混合式抽水蓄能电站过渡过程研究

为了适应电网发展的需求,具备一定地形地质条件的常规水电站可考虑通过增装蓄能机组扩建成混合式抽水蓄能电站。针对共用引水系统的常规机组和蓄能机组实际运行特点,基于特征线法和瞬变流理论,建立了水力过渡过程计算模型,并结合工程实例模拟了混合式抽水蓄能电站可能发生的多种过渡过程工况,确定了合理的蓄能机组的关闭规律,复核了已建调压室的稳定性。结果表明,通过对新增蓄能机组导叶启闭规律的独立调控,一定程度上可维持混合式抽水蓄能电站输水发电系统的安全稳定,避免增设调节保证设施;蓄能机组导叶关闭时间延长,在降低自身蜗壳末端最大压力的同时,可抑制常规机组甩负荷后的蜗壳末端压力及最大转速上升;对于既有调保措施威胁最大的相继增负荷工况,引用流量较大的常规机组优先增负荷比引用流量较小的蓄能机组优先增负荷引起的调压室最低涌浪值更高,更有利于调压室的稳定运行。

Study on Transition Process of Hybrid Pumped-storage Power Station

In order to meet the requirements of power grid development, some conventional hydropower stations with topography and geology condition usually consider setting pumped storage units and expanding into hybrid pumped-storage power stations. In accordance to the characteristics of the conventional unit and the pumped storage unit in common water diversion system during water transients, a calculation model of transition process is established based on the characteristic line method and fluid transient theory. Combined with engineering example, this model is used to calculate the various transient process conditions that may occur in hybrid pumped-storage power station, thus determining the closing law of the pumped storage unit and reviewing the stability of the established surge tank. The conclusions show that as long as the operation control of the new pumped storage unit is reasonable, the safety of water conveyance and electric power generation system of hybrid pumped-storage power stations can meet the requirements. When the closing time of the pumped storage unit is longer, the maximum pressure and the maximum speed rise of the conventional unit are lower, as well as the maximum pressure of the pumped storage unit. For the condition that two units successively increase load, which threatens the existing adjustment guarantee, the conventional unit with larger discharge increased load first raises the lowest wave-level, rather than the pumped storage unit with smaller discharge increased load first, which is conducive to the stable operation of surge tank.