An Arbitrary Segmented Ramping Model For Unit Commitment

In the power systems field,due to the greenhouse gas emissions and air pollution caused by traditional energy sources,it is urgent to build a new system with a high percentage of renewable energy penetration to reduce environmental pollution and dependence on fossil fuels.Renewable energy(such as wind and solar)has the advantages of clean,sustainable,and low carbon emissions.However,due to these energy sources’ intermittent and volatile nature,they cannot independently undertake the power generation task and still need the support of traditional energy sources such as thermal power stations to ensure a stable supply and demand relationship in the grid.Consequently,it is significant to clarify the supply retention capacity of thermal power stations for the new power system to calm the fluctuation of renewable energy and enhance the proportion of renewable energy consumption.This thesis fully considers the characteristics of coal-fired units.It develops a unit commitment optimization model on this basis,analyzing in detail the model’s objective function,constraints,and decision variables and providing theoretical support for assessing the actual response speed of thermal energy.In order to calculate the actual response speed of thermal power stations,this paper proposes a unit commitment model with an intraperiod multiple-segment ramping function based on the current concept of the dynamic piecewise linear ramping(DPWLR)model.First,according to the generator characteristics,divide the unit output interval and set the corresponding ramping speed,construct a multi-segment linear ramping function,and establish an intraperiod single-changing DPWLR model and analyze its logic.After that,the Special Order Set Type 2 principle is applied,the multiple-segment ramping function is used as the theoretical basis for the unit ramping constraint to calculate the real-time ramping capacity of the unit,and the optimal solution for power distribution is solved with the economic optimum as the optimization objective to build the intraperiod multiple-changing DPWLR model proposed in this paper.Finally,the new model is validated by several test systems with different sizes and load characteristics.The results show that the model can completely simulate the natural unit ramping process and obtain a more accurate unit dispatching scheme,which provides a new research idea to clarify the actual response rate and supply retention capacity of thermal power stations.The model provides new research ideas for new power system consumption challenges.