龚嘴电站7号机组高负荷异常噪音分析及处理

Analysis and Treatment of Abnormal Noise in the No.7 Hydro-turbine Unit under the High Load Working Condition in Gongzui Hydropower Station

龚嘴电站7号机组增容改造运行几年后,高负荷区域运行时,水车室监测到明显的异常噪音,且幅值较大,影响机组的安全运行。通过对水轮发电机组的稳定性测试,分析噪音和振动的幅值与频率特性,认为异常噪音由卡门涡引起,发生部位为+Y方向的固定导叶出口边。停机检修发现,+Y方向18号固定导叶有多条贯穿性裂纹,经修复前后的固有频率测试,发现修复前后固有频率差异较大,而修复后异常噪音消失,验证了该固定导叶出口边的卡门涡是引起异常噪音这一结论。

In the No. 7 hydro-turbine unit in Gongzui Hydropower Station, abnormal noise with large amplitude is ob- served when it is operated under the high load working condition. Analysis on the amplitude and frequency characteris- tics of the noise and vibration shows that the noise is caused by the Carmen vortex occurred in the outside edge of the sta- tionary guide vanes in the ＋ Y direction. In the overhauling of the unit, several penetrative cracks are found in the No. 18 stationary guide vane in the ＋ Y direction, which are then repaired correspondingly. Test on the unit shows that the natural frequencies before and after the repairing are of great difference. The abnormal noise is also successfully removed after the treatment.