Research on Multi-time Scale Flexibility Scheduling Strategy for New-type Power System Considering Penetration Rate Stage Division

With the promotion of the dual-carbon goal, the penetration rate of renewable energy sources (RESs) in the new-type power system will continue to increase, and therefore the supply and demand situation of flexibility will become increasingly severe. More flexibility is required to address the demand fluctuations resulting from the unpredictability of RESs output, which makes dispatching department place a greater emphasis on security risks. Therefore, dividing the penetration rate of RESs into different stages is crucial to accurately portray the flexibility relationship between supply and demand from a dispatching perspective. Different characteristics are exhibited by the flexibility supply and demand of the new-type power system at different penetration rates. In the low rate stage, as flexibility is relatively sufficient, the scheduling strategy considering economic benefit can be adopted; while in the high rate stage, the allocation of flexibility resources and the application of flexibility scheduling strategies are required due to insufficient flexibility. In this regard, this paper proposes a new approach to delineate the grid connection levels of renewables with the aim of counteracting volatility and mitigating its impact. A multi-time scale scheduling strategy for RESs penetration rate is proposed. Once the system enters a high percentage of RESs integration, the dispatching strategy must be adjusted according to the variation of the flexibility supply-demand relationship. The simulated results validate the effectiveness of the proposed dispatching method.