Enhanced-decision energy trading for island renewable microgrids considering large interruptible refrigeration load intra-hour switching

Abstract

Large interruptible refrigeration load (LIRL) can be incorporated into the scheduling model of microgrid (MG) to optimize the operational cost. However, based on a classic 1-hour step, the LIRL is either turned on or off, resulting in unsatisfactory results. Although a smaller scheduling step can adjust the LIRI more finely, the computational burden will be increased simultaneously. To address the problem, this paper proposes a novel enhanced-decision energy trading strategy for renewable MGs. First, enhanced decisions are proposed, where on-state and off-state durations of LIRL in an hour instead of on or off state would be determined. On the basis, based on a 1-hour scheduling step, an enhanced-decision trading model is presented, where the energy operator maximizes the electricity sale profit, and load aggregators (LA) minimize the electricity usage cost. This optimization model is first converted into a classic mixed-integer quadratic programming (MIQP) problem, and then solved by a distributed method. Simulation studies indicate that the proposed energy trading strategy can reduce the electricity price fluctuation range by 0.43 yuan (20.6%), increase the social cost by 104 yuan (3.5%), and benefit the participators.