Complete Guide to Solar PV System Troubleshooting and Solutions

 

Solar photovoltaic (PV) system is a green energy system that converts solar energy directly into electricity. The core principle of PV systems is based on the photovoltaic effect, in which photon energy is converted into electrical energy by photovoltaic cells and converted into usable alternating current (AC) electricity by an inverter.

How photovoltaic systems work

The core technology of photovoltaic systems is the photoelectric effect, a physical phenomenon that releases electrons by absorbing photons. The photovoltaic cell, usually made of a semiconductor material such as silicon, is the basic unit of a photovoltaic system. Photons interact with electrons in the semiconductor material, causing the electrons to jump to a higher energy level, thus generating an electric current. Photovoltaic cells convert the photon energy from sunlight into direct current (DC), which is then converted into alternating current (AC) by an inverter for use in homes or industrial equipment.

A photovoltaic system is more than just a simple electrical energy conversion device; it includes other important components such as inverters, battery storage systems, racks and cables. The inverter is one of the key components of a PV system. It is not only responsible for converting DC power to AC power, but also monitors the system's operating status to ensure the stability of the power output. The battery storage system, on the other hand, is used to store excess power for use at night or when there is insufficient light, thus increasing the system's self-sufficiency.

 

 

Main components of a photovoltaic system

Photovoltaic Module: A photovoltaic module is a component made up of multiple photovoltaic cells connected in series or parallel and is responsible for converting solar energy into electricity. The efficiency and quality of the PV module directly affects the power generation capacity of the entire system. Different types of PV modules, such as monocrystalline silicon, polycrystalline silicon, thin film, etc., have different performance and application scenarios.

Inverter: The inverter is one of the core devices in the PV system, and its function is to convert the DC power generated by the PV module into AC power that can be used by the grid. In addition, the inverter also has the function of monitoring, protecting and managing the whole PV system, which can detect and respond to faults in the system in time.

Battery storage system: In order to better utilize the power generated by the PV system, especially during periods of low light or high electricity prices, battery storage systems can store excess power. Common energy storage devices include lead-acid batteries, lithium batteries, etc. Their capacity and performance determine the stability and continuity of the power supply of the PV system.

RACKING SYSTEM: Racking is used to secure the PV module and ensure that it receives sunlight at the optimal angle. The bracket system needs to be able to withstand natural conditions such as wind and snow, so its material and design are very important. The angle and orientation of the bracket directly affects the power generation efficiency of the PV system.

Cables and junction boxes: Cables are responsible for transmitting the current generated by the PV modules to the inverter and the battery storage system. The junction box, on the other hand, is used to protect the connection points of the cables from environmental influences that may cause short circuits or other electrical failures. The quality of the cables and the rationality of the wiring are important factors in ensuring the safe operation of the system.

 

 

Common PV System Fault Types

Despite being a relatively stable and mature technology, solar PV systems may still experience various types of faults during their long-term operation. These failures will not only affect the system's power generation efficiency, but may also cause safety hazards. Therefore, understanding and mastering the common types of faults in PV systems is crucial for timely troubleshooting and restoring the system to normal operation. The following will introduce several common types of PV system failures in detail.

Battery Storage System Failures

The battery storage system plays a key role in balancing the power supply in a PV system, but it can also experience some common failures:

Overcharging or overdischarging: When a battery is overcharged or overdischarged, it can lead to abnormal internal chemical reactions that can affect battery life or even lead to battery damage. Modern energy storage systems are often equipped with a battery management system (BMS), but these problems can still occur if the BMS fails or is not set up properly.

Capacity Decay: The energy storage capacity of a battery will gradually decay as the usage time increases. The rate of capacity decay depends on factors such as the type of battery, the environment in which it is used, and the frequency of charging and discharging. Excessive capacity degradation can significantly reduce the stability and economy of a PV system.

Temperature Abnormalities: The operating temperature of a battery has a significant impact on its performance and life. If the battery temperature is too high or too low, it may lead to accelerated aging of internal materials and even cause safety accidents.

Battery String Failure: In a series-connected battery pack, if a certain battery fails, it may cause the performance of the whole battery pack to decline. Common battery string failures include increased internal resistance of individual cells, liquid leakage, etc.

Cable and Connector Failures

The cables and connectors in a PV system are responsible for transmitting electrical energy from the PV module to the inverter, battery storage system, and the grid. Since these components are exposed outdoors, common types of failures include:

Cable deterioration: prolonged exposure to UV rays, temperature changes and humidity can cause the insulation of cables to deteriorate and crack, which in turn can lead to leakage or short circuits.

Poor contact: A poor contact between the cable and the connector may trigger increased resistance, heating, or even arcing, leading to a fire or system shutdown.

Cable overload: If the specification of the cable does not meet the design requirements of the system, especially when a large current passes through, it may lead to overheating of the cable, melting of the insulation layer, and ultimately lead to a serious malfunction.

Rat or mechanical damage: Cables may be subject to external damage, such as rodent gnawing or mechanical construction damage, which can result in short-circuiting or disconnection of the cable.

 

 

Impact of environmental factors

The operation of a photovoltaic system not only depends on the stability of the internal components, but is also affected by external environmental factors:

Temperature variations: Extreme temperature variations can affect the performance of PV modules and cells. At high temperatures, the efficiency of the PV module decreases, while low temperatures may affect the energy storage capacity of the battery.

HUMIDITY AND CORROSION: When exposed to high humidity for long periods of time, the metal parts of PV systems are prone to corrosion, leading to poor contact or short circuits. In addition, salt spray environments pose a particular challenge for PV systems in coastal areas.

Dust and dirt accumulation: Dust and dirt accumulation on the surface of a PV module can significantly reduce light transmission, thereby reducing power generation. Dust accumulation is particularly problematic in dry, windy environments.

