Multiple-Stage Inter-temporal Flexibility for Planning: A Non-sequential Probabilistic Production Simulation Approach

High wind energy curtailment during winter and early spring in north China has drawn widespread concern in recent years, which, at source, results from the shortage of power system flexibility. Therefore, power system needs to consider the flexibility in planning stage. However, current flexibility metric is difficult to calculate and be applied in to the optimal planning. A non-sequential production simulation model with only input data of the cumulative probability function and/or probability density function of heat demand, electricity demand, and wind power is proposed, which is used to obtain the probability distribution of the production for generators according to least cost principle. Then the flexibility metric can be easily calculated based on the production results. Simulations were performed based on the actual data of a large wind power zone in north China. Multiple flexibility metric was evaluated and compared with the wind power curtailment, which shows the strong correlation between them. Finally, the impact of flexible resources on the flexibility metric was analyzed.