Problem 1: Hot spots appear on components

The main causes of hot spots are: component quality problems (excessive internal resistance), cracks and partial surface shadows. Hot spots can seriously damage photovoltaic solar modules or systems, and even cause fire accidents, but it is difficult to find them by visual inspection alone, so it is best to use an infrared thermal imager to check.

Problem 2: Not meeting the expected power generation

Solar resources are measured in peak sunshine hours, which are the hours per day that can produce 1,000 watts per square meter of solar modules. Peak sunshine hours can be changed by many factors, especially time, season and weather conditions. Therefore, the installation position and angle of solar modules play a crucial role in generating electricity. After the system is installed, it is ensured that its performance meets the design requirements by measuring its electrical parameters and the actual power output of the components. Using the combination of a solar irradiance meter and a multi-function tester, calculate the IV curve of the power output. Even when installed correctly, PV systems may not produce the expected power output. In order for the PV system to achieve the expected output, it is important to ensure that the system can receive the correct amount of irradiance energy. It is necessary to use a solar irradiance meter to test the irradiance of the current module position and adjust the angle repeatedly until the irradiance is found. maximum position.

Problem 3: Electrical faults in PV system

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

1. Photovoltaic panel failure:

Before inspection, it is necessary to record the input voltage and current level of the inverter, and the following problems may be encountered:

The entire PV system is off/not generating electricity - there may be a problem with the inverter;

PV system output is lower than expected - possibly a component or module issue.

It is recommended to start the inspection along the line from the combiner box. Using a current clamp meter will greatly improve the inspection efficiency.

2. Photovoltaic load failure:

(1).Check that the correct voltage is present at the load connections. If the voltage is too low, it may be necessary to reduce the load on the circuit or use a larger wire.

(2). Check fuses and circuit breakers and replace faulty fuses/circuit breakers if there is a problem.

(3).If the load is a motor, the internal thermal breaker may trip, or the windings in the motor may be open. Need to replace another load and see if it works.

3. Photovoltaic ground fault:

DC ground faults are a common type of fault in PV systems and are usually caused by poor current flow through the equipment ground conductor due to damaged ground conductor insulation, improper installation, pinched conductors, and water ingress. DC ground faults are especially dangerous in large PV systems because they are not easily detected and can be extremely harmful. Ground fault protection (GFP) devices cannot detect small current leakage (< 1A) in a ground fault, so this is called a "blind spot". Once a malfunction occurs, it will not only cause safety problems, but also create a fire hazard.

Troubleshooting steps:

1) Use a multimeter for 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) Identify the source of the ground fault

①Remove the positive and negative wires to ensure that the inverter is isolated from the array;

②Close the DC disconnecting device and apply voltage to the wire;

③Measure the voltage between the positive and negative conductors to determine the open circuit voltage of the component;

④Use a ground resistance tester to measure the positive grounding and negative grounding 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, replace the wire immediately and keep a record of the test and replacement.

4. Photovoltaic inverter failure:

If the solar inverter is not producing the correct output, check the output voltage, current and power of the inverter with an AC clamp meter and compare it with the values recorded during the last inspection. Because the load on the inverter may require too much current, reduce the load or install a larger converter.

If the problem persists, continue to check for possible faults with the clamp meter:

• blown fuse

• circuit breaker tripped

• disconnection

In the event of a power failure, all ground faults need to be checked and repaired before starting the drive again.

Also, any voltage problems with the power company can cause the inverter to shut down.