可逆式机组飞轮力矩的合理取值及敏感性分析

为了控制抽水蓄能电站中的大波动水力过渡过程，改善小波动稳定性，常考虑增大可逆式机组的飞轮力矩 GD2，但会造成投资增加。因此，有必要对机组 GD2 的合理取值及对调保参数的敏感性开展研究。在统计分析了 20 座涵盖高、中、低水头的可逆式机组的抽水蓄能电站相关设计参数的基础上，利用系统辨识的最小二乘法建立了可逆式发电－电动机 GD2 新的经验模型。继而，以实际工程为例，通过对机组 GD2 在不同取值情况下的甩负荷过渡过程进行了对比计算，分析了机组转速、蜗壳和尾水管进口压力、尾水调压井最高、最低涌浪水位等对 GD2 的敏感性。结果表明，本文提出的经验模型预测可逆式发电－电动机 GD2 的效果最佳，可作为初步设计阶段可逆式发电－电动机 GD2 的取值依据。尾水管进口最小压力和机组最大转速上升率对于 GD2 的变化最为敏感，而机组 GD2 对蜗壳最大压力、尾水调压井最高、最低涌浪水位等的影响较小; 机组 GD2 的最终取值及优化还需结合电站水力过渡过程计算综合确定。

Reasonable value selection and sensitivity analysis of flywheel moment of inertia for reversible pumped-storage unit

To control the largely fluctuated hydraulic transition process of pumped storage hydropower station and improve the stability of the small fluctuation，it is often considered to increase the flywheel moment of inertia ( GD2 ) of reversible pumped-storage unit，but the relevant investment is to be increased． Therefore，it is necessary to study the reasonable value of the GD2 of the unitand the sensitivity to the relevant parameters of regulation and guarantee． Based on the statistical analysis of the relevant design parameters of the high，medium and low head reversible pumped storage units from 20 pumped storage hydropower stations， a new empirical model of the GD2 for the reversible generator-motor is established with the least square method for the system identification． Afterwards，the load rejection transition processes of the GD2 of the unit under the conditions of different values are comparatively calculated by taking an actual project as the study case，and then the sensitivities of the rotational speed of the unit，the inlet pressures at both the spiral case and the draft tube，the highest and the lowest surge levels of surge shaft to the GD2 are analyzed． The study result shows that the effect of the empirical model of GD2 proposed herein for predicting the GD2 of reversible generator-motor is the best，and then can be taken as the basis for the parameter selection of the GD2 of reversible generatormotor． Both the minimum pressure at the inlet of draft tube and the maximum rising rate of rotational speed of the unit are most sensitive to the change of the GD2 ，while the impact from the GD2 on the maximum pressure of spiral case，the maximum and the minimum surge levels of surge shaft is less． However，the final parameter selection and the optimization of the GD2 of the unit are still necessary to be comprehensively determined in combination with the calculation of the hydraulic transient process．