Hierarchical Control of Air-Conditioning Loads for Flexible Demand Response in the Short Term

Increased wind power penetration and load demands lead to an increase in the peak-valley difference, which challenges system stability. This paper presents a hierarchical control strategy to coordinate multiple units of aggregated air-conditioning (AC) loads for power regulation to help reduce the peak-valley difference. First, the independent system operator (ISO) determines the purchased reserve capacity according to the roughly expected regulation effect, and the range of adjustable instructions is derived based on the purchased reserve capacity to help reduce the computation burden. Second, the economy optimizations between the ISO and load aggregators (LAs) are carried out to determine the distribution of purchased control units for AC. Third, after implementing unified planning by the ISO, the LAs deliver the scheduling instructions, including the triggering times and unit numbers, to the AC units to achieve short-term power regulation. Additionally, the scheduling accuracy can be set by changing the scale of the AC control units according to the requirements of the instructions. The simulation results show the effectiveness of the proposed control framework in Lianyungang, with 1000 control units participating. The method proposed in this paper could relieve the burden of the peak-valley difference effectively with less economic expenditure.