Test And Research On Exceptional Noise Of #1 Generator In Bailongtan Hydropower Plant

Bailongtan Hydropower Plant is the 7th hydropower plant of Hongshuihe river drainage area programming. The #1 generator put into production in February 16, 1996, and it's operation noise was measured by sound-level meter at that time, noise levels of three measure point didn't exceed 90 dB and satisfied the design demand, no exceptional noise existed certainly. One year after put into production, #1 generator of Bailongtan hydropower plant existed exceptional noise clearly in startup, measure showed that the noise level of bulk room of the generator rose up to 110 dB from 97 dB, the exceptional noise decreased gradually in steady running, but it's noise is still greater than other generators. On the base of operation and observation in many year, this paper gives test and research on the exceptional noise of #1 generator.Firstly, this paper discusses noise types of generator in running and those characteristic, also separation method of different noise. By the same time, some common physical measurements of noise is introduced.Secondly, contrast and test is done to the noise of generator by using computer sound card, and the frequence component of noise is analyzed. For contrast, #3 generator is tested firstly, analysis illustrates that the frequence component of noise of #3 generator is near 50 Hz and 210 Hz, the 50 Hz component is electromagnetic noise of generator obviously, and the 210 Hz component can be judged as noise of water stream by listening after filtering by a 170Hz-250Hz band-pass filter which shields those frequence component of 170Hz downwards and 250Hz upwards. The noise of #1 generator is measured and analyzed in turn, research shows that mechanical noise is smooth relatively, and the frequence of the exceptional noise concentrates on several points such as 50Hz, 100Hz and 150Hz, It can be judged that the exceptional noise is electromagnetic noise.For determining the effect of the exceptional noise to safe operation of #1 generator, every parameter of structure and running of #1 generator is tested, include rotor roundness, air gap, Ac impedance of magnetic poles, Dc resistance of stator and rotor winding, isolation resistance, especially to swing, vibration and pulsation of water pressure, and contrast them with other generators. Testing shows that all parameters satisfy safety demand except for that axis-directive vibration of stator pedestal under full load is much large and exceed the contract demand when the exceptional noise exists.Through these testing and research, there is a total understand to the exceptional noise of #1 generator, it can judged that the exceptional noise do not effect the safe operation of #1 generator and immediate heavy repair don't need, but continuous observation is necessary.