尾水主洞长度对抽水蓄能电站尾水管进口最小压力的影响

针对采用"一洞两机"布置形式的无尾水调压室抽水蓄能电站,基于瞬变流理论与特征线法,对实际工程进行数值模拟,分析了不同尾水主洞长度对相继甩负荷工况下尾水管进口最小压力影响的内在机理。结果表明,尾水主洞的增长对尾水管进口最小压力不利,但随着尾水主洞长度的增长,尾水管进口最小压力先减小后增大再减小;随着尾水主洞长度的增长,先甩负荷机组和后甩负荷机组均有可能是引水发电系统出现尾水管进口最小压力的不利机组,整体来看,先甩负荷机组尾水管进口最小压力先减小后增大,后甩负荷机组尾水管进口最小压力先增大后减小。

Effect of Length of Main Tail Water Hole on Minimum Pressure at Draft Tube Inlet in Pumped Storage Power Station

Focusing on a pumped storage power station without tailrace surge tank used the layout of two units per penstock, the numerical simulation was carried out on a practical pumped storage power station based on the transient flow theory and the method of characteristics. The different lengths of the main tail water hole influencing the minimum pressure at the draft tube inlet were analyzed when a successive load rejection happened. The results show that the increase of the main tail water hole length is not conducive to the minimum pressure at the draft tube inlet, but as the length of the main tail water hole increases, the minimum pressure at the draft tube inlet decreases first then increases and then decreases. With the length of the main tail water hole increases, both the first load rejection unit and the second load rejection unit may be unfavorable units for the minimum pressure at the draft tube inlet of the water diversion system. On the whole, the minimum pressure at the draft tube inlet of the first load rejection unit first decreases and then increases, and the minimum pressure at the draft tube inlet of the second load rejection unit increases first and then decreases.