368 / 2024-02-29 21:44:19

Dominant factors identification of refill operation of cascade reservoirs based on Sobol' sensitivity analysis

cascade reservoirs; dominant factors; global sensitivity analysis; Sobol’; refill operation; optimal operation

In the study aimed at identifying the dominant factors of the refill operation of cascade reservoirs, it is challenging to consider the interaction between various parameters using the local sensitivity analysis method. To improve the applicability of the optimal operation model for the cascade reservoirs, Sobol's global sensitivity analysis method was utilized to quantitatively evaluate four uncertain factors that impact refill operation in the cascade reservoirs: the start time of refill operation, initial control water level during the refill period, inflow uncertainty, and the water elevation-storage relationship curve. A case study of the Qingjiang cascade reservoirs indicated that the start time of refill operation and the relative error of input runoff are sensitive parameters for the refill operation of the cascade reservoirs, with the relative error of input runoff playing a dominant role. Its contribution rate to the variance of the hydropower during the refill period and the spilled water of the cascade reservoirs is 79.41% and 61.70%, respectively. The impact of the initial control water level during the refill period and the error of the water level storage-capacity relationship curve on the output of the refill operation model is small. For the refill operation of cascade reservoirs, the focus should be on dominant factors such as the start time of refill operation and input runoff to improve the practicality of the refill operation model. The research findings can provide reference for refining input parameters in the refill operation model of cascade reservoirs.