Testing PV Central Inverters' Compliance with International Grid Codes

Abstract

In many electrical grids worldwide, the rising amount of installed PV power entails a considerable influence of PV systems on grid quality and stability. Consequently, in the wake of the revised German medium voltage directives issued in 2009, new requirements for PV inverters have been established internationally. At Fraunhofer ISE’s Inverter Laboratory, more than 25 large PV inverters with a nominal power of up to 880 kVA have been characterised in the past three years. In this period, the focus of many inverter manufacturers has begun to shift from traditional European markets towards a truly international perspective. Therefore, experiences with numerous different grid codes have been gained by our team. This work summarises the similarities and differences between these grid codes. Additionally, several requirements that have proved to be critical will be examined in detail. In conclusion, the adequacy of these grid codes to guarantee the safe and reliable operation of electrical grids is discussed.