Electric Power System Studies for a Multi-MW PV Farm and Large Rural Community with Net Zero Energy and Microgrid Capabilities

Solar photovoltaic (PV) systems are currently being deployed at an accelerated rate because of their cost-competitiveness and environmental benefits, which make them a prime candidate for local renewable energy generation in communities. Microgrids can help accommodate for the problems that accompany PV systems, such as intermittency due to weather, by coordinating different distributed energy resources (DERs), while islanded or by drawing power from the utility while in grid-connected mode. An islanding option is also important for resilience and grid fault mitigation, even if other DERs are not present within the system. This paper studies the potential benefits that a multi-MW utility-scale PV farm may yield for a large rural community when installed within a grid-connected microgrid structure. The PV system was optimally sized based on net present cost (NPC) with a net zero energy (NZE) goal. With local solar PV generation and a connection to the grid to transmit overgeneration through, the community can be NZE by having a PV farm power rating that is much greater than the peak load demand. This may lead to cases of increased transient severity during mode transitions and may require substantial curtailment of PV. A control scheme is proposed to smooth system transients that result from the switching between the two modes of operation in order to avoid system damage or unreliable load service.