A New Method for Controlling Microgrids Protection Settings with the High Penetration of Distributed Generation

In recent years, the distributed generation resources (DGR) have become an essential and inseparable component in power networks and have achieved major success. Improving network power voltage, helping in peak load conditions and reducing load on power lines and transformers, utilizing renewable energies and reducing environmental pollution constitute some of the reasons for their expansion. In contrast to all these advantages in a given network, the increased presence of distributed generation resources has presented new challenges for power networks. One of the most important problems is the impact on system protection functionality. The traditional protection structure of the networks will be impaired and malfunctioned due to the presence of distributed generation resources. In this paper, a new intelligent linear control algorithm is used to restore the protective coordination. The proposed method modifies the protection characteristic curve of the protection system by adjusting the overcurrent relay current coefficient. This control procedure is in accordance with the widely applied over-current relay curves and complies with the relevant standards. For this purpose, by using a new drop control block and local sampling of over-current relay current, current setting of the relay is recovered to keep the correct operation of protection system. The proposed method is evaluated on two real micro-grids test system in Isfahan province by ETAP software. The findings indicate the ability of this method in coordinating the protection functionality of micro-grids with high penetration coefficient of DGR.