Abstract
The degradation in performance for eight photovoltaic (PV) modules stressed at high voltage (HV) is presented. Four types of modules--tandem-junction and triple-junction amorphous thin-film silicon, plus crystalline and polycrystalline silicon modules--were tested, with a pair of each biased at opposite polarities. They were deployed outdoors between 2001 and 2009 with their respective HV leakagecurrents through the module encapsulation continuously monitored with a data acquisition system, along with air temperature and relative humidity. For the first 5 years, all modules were biased continuously at fixed 600 VDC, day and night. In the last 2 years, the modules were step-bias stressed cyclically up and down in voltage between 10 and 600 VDC, in steps of tens to hundreds of volts. Thisallowed characterization of leakage current versus voltage under a large range of temperature and moisture conditions, facilitating determination of leakage paths. An analysis of the degradation is presented, along with integrated leakage charge. In HV operation: the bulk silicon modules degraded either insignificantly or at rates of 0.1%/yr higher than modules not biased at HV; for thethin-film silicon modules, the added loss rates are insignificant for one type, or 0.2%/yr-0.6%/yr larger for the other type.
Original language | American English |
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Number of pages | 14 |
State | Published - 2010 |
Event | SPIE 2010 Optics and Photonics Conference - San Diego, California Duration: 1 Aug 2010 → 5 Aug 2010 |
Conference
Conference | SPIE 2010 Optics and Photonics Conference |
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City | San Diego, California |
Period | 1/08/10 → 5/08/10 |
NREL Publication Number
- NREL/CP-520-47463
Keywords
- degradation
- high-voltage stress
- leakage currents
- photovoltaic
- reliability