Fault analysis when a mini grid is connected to the main grid
Abstract
Increased exploitation of renewable energies for electricity generation has resulted into increase in the number of mini grids which can be operated in island mode or in grid connected mode. When mini grids are connected to the main grid, the fault current levels may increase. West Nile Rural Electrification Company (WENRECo) is used as the mini grid whose generation capacity is less than the demand and thus need for it to be connected therefore making it essential to do a fault analysis prior to its connection to the main grid.
In this project, the WENRECo network, the main grid network and the connected model were built in DigSILENT power factory simulation software. A fault analysis was made putting focus on fault MVA and fault currents. Protection coordination of the network before and after the connection to ensure that the circuit breakers and relays operate appropriately in case of a fault was also made. We suggest use of series reactors to help to reduce on the fault current levels.