Reliability and maintenance in high-power grid-connected photovoltaic systems: a survey of critical issues and failures

In the last ten years, after the first Italian feed-in-tariff, it has been observed that during the operation and maintenance of large-scale grid-connected photovoltaic systems, several unexpected problems may occur whose solution calls for specific strategies not initially planned at the design stage. Based on information gathered from more than 80 plants located in Italy, this work outlines the most widespread issues, the principal typologies of failures and unexpected events that occur in photovoltaic plants and tries to propose the best ways to solve them.