A resilient DC community grid with real time ancillary services management

The restructuring of the electric supply industry has prompted the situation where customer is a critical business player. This has also made the maintaining of reliability and stability in the power system a monetarily crucial task. Self-resilient community grid is a realization of reliable and stable system at the customer's level as individual households with solar photovoltaics or other renewable system can sustain itself even if the power grid fails. In this paper, a novel DC community grid has been proposed which is capable of providing ancillary services to the main distribution grid. The proposed DC community grid consists of 100 houses with individual solar installation along with a centralized DC-wind turbine and EV charging stations. Load flow analysis was conducted on the community grid using DC power flow method. The individual homes were restructured into a novel hybrid AC/DC home grid which was proved experimentally to have better harmonic reduction, more power resilience and efficiency. A bidirectional three phase voltage source inverter is used for grid interconnection whenever there is an ancillary service request from the distribution system operator or there is a shortage of power within the community. Fault ride through capability of the community grid tied inverter was tested for line-line and three phase bolted fault which is a common interruption in the distribution network. The analysis was done using MATLAB/Simulink. This paper succeeded in establishing the feasibility of connecting individual homes into a community grid for better efficiency and distribution grid reliability.