Hydro-Thermal Joint Optimization of Multi-objective Unit Commitment Considering Negative Peak Load Regulation Ability

After the large-scale new energy power connected to the grid, the power system will face great challenges in terms of security and stability, power quality, peak load regulation and frequency modulation. In order to ensure safe and reliable operation, the power system needs to reserve more adjustable space to cope with the uncertainty of new energy. The adjustable output of available units at the valley time of the system determines the ability of new energy absorption to a large extent. Therefore, the key to improve the consumption of large-scale new energy is to solve the problem faced by the system's peak load regulation. It depends not only on the existing system structure, but also on the reasonable unit commitment scheme. In order to keep an economically and reliably operation, this paper studies a multi-objective unit commitment model which considers the operating cost of the system as well as the negative peak load regulation ability. A hydro-thermal joint multi-objective optimization method based on normalized normal constraint method is also presented. Decision makers can choose a appropriate unit commitment results from the Pareto frontier as the final scheme with a comprehensive consideration of operation cost and negative peak load regulation ability. An example analysis is carried out in the test system with 10 thermal units and 2 hydro units, which verifies the feasibility and efficiency of the proposed model and method.