A Two-Stage Approach for Network Constrained Unit Commitment Problem With Demand Response

Abstract

This paper proposes a two-stage formulation for the day-ahead energy scheduling problem with demand response (DR). The first stage solves a network-constrained unit commitment problem with DR, to determine the hourly net demand changes (i.e., difference between final and initial demand values) happening at each DR bus 1 along with the unit commitment schedule and ac load flow solution. Here, the objective is to maximize the social welfare which is expressed as the total utility of the demand side minus the total generation cost. The second stage solves an incentive or penalty minimization problem to determine the demand shifting and demand curtailment across the 24-h period at each DR bus, offering DR, based on the hourly net demand changes obtained during the first stage. The proposed formulation shows how demand shift and demand curtailment happening at different DR buses can be traced back to the hourly net demand changes occurring at the system level. The results, presented for a six-bus system and IEEE 118 bus system, show the benefits of including DR into the network-constrained unit commitment problem according to the proposed formulation. 1 Any bus which is capable of offering DR will be referred to as DR bus. It should not be mistaken for PQ bus referred in the load flow analysis.