A development of compact and reliable protective control unit for grid connected small residential PV systems

In the future, serious problems may arise with the maintenance of power quality, stability and safety of electric utility grids interconnected with low quality private PV power systems, without adequate protection measures being taken. The safety problem is the most important factor for electric utilities in Japan and therefore the reliability of islanding protection of such power systems must be checked because the phenomenon will directly affect the safety of personnel and utility facilities. In order to solve this problem, a reliable and compact protective control unit for residential PV power system application was developed by CRIEPI. It is confirmed that the unit shows excellent reliability for interconnected power system islanding protection.