Due to the increase in the integration of renewable energy to the grid, there is a critical need for varying the existing methods and techniques for grid operation. With increased renewable energy, mainly wind and photovoltaics, there is a reduction in inertia as the percentage of inverter-based resources is increasing. This can bring about an issue with the maintenance and operation of the grid with respect to frequency and voltage. Thus, the ability of inverters to regulate the voltage and frequency becomes significant. Under normal operation of the system, the ability of the inverters to support the grid frequency and voltage while following the grid is sufficient. However, the operation of the inverters during a resiliency mode, under which there is an extended outage of the utility system, will require the inverter functionality to go beyond support and actually maintain the voltage and frequency as done by synchronous machines, acting as the grid-forming inverter. This project focuses on the operation of grid forming sources based on the virtual synchronous generator to regulate the voltage and frequency in the absence of the grid voltage through decentralized control of the inverters in the distribution feeder. With the most recent interconnection standard for the distributed generation, IEEE-1547 2018, the inverter-based generation can be used for this purpose. The simulations are performed in the Simulink environment and the case studies are done on the IEEE 13 node test-feeder. / Master of Science / With the increase in the renewable energy sources in the present grid, the established methods for the operation of the grid needs to be updated due to the changes that the large amount of renewable energy sources bring to the system. Due to the While the conventional resources in the power system was mainly synchronous generators that had an inherent characteristic for frequency support and regulation due to the inertia this characteristic can be lacking in many of the renewable energy sources that are usually inverter-based. At present, the commonly adapted function for the inverters is to follow the grid which is suitable in case of normal operation of the power system. However, during emergency scenarios when the utility is disconnected and a part of the system has to operate independently the inverters need to be able to regulate both the voltage and frequency on their own. In this project the inverter-based control, termed as the virtual synchronous generator, has been studied such that it mimics the well-established controls for the conventional generators so that the inverter-based renewable resource appears similar to the conventional generator from the point of view of the grid in terms of the electrical quantities. The utilization of this type of control for operation of a part of the feeder with each inverter-based resource controlling its output in a decentralized manner is studied. The controls try to mimic the established controls for conventional synchronous machine and use it for maintain operation of the system with inverters.