Study Of Unit Commitment Problem Considering AC Optimal Power Flow Constraints

The thesis study focuses on the unit commitment problem considering alternating current(AC)optimal power flow constraints,aiming to meet the realistic demand of the power system.The Unit Commitment(UC)problem refers to the selection of suitable units to meet the power supply demand according to the system load demand,with the aim of minimizing the total operating cost of the power system.However,in reality,the traditional generation-side unit commitment problem is no longer sufficient to meet the actual demand of the power system.There are complex AC power flow constraints in the power system,which are determined by the operation of transmission lines,transformers and other equipment,and these constraints need to be taken into account to obtain more realistic dispatch results.To solve the above problems,this thesis firstly introduces the background and research status of the unit commitment problem and AC optimal power flow calculation.Secondly,the mathematical modeling of the unit commitment problem is carried out,and the linearization transformation is carried out for the nonlinear constraints in the model using the segmental linearization method.Subsequently,the first-order Taylor expansion and successive linearization methods are used to linearize the nonlinear part of the AC optimal power flow model and establish the mixed-integer linear model of the AC optimal power flow.Then,the unit commitment model and the AC linear optimal power flow model are integrated to construct a Mixed Integer Linear Programming(MILP)model for the unit commitment considering the AC power flow constraints and solved by Gurobi commercial solver.Finally,the results of this thesis are summarized and improvement directions are proposed.This thesis aims to optimize the unit commitment problem by introducing AC optimal power flow constraints.Specifically,the AC optimal power flow constraints are added to the original generation-side unit commitment model,and the linearization method is used to linearize the model to obtain a linear unit commitment model with AC optimal power flow constraints,so that the model can consider both unit commitment and AC optimal power flow constraints,and obtain a day-ahead generation schedule that is more consistent with the actual power system.