The operational lifetime of large solar PV arrays is investigated using the probability theory for the assessment of reliability. Arrays based on the following three solar cell interconnection schemes have been considered: (i) simple series-parallel (SP) array, 00 the total-crossed-tied (TCT) array which is obtained from the SP array by connecting ties across each row of junctions and (iii) the bridge-linked (BL) array in which all cells are interconnected in bridge rectifier fashion. To evaluate the reliability of the bridge-linked configuration, the cut-set technique is used. Computational results based on arrays consisting of (720 x 20) solar cells indicate that the operational life of an array is almost doubled by the introduction of cross ties (TCT or BL schemes) in the array. The operational lifetime can be further increased by similar to30% by modularized networks based on TCT and BL configurations. These results are based on a theoretical analysis, however, and not on measured efficiency and life expectancy of solar cells. (C) 2002 Elsevier Science Ltd. All rights reserved.