I. Introduction
According to the time scale, the power system operation simulation is divided into three stages [1]: long-term, medium-term and short-term ones. The long-term operation simulation includes unit maintenance plan, reservoir dispatching plan and annual power breakdown plan [2]. The short- and medium-term operation simulation includes monthly unit commitment and day-ahead unit commitment. The medium-term operation simulation is used to solve the monthly power allocation and reservoir water consumption. Short-term simulation of power system operation was used for solving some problems of day-ahead generation plans, energy storage charging/discharging plans and demand response of interruptible load. In fact, the unit commitment is the core of the short term phase of the operational simulation [3]. The current method is to apply the long-term operation simulation results as boundary conditions for both short- and medium-term operation simulation. Short- and medium-term unit commitments are rolled out to form the start-stop and output plans for the whole year.