| Vibration is a common phenomenon in life, and is more common in rotating machinery. Turbine is a kind of rotating machinery, the vibration is variousin, and the mechanism which produce vibration is complex and variable. The vibration of t urbine not only can cause damage itself and lead to a major accident, also affect the stability of power system, even cause harm to personnel. Therefore,it have a positive significance to monitor and research the vibration of hydro-generator units. At present,the development of small hydropower is getting better and better; however, due to investment less, vibration monitoring is very lack, so fault is not found in time.In this article, Unit 2 and Unit 3 units are the test object in Xida hydropower station, two units are all small-scale Francis hydroelectric generating set, rated power is 500 KW. Unit 2 has stop working for repairing, and unit 3 is in the running state daily. 11 working conditions were set up in two units, 6 groups of sensors were set to respectively monitor the shaft swing of flange and water guide bearing and the vibration of the situation in the upper frame, the lower guide bearing, water-guide bearing, roof under various operating conditions. In this experiment, the DASP- V10 vibration analysis software was used to analyse the data, the data of unit 2 and 3 were compared, at the same time compared with the national standard, to make analysis and evaluation. The causes of vibration are explored based on related theory to diagnose the fault.The data of unit 2 and unit 3 were used to do time-domain analysis,frequency-domain analysis and shaft centerline orbit. Results showed that the factors cause vibration of units 2 and unit 3 are mechanical, hydraulic, and electromagnetic.In unit 2, the degree of shaft swing is overweight and the vibration amplitude is larger in each parts, the reason is that the axis is not straight. Although unit 3 is run, there are also some vibration problems to need to improve. The analysis results can provides technical guidance for the maintenance and overhaul of the unit. |
