Study On Torsional Oscillation Measurement Of Turbin-Generator Units Based On CCD Technology

With the development of the electric power industry, the capacitance of a turbo-generator has increasingly become larger, which risk the torsional oscillation in the flexible shaft system of large turbine-generators. The problem of shaft torsional oscillation has become the key technology need to be solved urgently in the development of large power system and unit. The main research is how to control and long term monitor the shaft torsional oscillation. The measurement technique of torsional oscillation is an important link of torsional oscillation control and monitor system and a basement to carry out the corresponding method. It also provides foundation of shaft design.Magnetoelectricity gear method is a general torsional oscillation measurement method. It has disadvantages on less measure point and improved-needed dynamic characteristic. In the paper a new method of measuring torsional oscillation of the turbine-generator shaft was proposed on the basis of high speed CCD(Charge Coupled Device) photography.CCD torsional oscillation measurement method is based on image technology. By taking photo of shaft by CCD camera, acquire the image signal, and then extract the torsional oscillation information from it using data processing arithmetic. To analyze the feasibility of this method, a principle experiment was carried out. The equipment, content and conclusion of the experiment were detailed in this paper.The design of image fountain signal, imaging technique and data processing are three key technologies to carry out CCD torsional oscillation measurement method. By analyzing the design principle, the paper devised an image source signal alternated with black and white strip and it has a good effect. Meanwhile, the system demand of imaging link was analyzed, such as light source, lens and camera etc. In addition, the principles of both the correlation algorithm and generalized correlation time delay estimation based on adaptive technology were studied, and a comparison between them was made as well.At last, an application system was designed for CCD torsional oscillation measurement method.