4. 1 PV Module Design, Manufacture, Performance and Reliability
Summary / Abstract:
Potential Induced Degradation (PID) continues to be a relevant topic for operators and owners of PV plants. For more than 10 years of intensive research and experience in the scientific and consultant communities, thephenomenais welldescribedand the countermeasures are available, however new developments in solar PV module technologies have provided new challenges that need to be addressed. Testing laboratories including PI Berlin have tested many of these new module types over the last two years, primarily with PERC cells. The results have shown that some modules types had a degradation of between 1 to 3 % under PID-stress testing. The urgent topic is that degradations under (+) system voltage direction are higher than under (-).This may bebelow the common industry threshold of 5 %, but could still account for significant losses in capacity for PV plants. What makes the evaluation even more difficult is the fact that PERC cells can also be LeTID sensitive and thus have superimposed temporary power losses.The publication will present PI Berlin’s latest PID and LeTID test results on current module technologies. The results contain a comparison between PID positive and negative test bias direction. The tests were performed at PI Berlin’s accredited test laboratories in Berlin, Germany and Suzhou, Chinaand containat least 45 different module types and more than 200 individualmodules. The PID-stress tests followed the IEC TS 62804-1 standard under 85°C, 85 % r.H. and 96h at system voltage (insome cases 48 hours only). LeTID was performed accordingto the current draft standard. The main objective of this presentation is to initiate a discussion about these new developments in PID sensitivity and to compare the results to those from LeTID tests.