With growing environmental concerns over the climate change risks associated with power generation using fossil fuels, solar power generation has emerged as one of the most rapidly growing renewable sources of electricity in the world. In recent technological advancements for improving the performance of PV system, efficiency improvement of solar PV cell and power converter stage has become a critical area of interest for researchers. Sensitivity and reliability studies of a system are important tools to evaluate the performance of the system. In this paper, sensitivity and reliability models of a grid-connected PV system are developed. Analytical relations of first order sensitivity are developed for PV cell and DC-DC converter. Further, reliability models are developed for individual components and for different configurations of PV system using Pareto analysis and logic gate representations. The main reference for electronic component reliability evaluation is MIL-HDBK-217 military handbook and MTBF calculator software by ALD. The developed models can be applied to any PV system to have a better insight.