Resilient Dispatch of Off-Grid PV-Storage-EV Microgrids: Hierarchical Load and V2G Coordination

The off-grid operation problem of an integrated photovoltaic storage and charging microgrid suffers from the conflict between power dynamic fluctuation and power supply of multi-priority loads. In this paper, a cooperative optimization method integrating load hierarchical management and electric vehicle two-way interaction (V2G) is proposed to focus on solving the balance problem between power supply finiteness and reliability of microgrids in off-grid situations. The method prioritizes loads into three tiers: life safety, basic security and flexible and adjustable, and constructs a dynamic complementary model of optical storage and on-board energy storage. Two scenarios of extreme and normal operation are simulated: when PV and storage power supply is insufficient, the system prioritizes cutting off adjustable loads and calling V2G charging piles to send power in the reverse direction to support base loads; when renewable energy is sufficient, V2G charging piles are guided to charge in an orderly manner. Test data show that the continuous power supply rate of critical loads under the improved strategy reaches 100%, the system off-grid duration is improved compared with the traditional scheme, and the utilization rate of flexible loads is stable. The results provide new ideas for the flexible design of distributed energy systems.