Optical strain monitoring techniques for life assessment of components in power generation plants

The current paper presents the ongoing development of a combination of two methods for monitoring creep strain in mechanical components of electrical power generation plants. This is to obtain, during plant shut-down maintenance periods, needed data to assess the remaining life of installed steam pipes and other components. Related to this research, but not reported on in the current paper, is the development of monitoring for detection of the onset of fatigue and other failure processes in wind turbine generator blades. The auto-reference creep management and control (ARCMAC) system uses precision optics and a charge-coupled device (CCD) camera for uniaxial and biaxial strain measurement. Digital image correlation (DIC) is employed to obtain strain distribution data about the ARCMAC point-to-point monitored sites. These and other systems are being developed to obtain a more comprehensive range of life assessment data. This is mostly for assessing longevity of steam pipes and other components in power stations that are subject to demanding and hostile operational environments. These permanently installed monitoring systems need to be rugged to withstand the demanding heat and mechanical forces to which they are subjected and of a compact design so they can be sited in difficult-to-access locations. This is one of the advantages of the combined ARCMAC and DIC system that is further being developed. These systems are essential for cost-effective management of power plant operation and maintenance and for achieving reliable continuity of service.