抽水蓄能电站压力钢管焊缝应力测试与评价分析

Welding seam stress measurement and evaluation of penstock in a pumped-storage power station

为确保抽水蓄能电站机组通流部件的稳定运行,对球阀与压力钢管连接位置处焊缝应力进行了测试,利用球阀全开导叶全关时的静水压力对应力测点进行标定,进而获得了甩负荷情况下焊缝位置处的应力变化特征。数据分析结果表明:焊缝处各测点环向应力与球阀前压力呈正相关,相关系数大于0.94;焊缝处顺水流方向应力与压力呈负相关,相关系数小于-0.85;稳态发电工况及甩负荷过程中应力测点中存在明显的动静干涉频率成分;受水锤影响,最大应力变化产生于甩满负荷工况;最大应力值分析表明,压力钢管可以长期安全稳态的运行。

In order to ensure the safe operation of water passage component of hydropower units in pumped - storage power sta-tion ,stress measurement of welding seams at connection position of ball valve and penstock was performed. Stress measuring points was calibrated by hydrostatic pressure in fully opening of guide vanes and fully closing of ball value. Then the stress char-acteristics of welding seam area were obtained in the case of load shedding. The data analysis indicate that circumferential stress has positive correlation with water pressure by correlation coefficient larger than 0. 94 and flow - direction stress has negative cor-relation with water pressure by correlation coefficient less than - 0. 85 ; rotor - stator reaction f r e q u e n c y exists in stable generating condition and load rejection process; u n d e r the influence of wa t e r hammer, the maximum stress deviation ha p p e n s in load rejec-tion process; the maximum stress analysis shows that the penstock can run safely in long term.