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Problem 1 Components have hot spots
The main causes of hot spots are: component quality problems (excessive internal resistance), cracks and partial surface shadows.
Hot spots can seriously damage photovoltaic modules or systems, and cause fire accidents in severe cases, but it is difficult to detect them only by visual inspection, so it is best to use an infrared thermal imaging camera for inspection.
Problem 2 Failure to reach the expected power generation
Solar resource is measured in peak sunshine hours, which is the number of hours per day that can achieve 1,000 watts per square meter of solar module output.

Peak sunshine hours vary by many factors, not least time of day, season and weather conditions. Therefore, the installation position and angle of solar modules play a vital role in the power generation.

After the system is installed, ensure that its performance meets the design requirements by measuring its electrical parameters and the actual power output of the components. Use the combination of solar irradiance meter and multi-function tester to calculate the IV curve of power output.
Even when installed correctly, a photovoltaic system may not generate as much electricity as expected. In order for a photovoltaic system to achieve the desired output, it is important to ensure that the system is receiving the correct amount of irradiance energy. It is necessary to use a solar irradiance meter to test the irradiance at the current module location and repeatedly adjust the angle until the irradiance is found maximum location.
Problem 3 Electrical Faults in Photovoltaic Systems

The most common photovoltaic system problems are usually related to panels, loads, grounding and inverters.

l Photovoltaic panel failure:
Before checking, you need to record the input voltage and current level of the inverter, you may encounter the following problems:
Entire PV system shuts down/does not generate power - possibly a problem with the inverter;
The output of the PV system is lower than expected - possibly a component or module problem.

It is recommended to check along the line starting from the combiner box. Using a current clamp meter will greatly improve the efficiency of checking. Possible failure types are:
Dirt, wiring problems and loose connections (especially union nuts between components);
l There are shadows or dust on the components (easy to cause output reduction)

l Photovoltaic load failure:
1. Check that the correct voltage is present at the load connections. If the voltage is too low, you may need to reduce the load on the circuit or use larger wires.
2. Check fuses and circuit breakers, replace faulty fuses/circuit breakers if defective.
3. If the load is a motor, the internal thermal circuit breaker may have tripped, or a winding in the motor may have opened. Need to replace another load and see if it works.

l Photovoltaic ground fault:
DC ground faults are a common type of fault in photovoltaic systems and are usually caused by poor current flow through the equipment ground wire due to damaged ground wire insulation, improper installation, wire pinching, and water ingress.

DC ground faults are particularly dangerous in large PV systems because they are not easy to detect and can be extremely harmful. Ground fault protection (GFP) devices cannot detect small current leakages (< 1A) in ground faults, so this is called a "blind spot". Once a failure occurs, it will not only cause safety problems, but also create a fire hazard.


Troubleshooting steps:
1. Use a multimeter to conduct a continuity test to check whether the fuse of the circuit breaker is blown;
2. Use an insulation resistance tester to check the insulation performance of the wire;
3. Determine the source of the ground fault
1) Remove the positive and negative wires to ensure that the inverter is isolated from the array;
2) Close the DC disconnect device and apply voltage to the wire;
3) Measure the voltage between the positive and negative wires to determine the open circuit voltage of the component;
4) Use a ground resistance tester to measure the positive and negative grounds respectively.

If there is no ground fault, the voltage measured from either conductor to ground should be 0V.
If ground voltage is present on either wire, check each connection point (DC disconnect, combiner box) all the way back to the assembly. Once a fault is found, the wire should be replaced immediately, and the test and replacement records should be kept.

l PV inverter failure:
If the inverter is not producing the correct output, check the output voltage, current and power of the inverter with an AC clamp meter and compare them with the values recorded during the previous inspection. Because the load on the inverter may require too much current, the load can be reduced or a larger converter installed.

If the problem persists, continue to use the clamp meter to continue checking for possible faults:
• Fuse blown
• Tripped circuit breaker
• Disconnection
In the event of a power outage, all ground faults need to be checked and repaired before starting the frequency converter again.

Plus, any voltage issues with the power company could cause the inverter to shut down.