Evaluating energy supply service reliability for commercial air conditioning loads from the distribution network aspect

Abstract

The limited amount of dispatching flexibility has encouraged the development and implementation of demand response in the distribution system. Commercial air conditioning loads are promising demand response resources and tend to have greater potential for centralized regulation. From the perspective of distribution networks, evaluating the reliability of energy supply services for air conditioning loads should be of much concern because reliable services would directly affect the customers’ tendency to demand response. However, traditional load reliability evaluation does not fully explore the fact that the energy supply processes of air conditioning loads can be flexible. Modeling the energy demands as flexible loads, a reliability assessment algorithm for commercial air conditioning loads is proposed for distribution systems in this paper. The “loss of load” event is innovatively defined considering customer preferences. Novel systematic indices are established that are specialized for describing the reliability of energy supply services. Afterward, a two-stage control strategy is proposed considering the comfort requirements of customers, which would affect reliability performance. The first stage optimizes the operating state of the air conditioning system internal equipment collaboratively, while the second stage sacrifices some comfort for sufficient utilization of the thermal self-storage capacity and load rebound suppression. Finally, the proposed method is validated in a standard test system with voltage violation risks. The results demonstrate the impacts of different control strategies on the reliability performance of commercial air conditioning loads. Analysis drawn from the sensitivity of load reliability indices can assist distribution system operators in coordinating energy supply reliability and dispatching requirements.