Proposed generalized models for estimating the reliability of a stand-alone solar photovoltaic power system

Abstract

New mathematical models for the reliability of a stand-alone solar photovoltaic power system (SPV) are proposed in this paper. One of the important reliability indices is the loss-of-load probability (LOLP), so its dependence on the design parameters is modelled. The special role that the battery storage can play to fulfil the desired reliability level (RL) is clearly demonstrated. For a given size of solar cells array (SCA), an econometric model of LOLP is developed to yield the incremental change in the system's total lifetime costs on modifying the LOLP level. The effect of the failure rate of each system component on the SPV reliability level has been estimated and is fully discussed. The behaviour of the SPV reliability level with SCA tilt angle and series-parallel configuration is established under the prevailing working conditions. The significance of the relationship between the preventive maintenance schedule for each of the system components and its reliability is analysed, resulting in a new chart that enables schedules which yield the required system reliability to be planned directly.