In high-velocity and hyper-concentrated flow long-term erosion,the guide vane rigid facade seal surfaces of Wanjiazhai hydraulic turbine wore seriously by sand abrasion and cavitations,which caused water leakage increased and the appearance of unit shunt running,so the safety running of units was being seriously affected. The guide vane rigid facade seal surfaces wore seriously after a minor repair cycle when the welding polishing repair treatment was adopted. Therefore, in order to solve the above problems, it was necessary to reform the guide vane facade seal to ensure the safe operation of the turbine units and reach the purpose of energy saving and efficiency increasing. The reason of sealing failure was analyzed, then a viable technology solution was put forward and the steel-plastic composite polyurethane seal plates invented by Yellow River Institute of Hydraulic Research were used firstly for the improvement of No.1 and No.4 units and the technical details and the installation process were controlled precisely and strictly. After two flood seasons running test,the results show that this seal-ing sets improve the sealing performance under the conditions of full closed wicket gate and restrain the abrasion and leakage. This technical transformation is very useful for the sealing failure of wicket gate for Wanjiazhai Hydropower Station and provides a reference of guide vane seal transformation for other hydropower stations.%万家寨水电站水轮机组在高速高含沙水流长期冲刷作用下,活动导叶的刚性立面密封面磨损汽蚀严重,造成导叶漏水量加大,导致机组出现"潜动"问题.在分析导叶密封失效原因和总结传统堆焊打磨修复处理方式缺陷的基础上,提出了活动导叶立面密封技术改造方案,首次采用黄河水利科学研究院自主研发的钢塑复合聚氨酯导叶密封板,对1#和4#机组进行技术改造,对改造的技术细节和中间安装过程进行了精确控制和严格质量把关.经过两个汛期运行检验表明:活动导叶立面密封技术改造提高了导叶全关状态下的密封性能,可以有效抗磨和抑制漏水,解决了活动导叶密封失效的问题.
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