Changes in fault current levels due to renewable embedded generation in a distribution network

An increased interest in renewable energy such as wind, solar and etc. has reintroduced embedded generation to the power system network. However, traditional networks are designed for power to flow from the grid to the load. The integration of embedded generation into the system brought forth the issue of reverse power flow to system. A reverse flow of power would disrupt the operation of existing protection system in the network by changing the fault currents flowing in the line. This paper investigates the changes to the fault current and the effect of the integration of the embedded generation into existing power system networks. This research uses MATLAB/Simulink to simulate a simple test system network with embedded generation. Initial simulation result shows the reverse power flow lowers the value of the fault current from the grid. This results in a longer tripping time for existing overcurrent relays and possibly disruptions to the coordination of the protection system in the network.