PV-grid performance under dynamic weather conditions

This paper presents results from research in the stability of DC/AC power generated by PV (photo voltaic) systems. It is well known that the generated power can change abruptly due to especially moving clouds, causing potential instability of the DC/AC power grid. The transient behavior of moving clouds is analyzed in detail via long term (several years) high speed recording of panel/inverter performance, as well as high speed recording of IV-curves of selected panels performed under Scandinavian as well as Italian weather conditions. The performance of string inverters and central inverters are analyzed and compared. The result of > 10 mill. recordings are presented by graphical and statistical means and show an extremely low occurrence of Standard Test Condition (STC) conditions).