Reliability; Probability of success; Derating; Redundancy
In this study, a reliability estimation method was used to predict the probability of success of
various components of photovoltaic (PV) systems. Various methods of reliability improvement, to
improve the probability of success of the PV system for the least annualised cost, are discussed. This paper mathematically estimates and analyses the reliability estimation of the battery voltage regulators (BVRs) that are generally used in PV systems. Therefore, this can be of vital help to a PV system designer for
improving the reliability of the BVRs. The paper also describes different reliability engineering techniques for improving the probability of success of PV system components. In the case study, those BVRs whose probability of success is 18% in the laboratory condition, were actually found to have less than 1% probability of success if subjected to tropical field conditions for the expected life period of 10 yr. For the same BVR, the probability of success increases to 99% for the same period if proper reliability-related design considerations are incorporated.