High fidelity modeling of pumped storage units for optimal operation of a multi-energy co-generation system

Abstract

Pumped storage, as the storage technology with the largest installed capacity and mature technology, plays a key regulation role in the multi-energy co-generation system. The core of regulation accuracy is the high-fidelity modeling of pumped storage. This paper improves the insufficiency of the conventional pumped storage model (CPSM) in exaggerating the flexibility of pumped storage units by setting up non-operable operating condition regions, and incorporates the condition switching loss into the model consideration, on the basis of which a high fidelity pumped storage model (HFPSM) is established. Secondly, a multi-objective function of the operation model is set from the consideration of economy, environmental protection and stability, and a engineering application level optimal operation model of wind power-photovoltaic-thermal power-pumped storage multi-energy co-generation system based on HFPSM is proposed. Thirdly, two research indicators, the thermal power volatility indicator and the pumped storage unit utilization rate, are proposed. Fourthly, combined with examples, the effects of CPSM and HFPSM on the optimized operation of the system are investigated. It is found that adding four 50MW pumped storage units to the system can reduce the total operating cost by 10.34% and the environmental cost by 83.61%. The optimization of the high fidelity model is better under the premise of ensuring safe, stable and efficient operation of the system. Optimizing the number of unit startups and shutdowns for the high fidelity model to 25.8% of the conventional model. Finally, by exploring the optimal operation of a multi-energy co-generation system with different pumped storage installed capacities, it is found that the proposed high fidelity model makes the optimization results more in line with the actual operation. The flexibility of the pumped storage units no longer increases with the increase of installed capacity, which provides a reference for the planning of the storage capacity in the multi-energy co-generation system.