Proportional Hazards Modeling of Environmental Impacts on Reliability of Photovoltaic Modules
E. Suresh Kumar1, Bijan Sarkar2
1E. Suresh Kumar, Department of  Production Engineering, Jadavpur University, Kolkata, India.
2Dr. Bijan Sarkar, Department of  Production Engineering, Jadavpur University, Kolkata,  India.
Manuscript received on November 22, 2012. | Revised Manuscript received on December 13, 2012. | Manuscript published on December 30, 2012. | PP: 110-115 | Volume-2, Issue-2, December 2012.  | Retrieval Number: B0861112212 /2012©BEIESP

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Abstract: The effect of operational environment on the reliability performance of solar photovoltaic module can be analysed. The first step is to identify which factors have the most significant influence on the reliability performance of photovoltaic modules and systems and how large is the effect. The available information about the operating conditions of the PV modules can be uniformly formulated based on two alternatives , good/desired (+1) and bad/undesired (-1) conditions. With respect to reliability, the available method PHM (Proportional Hazards Model) can be used for predicting the effect of environment on the system reliability. The reliability characteristics of PV modules can be influenced by environmental conditions such as temperature, snow, wind etc and these influences therefore need to be seriously considered in the prediction of reliability in the design phase. The conventional reliability equation deals with over a time interval and is a measure of the probability for failure-free operation during the given interval, i.e., it is a measure of success for a failure free operation. It is often expressed as R(t) = exp(-t/MTBF) = exp(-λt), where MTBF is the Mean Time Between Failure and λ is the failure rate, which is the reciprocal of MTBF. In this paper an attempt is made to modify the time equation of reliability with incorporating environmental impacts like temperature, wind and snow.
Keywords: Mean Time Between Failures, Failure rate, Weibull distribution, Proportional Hazards Model, Time to failure (TTF) time between failures (TBF).