An adaptive optimization system and point tracking technique for estimation of variable-speed seawater pumped storage

Abstract

There are few kinds of researches on the capacity optimization of seawater pumped storage with variable-speed units. First, the pumped storage effects are investigated to smoothing the large-scale offshore wind power. From the perspective of energy saving and improving efficiency, a method on maximum efficiency tracking is proposed, based on the synthetic characteristic curve of the pump turbine. Second, under the background of the time-of-use electricity price in the power market, the relevant model is established, taking full account of the characteristics of random seasonal fluctuation of tailwater level. Besides, this model satisfies the constraints of variable-speed units (especially under the pump mode). Finally, the key factors influencing profit growth, such as the fluctuation rate, the unit type, and the optimal capacity, are investigated based on a real case. The results show that the variable-speed unit can give full play to the efficiency advantage when the operating head and power demand of the plant change sharply. Because the output range of the variable-speed unit is extensive and can be continuously adjusted (especially in pump mode), the joint system will actively curtail the offshore wind to seek the maximum profit.