A Multi Time-Scale and Multi Energy-Type Coordinated Microgrid Scheduling Solution—Part I: Model and Methodology

TLDR

Optimal microgrid operation faces coupled cooling‑electricity co‑optimization challenges with CCHP units and ice‑storage air‑conditioners, and must accommodate renewable energy randomness. This paper models the partial‑load performance of CCHPs and ice‑storage air‑conditioners and establishes coordinated day‑ahead scheduling and real‑time dispatching models for cooling and electricity. The day‑ahead model represents wind and solar uncertainty with multi‑scenarios to minimize expected operation cost, while the real‑time dispatch applies distinct time‑scale schemes for cooling and electricity to smooth renewable fluctuations, match demand, and reduce grid impact. The resulting multi‑time‑scale coordinated schedule achieves integrated optimization of multi‑energy supply and renders the microgrid controllable from the main grid.

Abstract

For optimal microgrid (MG) operation, one challenge is the supply of cooling and electricity energy is a coupled co-optimization issue when considering the combined cooling, heating and power (CCHP) units and ice-storage air-conditioners. Another challenge is the inherent randomness of renewable energy within the MG should be accommodated by MG itself. In Part I of this two-part paper, the partial load performance of CCHPs and the performance of ice-storage air-conditioners are modeled, and the cooling and electricity coordinated MG day-ahead scheduling and real-time dispatching models are established. In day-ahead scheduling model, the uncertainty of wind and solar power is represented by multi-scenarios and the objective is to achieve the minimal expected MG operation cost. In real-time dispatching model, the different time-scale dispatch schemes are respectively applied for cooling and electricity to smooth out the fluctuations of renewable energy supply and to follow the variations of cooling and electricity demands by the fine dispatching of the components within MG such that the impact of MG to the connected main grid is minimal. The proposed MG multi time-scale cooling and electricity coordinated schedule achieves an integrated optimization for multi energy-type supply, and makes the MG be controllable as seen from the main grid.