The PID effect occurs when the difference in electrical potential between the materials used in photovoltaic panels, such as glass and frames, and the ground causes unwanted ion migration. This phenomenon leads to degradation of the semiconductor material, resulting in a loss of panel performance. This effect can occur in any type of module, regardless of its manufacturing technology, and the consequences can be severe.

The PID effect is caused by several factors:

1. High operating voltages: Panels operating at voltages above 1000 V are more susceptible to the PID effect.
2. Humidity: High humidity promotes ion migration, increasing the risk of degradation.
3. Temperature: Higher temperatures accelerate the processes leading to the PID effect.
4. Quality of materials: The use of low-quality materials in the manufacture of panels increases susceptibility to the PID effect.

The PID effect directly affects the performance and efficiency of photovoltaic panels. It causes negative effects such as:

1. Decrease in power output: Decreases the efficiency of the module and, consequently, of the entire photovoltaic system.
2. Reduction in conversion efficiency: The PID effect leads to a reduction in the efficiency of the conversion of sunlight into electricity.
3. Permanent damage: In extreme cases, permanent damage to the photovoltaic module can occur, resulting in significant property damage.

To minimise the risk of a PID effect, various methods are used to avoid or minimise the occurrence of this adverse effect:

1. Use of PID-resistant materials: Manufacturers can choose materials that are less susceptible to the PID effect, which increases the durability of the panels.
2. Accurate earthing of module frames and structures: Correct grounding of the PV system can reduce the risk of PID effects.
3. Use of PID-recovery devices: Some of the high-power inverter models with a system voltage of 1500 Vdc, such as the Sungrow SG350HX ( Falownik Szeregowy SG350HX)) , have a function to neutralise the adverse effects of the PID effect by applying a small reverse voltage at night.

Research on the PID effect focuses on understanding the mechanisms of this phenomenon and developing effective methods to prevent it. Many modern photovoltaic panels are already designed to minimise the risk of the PID effect, contributing to the long-term stability and performance of solar systems. Among the manufacturers that have modules with resistance to the PID effect in their portfolio is Trina Solar with the model TSM-NEG21C.20 (Photovoltaic panel Trina Vertex N NEG21C.20 695-720), which is popular for large-scale applications due to its high unit power.

The PID effect is a significant challenge in the photovoltaic industry, but by understanding its causes and effects and using appropriate prevention methods, its impact can be significantly reduced. The use of PID-resistant materials, correct earthing, the use of PID-recovery devices and regular monitoring and maintenance of photovoltaic systems are key measures that can ensure the longevity and efficiency of solar installations.