Investigation of factors leading to the hard unit commitment problem

The unit commitment (UC) problem is a typical mixed integer linear programming (MILP) problem in power systems. It often encounters significant computational challenges in power industries. With the development of power systems, the structure of the UC model and the scenarios that need to be considered become more complex and unpredictable, which increases the hardness of the UC solution. However, a systematic investigation of the key factors determining UC solution difficulty remains a hanging problem, limiting the development of targeted efficient algorithms. This paper presents a comprehensive analysis of three critical factors determining UC computational complexity: constraint stress, root relaxation quality, and convergence criteria. Through the indicator definition, this paper quantitatively evaluates proposed key factors and reveals the influence mechanisms of the proposed key factors on the hardness of UC solution through extensive case statistical analysis. The analysis of this paper provides effective references for efficient and customized UC solution algorithms.