基于光纤光栅技术顶盖螺栓载荷智能监测系统工程应用的研究

Engineering Application Research on Top-Cover Bolt Load Intelligent Online Monitoring System based on Optical Fiber Technology

水轮发电机组顶盖为机组重要的承载部件之一,顶盖螺栓长期受轴向水推力、转轮上腔水压脉动等交变载荷,螺栓连接的可靠性和安全性对整个机组的正常运行有着至关重要的作用。本文提出了一种基于光纤光栅传感的顶盖螺栓载荷智能监测系统,介绍了传感器设计原理、传感器结构和监测系统设计,应用该系统测量了抽水蓄能电站顶盖螺栓安装时的预紧力及机组停机转抽水调相、抽水调相转抽水、抽水转停机、停机转发电、发电转停机等工况下的螺栓轴力变化。根据测量结果可得出圆周方向均布8颗螺栓同一工况下轴力变化趋势一致,但同一工况下不同位置的螺栓轴力变化量存在差别。采用螺栓载荷智能监测系统对水轮机组顶盖螺栓轴力进行实时监测,可以超前诊断预防不安全事故的发生,为数字化电厂的日常运行监督、检修改造提供技术依据。

Top cover is one of the important load bearing components in hydro generator,in long term,top cover screws are suffering the alternating loads which caused by axial water pushing force,hydraulic pulse force from upper cavity of runner,etc.The reliability and safety of bolted screws play a crucial role in the normal operation of the entire unit.The top cover bolt load intelligent online monitoring system that based on optical fiber technology,mentioned in this article,introduce the sensor design principle,sensor structure and monitoring system design.The system is applied to measure the preload force of the top cover bolts during installation period,while also the axial force or load changes during working transfer actions,such as transfer actions from shutdown to pumping&phasing,pumping&phasing to pumped storage,pumped storage to shut down,shutdown to power generation,and power generation to shut down.According to the measurement results,it can be seen that the axial force change trend of 8 bolts in the circumferential direction is consistent under the same working condition,but the bolts installation positions are different,so the axial force changes of each bolt at different positions under the same working condition are different.The bolt load intelligent monitoring system is used to monitor the bolt axial force of the top cover of the turbine unit in real time,which can diagnose and prevent the occurrence of unsafe accidents in advance,provide a technical basis for daily operational supervision,overhaul of the digital power plant.