Network Structural Equation Modeling for Photovoltaic Modules Lifetime Performance in Real-World and Accelerated Exposures

• Activity Number: 126 - New Development in Reliability Models and Innovative Applications
• Type: Contributed
• Date/Time: Monday, July 30, 2018 : 8:30 AM to 10:20 AM
• Sponsor: Section on Physical and Engineering Sciences
• Author(s): Wei-Heng Huang* and JiQi Liu and Alan J. Curran and Justin S. Fada and Jennifer L. Braid and Roger H. French
• Companies: Case Western Reserve University and Case Western Reserve University and Case Western Reserve University and Case Western Reserve University and Case Western Reserve University and Case Western Reserve University
• Keywords: Degradation; PV module; Structural Equation Modeling; Cross-correlation

Abstract

In the study of photovoltaic (PV) modules degradation, a statistical approach is necessary for lifetime prediction. Structural Equation Modeling (SEM) allows for exploratory modeling, resulting in a system of equations describing the univariate relationships between variables. However, SEM typically only fits a system of linear equations, while network SEM (netSEM) enables nonlinear relationships among variables. Applied to indoor accelerated and outdoor exposure tests of PV modules, netSEM also allows for cross-correlation of indoor and outdoor degradation models. The cross-correlation scale factor (CCSF), determined by ordinary least squares, re-normalizes the independent indoor exposure time variable to best cross-correlate with the outdoor (real-time) model. We evaluate the performance of different indoor/outdoor model combinations to determine the indoor accelerated test which most closely relates to real world performance. NetSEM/cross-correlation represents a new direction in reliability research.