Fault ride through requirements and measures of distributed PV systems in Japan

Photovoltaic (PV) power generation system is expected to be penetrated widely and largely for coping with the global environmental issues, etc. Those PV systems may stop the operation or be in unstable operation simultaneously in case of the grid transient disturbances such as voltage sag, etc. Those matters may impact on the gird stability seriously under the large penetration. In Japan, fault ride through (FRT) requirements on voltage sag and frequency variation for PV systems connecting to single phase low voltage distribution line were recently investigated and proposed by a governmental support project. Toward establishment of proper measures to meet the FRT requirements, operation characteristics of many types of current Japanese power conditioning subsystems (PCSs) for residential PV system under various transient disturbances are tested and evaluated. Fundamental measures for enhancing FRT performance of the PCSs are also investigated and proposed.