抽水工况双馈可变速抽蓄机组机电暂态建模及有功–频率耦合特性

Electromechanical Transient Modelling and Active Power-frequency Coupling Characteristics of Doubly-fed Variable Speed Pumped Storage Under Pumping Mode

传统定速抽蓄机组在抽水工况下输入功率无法连续调节,不具备参与电网调频能力。双馈式可变速抽蓄机组是一种新型的水电系统,由于抽水工况下转速连续可调,在保证静态扬程的前提上,通过变速运行,机组输入功率调节范围拓宽。为挖掘机组参与电网调频潜能,首先建立抽水工况可变速机组的简化机电暂态模型,该模型以抽水工况可逆水泵水轮机运行特性为基础,考虑了流体在过流管道内的动态特性,并计及导叶的附加摩擦效应;然后从水力的角度揭示了抽水工况机组具备调频能力的本质原因;阐明了抽水工况机组改善电网频率特性的机理,并给出了控制器参数的推荐范围。最后,仿真和实验结果验证所提抽水工况机组改善电网频率特性的能力。

The input power of the conventional constant-speed pumped storage unit cannot be continuously adjusted under the pumping mode, and it does not have the ability to participate in frequency control of the grid.Doubly-fed variable speed pumped storage unit is a new type of hydropower system. Because the speed can be adjusted continuously, the input power of the unit under pumping mode can be adjusted more widely on the premise of ensuring the static head. In order to explore the potential of the unit in participation in grid frequency control, a simplified electromechanical transient model of the unit in pumping mode was first established. Based on the operation characteristics of reversible pump-turbine in pumping mode, the dynamic characteristics of the fluid in penstock were considered, and the additional friction effect of guide vane was taken into account.Then, the essential reason why the pumping mode unit had the ability to carry out frequency control from the perspective of hydraulic was revealed. Next, the mechanism of the unit in improving the frequency characteristics of the grid was expounded, and the recommended range of controller parameters was given. Finally, the simulation and experimental results verified the capability of the proposed pumping mode unit in improving the frequency characteristics of the grid.