sectional inspection: Disconnect the cable system in sections, and use an insulation resistance meter to detect the insulation resistance of each section of cable (the insulation resistance of DC side positive and negative poles to ground > 2 MΩ, AC side feeder circuit > 0.5 MΩ, secondary circuit > 1 MΩ) to determine the short circuit/leakage section.
Appearance inspection: Check whether the cable sheath is damaged or waterlogged, whether the cable joints are oxidized or short-circuited, and whether the buried cables are corroded or crushed.
Disposal of damaged cables: Replace the damaged cable section, adopt waterproof and fireproof sealing treatment at the joint, and wrap the DC cable joint with insulating tape.
Short circuit repair: Clean the oxide layer and short-circuit substances at the cable joint, re-tighten the wiring; if the cable is short-circuited internally, directly replace the entire section of cable.
Leakage disposal: Detect the cable grounding situation, repair the poorly grounded parts, and replace the invalid leakage protector and SPDs.
(II) Common Fault 2: Cable Open Circuit and Poor Contact
Fault Performance: No current input to some modules or inverters, partial power failure of the power station, and no current transmission in a certain section of cable shown by current detection.
Troubleshooting Steps:
Current detection: Use a clamp meter to detect the cable current section by section. If there is no current in a certain section of cable, it is determined to be an open circuit or poor contact.
Joint and terminal inspection: Check whether the cable terminals and joints are loose or ablated, and whether the control cable terminals are detached.
Solutions:
Poor contact: Re-tighten the cable terminals and joints, replace the ablated terminals and joints, and ensure firm and good contact of the wiring.
Open circuit disposal: If the cable is open-circuited internally, the cable needs to be replaced; if the joint is open-circuited, re-wire and do a good job in sealing protection.
Appearance inspection: For outdoor cables, check whether the sheath has cracks and aging; check whether there is water accumulation and corrosion in the cable well; check whether there are heavy objects crushing and corrosive substances around the buried cables.
Insulation detection: Regularly detect the cable insulation resistance. If the insulation resistance continues to decrease, it indicates that the cable is seriously aged.
Aged cables: Timely replace aged and damaged cables. Choose models with good weather resistance for outdoor cables, and do a good job in anti-corrosion and protection treatment for buried cables.
Environmental damage repair: Clean the water in the cable well, repair the damaged cable sheath, and set up guardrails around the cables to avoid heavy object crushing and corrosion.
IV. Key Points for Fault Prevention and Daily Maintenance
Regular inspection: Conduct a comprehensive inspection of modules, inverters, and cables once a month, focusing on checking the appearance, wiring, heat dissipation, and sealing conditions to find potential problems in time.
Cleaning and maintenance: Avoid cleaning modules during high-temperature periods, and clean the dust inside the inverter and power distribution cabinet every six months to keep the equipment with good heat dissipation and stable insulation performance.
Data monitoring: Real-time monitor data such as module current, inverter power, and cable insulation resistance through the PV monitoring system, and give early warning for abnormal data.
Professional maintenance: Invite a professional operation and maintenance team to conduct a comprehensive inspection of the power station once a year, troubleshoot concealed faults, and replace aged components to ensure the long-term stable operation of the power station.
The core of PV power station fault troubleshooting lies in "accurate positioning and quick disposal". For common problems of the three core components (modules, inverters, and cables), mastering the troubleshooting logic and solutions can not only reduce the fault shutdown time and improve power generation efficiency but also reduce operation and maintenance costs, making photovoltaic power generation truly stable, safe, and efficient.
