Ac Transmission-Constrained Unit Commitment with Data-Based Linear Power Flow

Abstract

Transmission constrained unit commitment (TCUC) is important in power system daily operations. The power flow models used in TCUC formulations has great impact on the solution of TCUC problems. TCUC problem based on AC power flow equations (AC-PF) yields accurate solution but generally has heavy computational burdens. DC power flow (DC-PF) is a linear approximation of AC-PF and is generally used to formulate TCUC problems. DC-PF brings computational advantages to TCUC problems but also introduces model errors. To relieve the model errors of DC-PF while retaining the advantages of linear formulations, a linear ACUC model is proposed in this paper by adopting the data-based linear power flow (D-LPF) model. In this paper, the D-LPF model is modified to conquer the difficulties of data sensitivity and negative network losses in applying D-LPF to TCUC problem. The proposed linear ACUC model can consider voltage, network losses and reactive power flows, and no base points are required in the model. Case studies, including a 2000-bus system, verify the effectiveness of the proposed method, and results show that the solution quality of the proposed linear ACUC model is close to that of the nonlinear ACUC model under less computational burdens.

Keywords: Unit commitment, linear power flow, mixedinteger linear programming, AC power flow.