Supplying DC Auxiliary System in Power Station by Using a DC Microgrid

Abstract

Electrical power generation is the first and most important step in producing electricity. Internally, the generation station has an essential sub-system that is called the DC auxiliary system, which is considered the soul of the station and helps in supplying electricity to the essential components in the power station, such as protection elements, monitoring systems, alarms, and control equipment. So, it needs a main and backup source of electrical supply. A challenging problem is discussed in this paper, which is increasing the reliability of the system through the transition to the DC microgrid. This paper aims to provide two different scenarios using renewable energy sources (RESs) for better reliability and economic operation. Both scenarios use photovoltaic (PV) systems with battery energy storage systems (BESSs) to supply the DC auxiliary system in the generation power station. The first scenario supplies the DC loads for 24 hours and the other one only for 8 hours; then, the loads would be supplied by the grid the rest of the day. As a result, both proposed scenarios use DC microgrid, which is applicable, more efficient, reliable, and cost-effective than the conventional source of supply. In addition to choosing, either one of the two scenarios has its own considerations. The first one is more costly than the other, but it is more sustainable over time. Cairo North Power Station Combined Cycle 750 MW in Shoubra, Egypt, is selected in this paper as the case study. Simulation and results are gained using the PVsyst program. The results are manually checked and compared to the simulation report. Also, the economic study over 25 years for the proposed system is added.