Question 1

What is potential induced degradation (PID) in solar panels?

Accepted Answer

Potential induced degradation (PID) is a performance loss phenomenon in solar panels caused by high voltage stress between the solar cells and the module frame. It occurs when stray currents flow through the module materials, causing ion migration that degrades the cell's anti-reflective coating and reduces power output. PID is most common in systems with high string voltages, especially those using transformerless inverters with negative grounding.

Question 2

What factors increase the risk of PID in solar PV systems?

Accepted Answer

The main factors that increase PID risk include: high system voltage (above 600V), elevated operating temperatures above 50°C, high humidity environments above 80% RH, negative ground fault protection configurations, transformerless inverters, module position at the negative end of the string, and extended exposure time under voltage stress. Panels with silicon nitride anti-reflective coatings are more susceptible than those with aluminum oxide coatings.

Question 3

How can I prevent or mitigate PID damage in my solar system?

Accepted Answer

PID prevention and mitigation strategies include: using PID-resistant modules certified to IEC 62804, installing PID boxes or reverse-bias recovery devices, ensuring proper system grounding, using transformerless inverters with built-in PID prevention, limiting string voltage below 600V where possible, applying anti-PID coatings, performing periodic reverse-bias recovery at night, and monitoring system performance regularly for early signs of degradation.

PID Risk Checker

System Parameters

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Risk Factor Breakdown

Mitigation Recommendations

Frequently Asked Questions

What is potential induced degradation (PID) in solar panels?