向家坝水电站机组低水头过速试验导叶关闭规律异常分析

Analysis on Abnormal Closing Curve of Guide Vane during Unit's Over-speed Test under Low Water Head Condition of Xiangjiaba Hydropower Station

向家坝水电站的部分机组在低水头进行过速试验时出现了导叶关闭规律异常现象。通过实测数据和模型试验分析,机组在过速试验过程中接力器出现反向回开与反泵工况有关。机组在低水头下进行过速试验,导叶小开度时进入反水泵工况,导致导叶关闭规律出现异常。随着运行水头的增大,该异常现象也随之消失。

The abnormal closing curve of guide vane appears in over-speed test of unit under low water head condition in Xiangjiaba Hydropower Station. Based on the model test data and theoretical analysis, the abnormal closing of guide vane is mainly caused by the re-opening of servomotor which is thought to be related to the operation condition of reverse pump mode. The turbine will operate in reverse pump mode when the water head is low and the opening of guide vane is small in over-speed test, and the reverse pump mode will cause abnormal closing of guide vane. With the increase of operation head, this abnormal closing is also disappeared.