Noncontact Vibrational Measurement Technology of Steam Turbine Blade

One of the important ways to increase reliability of the power plant is to measure the vibration of steam turbine blades in service operation. The measurement of the rotating blades is usually executed by strain gage, however, since the turbine has multiple stages, it is generally difficult to attach the strain gages to the rotating blades obtain signals from the gages, especially in the intermediate stages. Furthermore, gages and wirings must endure high centrifugal force of rotating blades, steam pressure, and moisture in the turbine under operation. This paper presents noncontact measurement technology Which measured the vibration of the steam turbine blades during operation using a laser beam installed in a stationary casing. Furthermore, this paper delineates technical problem in the measurement of the steam turbine blades, such as the Severe environment in which light is irregularly reflected, the durability of sensors, and small amplitude due to the shroud blade.