Test and Analysis of Potential Induced Degradation in Crystalline Silicon PV Modules

Potential induced degradation (PID) has become one of the main factors that reduce the output power of PV module. Modules are easy to be affected by PID if the PV system operates under a humid environment. PV modules in a mountain PV power station under warm temperate climate in China were tested to study the occurrence regularity of PID and its effect on the electrical performance of PV strings. The test items include power degradation test, Electroluminescent (EL) test, Infrared Radiation (IR) test and series connection mismatch loss test of PV module. The power recovery method for PV modules affected by PID was also researched in this paper. Test results shows that the power of PV modules affected by PID can decrease seriously. In the environmental chamber with high temperature and humidity condition, power loss of PV modules affected by PID can recovery with a positive bias voltage stress.