Two-Stage Secure Bottom-Up Load Coordination Mechanism in Distribution Grids

Demand-side flexibility as a new source of ancillary services is attracting growing attention. Aggregation and coordination mechanisms are needed to efficiently use the demand side flexibility. This paper proposes a new secure two-stage bottom-up coordination mechanism that ensures the quality of service (QoS) for customers and facilitates improved services for both distribution and transmission system operators. In the first stage of the proposed method, the interaction between aggregators and controllable loads is addressed. In the second stage, the interactions between the DSO and aggregators are addressed. Commitments of the aggregators to follow their scheduled power in the electricity market are also taken into account in the proposed framework. The proposed method is applied to a test system with two areas supplied by two transformers with some uncontrollable loads, 70 PV/battery setups, and 80 heating systems supplied by heat pumps (HP) that are in contract with two aggregators. Simulation results highlight the effectiveness of the proposed method in preventing transformers’ overload and reducing their loading by up to 27% while increasing the total electricity cost of customers with controllable devices by about 4.6%.