System monitoring failures

PV systems are often equipped with a monitoring system that monitors the operating status of individual modules in real time. However, the monitoring system itself can fail:

Communication Failure: The monitoring system transmits data to the backend system through the communication network. If the communication network fails or the equipment is set up incorrectly, it may lead to data transmission failure and prevent timely monitoring of the system's operation status.

Data Acquisition Abnormalities: Due to sensor failures or incorrect acquisition equipment settings, the monitoring system may not be able to accurately acquire the operating data of the PV system, resulting in data distortion or system false alarms.

Crash of monitoring platform: A crash or serious failure of the software system of the monitoring platform may cause the system to be unable to display or analyze data normally, affecting the management of the PV system.

 

 

Common reasons for PV system power generation reduction

Photovoltaic module surface contamination

Cause: Dust, dirt, bird droppings and other contaminants on the surface of PV modules can block sunlight and reduce the light intensity of PV modules, thus reducing power generation.

Solution: Clean the surface of the PV module regularly. Use a soft cloth or special cleaning tools, avoid using corrosive cleaning agents. Cleaning should be selected at times of lower light intensity to minimize the impact on system operation.

Photovoltaic module aging

Reason: As the use of photovoltaic modules grows, their internal materials will gradually age, resulting in a decrease in conversion efficiency. The performance of PV modules usually declines after long-term use.

Solution: Regularly test the performance of PV modules and replace badly aged PV modules if necessary. Select high-quality, durable PV modules and ensure that they are installed in a suitable environment to extend their service life.

Inverter failure

Cause: Inverter failure can result in the DC power generated by the PV module not being effectively converted to AC power, thus affecting the amount of power generated. Inverter failure may manifest itself in the form of the device failing to start, decreased efficiency, or error codes.

Solution: Regularly check the operating status and performance of the inverter to ensure that it is working properly. When a fault occurs, contact a professional for overhaul or replacement in a timely manner.

Battery energy storage system failure

Cause: Failure of the battery storage system may result in a reduction in the ability to store electrical energy, affecting the overall power generation effect of the system. For example, inadequate charging or abnormal discharging of batteries can reduce the available electrical energy.

Solution: Regularly check the health status of the battery, including charging and discharging performance. Use high-quality batteries and ensure that the battery storage system is properly maintained and managed.

Problems with cables and junction box

Cause: Aging or broken cables or damaged junction boxes may result in poor power transmission, which may affect the amount of power generated by the PV system. Loose cable connections or broken insulation are also common problems.

Solution: Regularly check the condition of cables and junction boxes to ensure that connections are secure and undamaged. Repair or replace faulty cables and junction boxes in a timely manner.

Problems with the bracket system

Cause: Loose, damaged or improperly installed racking systems may affect the angle and fixation of PV modules, which in turn reduces power generation efficiency. The design and installation of the racking needs to be in accordance with the specifications to ensure the optimal angle of the PV module.

Solution: Regularly check the mounting and fixing status of the racking. Ensure that the racking is firm and adjust the angle of the PV module according to the design requirements to optimize power generation.

Environmental factors

Reason: Environmental factors such as haze, fog, rain, snow and other weather conditions can affect light intensity and thus reduce the power generation of the PV system. These factors are not controllable, but the impact can be reduced by optimizing the system design.

Solution: Select PV system components that are suitable for local climate conditions, such as waterproof and dustproof designs. The design and installation of the system should take into account possible environmental factors to minimize the impact of the environment on power generation.

Inadequate system design

Reason: Improper system design may lead to problems such as irrational arrangement of PV modules and mismatched inverter configurations, thus affecting the overall power generation. For example, unsuitable tilt angle of PV modules or shadow shading.

Solution: When designing and installing the PV system, fully consider factors such as light angle and shadow shading. Ensure that the system design is reasonable and the selection of modules meets the actual demand to achieve the best power generation effect.

 

 

Detection and analysis of reduced power generation

Use of monitoring system

Methods: Modern PV systems are usually equipped with monitoring systems that can track power generation and system operation status in real time. Through the monitoring system, the cause of the decrease in power generation can be detected in time.

Steps: Check the data records and alarm messages of the monitoring system to analyze trends in power generation and locate possible problem areas.

Periodic Maintenance Check

Methods: Conduct regular comprehensive inspections of the PV system, including components such as PV modules, inverters, battery storage systems, cables and racking.

Steps: Arranging for professional staff to carry out inspections and maintenance, checking the working condition of the components and ensuring the normal operation of the system.

Data Analysis

Methods: Analyze historical power generation data, compare the difference between power generation under normal conditions and current power generation, and find out the reasons for the decrease in power generation.

Steps: Using data analysis tools, perform an in-depth analysis of the generation data to identify possible causes of failure or design flaws.

 

 

Solution Implementation Steps

Problem Diagnosis: Perform detailed troubleshooting based on the cause of reduced power generation. Inspect components such as PV modules, inverters, battery storage systems, cables, junction boxes and racking.

Fault Repair: Based on the diagnosis results, repair or replace the components with problems. Make necessary adjustments and optimizations to restore the system to normal operation.

Performance Optimization: After resolving the fault, optimize the performance of the PV system, including adjusting the angle of the PV modules, updating software settings, etc., to improve the system's power generation efficiency.

Preventive Measures: Develop a system maintenance plan and regularly inspect and maintain the PV system to prevent recurrence of similar failures. Improve the stability and reliability of the system.

 

 

Finally

The main purpose of a photovoltaic system is to convert sunlight into electricity to provide users with a stable power supply. However, during actual use, the power generation of PV systems may be reduced. This situation not only affects the efficiency of the system, but may also lead to economic losses. Understanding the causes of reduced power generation and their solutions is essential to keep the system running efficiently.