Optimal operational planning of scalable DC microgrid with demand response, islanding, and battery degradation cost considerations

With the advancements in power electronic devices, the increasing use of DC loads, DC renewable generation sources and battery storage systems, and no reactive power and frequency stability issues, DC microgrids are increasingly gaining attention in both academia and industry. In this paper, a grid-connected DC microgrid is considered, which consists of a PV system and a Li-ion battery. DC microgrids optimal operation requires battery degradation cost modeling and demand response incentive for active consumers' participation to be addressed in detail. Therefore, a practical degradation cost model for a Li-ion battery is developed to optimize battery scheduling and achieve its realistic operational cost. Apart from energy price, scheduled islanding responsive demand response incentive is also introduced to encourage customers to shift load during scheduled grid-tie line maintenance. Levelized cost of energy of PV system is calculated for both hot and cold climate regions. Optimal operation of DC microgrid cannot be achieved without considering nodal voltages and system losses. Hence, network constraints are also included in the proposed model. Extensive numerical simulations are carried out to prove the effectiveness of the proposed approach. The achieved results would aid in DC microgrids adoption planning that would expectedly replace traditional AC grids in the future.