Protection coordination scheme for distribution networks with high penetration of photovoltaic generators

The installation of photovoltaic (PV) systems is gaining great attention due to the matured PV technology and the lowered price of PV modules. With an increasing penetration of PV systems, the selectivity of distribution network protection may be affected which results in undesirable de-energisation of loads, damage of network equipment, and reduction of reliability. This study presents a method to preserve the protection coordination considering future PV systems installation with any penetration level and different locations along the distribution feeder. Depending on the accessibility of protection device settings or PV control parameters, the proposed method modifies the existing characteristic curve of overcurrent devices or limits the output current of PV sources, respectively. The proposed strategy does not change the structure of existing distribution network protection system and can also be implemented in the old and non-programmable relays. Meanwhile, it does not need the communication links. The merits of the proposed method are demonstrated through several case studies using the Isfahan distribution network.