Microgrid for Alcântara Launch Center in Brazil

Some microgrid challenges arise when operating isolated from the main grid precisely because the local distribution network becomes an ungrounded delta circuit and the microgrid power sources have low short-circuit capacity. The main problems are the non-detection of ground overcurrent in an earth fault event, the unbalance between voltages measured by voltage transformers connected between phases-to-earth, and black start. These issues were resolved through adjustments in the protection relays of the sources and medium voltage circuit breakers, in addition to the implementation of effective control strategies in the Energy Management System.