Author:

Keywords:

Science & Technology, Technology, Physical Sciences, Energy & Fuels, Materials Science, Multidisciplinary, Physics, Applied, Materials Science, Physics, certification, grid connection, inverters, islanding, protection, safety, standardization, testing, RESIDENTIAL PHOTOVOLTAIC SYSTEMS, 0204 Condensed Matter Physics, 0906 Electrical and Electronic Engineering, 0912 Materials Engineering, Applied Physics, 4008 Electrical engineering, 4009 Electronics, sensors and digital hardware, 4016 Materials engineering

Abstract:

Islanding is still one of the major controversial subjects in the international harmonization of grid connection requirements for distributed generation, and particularly photovoltaics. As long as islanding is not intended in order to back up a loss of mains, it should be avoided. The present study reviews the theory of unintentional islanding and assesses the probability of occurrence of the phenomenon, based on previous studies and theoretical considerations. While islanding is virtually impossible if only a small number of distributed generation units is connected to a distribution grid, with higher distributed generation densities, the possibility of islanding becomes realistic. The risk associated with unintentional islanding is estimated, and adequate requirements for functional safety of protection devices are determined in order to ensure the necessary additional degree of safety to be introduced by an islanding prevention device. Finally, a fundamental set of requirements with regard to islanding, to be included in an international grid connection guideline, is derived from the study. Copyright © 2003 John Wiley & Sons, Ltd.