Key Technology Study On Condition-based Maintenance Of Hydraulic Machinery

With the flexibility of the output adjustment, hydropower plants play a more important role in the electrical networks. It is significant to improve the competition of hydraulic power in the development of electrical markets. And the unbalanced distribution of water resource in districts and cities water supply needs a lot of great reliable pump station. It is the trends to make condition-based maintenance and develop the technology of the faults diagnosis. This paper aims at the stability and faults diagnosis of hydraulic turbine units and pump station. Through analyzing the data measured from prototype units and model test and simulation results, some appraise are given on the units operation condition and some advice are made to improve the operating stability.The units' vibration, noise and pressure fluctuation in the draft tube are measured in Wanjiazhai hydro power station. Eighteen measuring points were arranged on the 2# and 5# units respectively. Measuring was carried out under three different heads. There were about ten output conditions for each head. The vibration under various velocities and the effect of injecting air on 5# units are measured. The efficiency, the runner and axis mode, the water leakage of guide vanes are also tested and used in the paper.Firstly, after analyzing the measured data, based on the design and standard claim, and taking into account of the practical operation, a conclusion on the safe and stable operation zone is drawn. Secondly, the power density spectrum is calculated from FFT and the units' behavior is analyzed in the frequency domain; the waterfall form for the start up process is plotted. Thirdly, the correlative coefficient is computed between the pressure fluctuation signal of draft tube and the displacement signal of upper guide bearing, the thrust bearing and the head cover, with this the conclusions on the shafts response due to pressure surge inthe draft tube is drawn. Fourthly, comparing prototype measurement with the model test, the pressure pulsation in the draft tube is analyzed. At last, with the numerical simulation results of three-dimensional viscous flowing analysis and modal analysis, the safe and stable operation zone is plotted out, which provides some directions on the operation.The numerical simulation of inner flow, the measurement of velocity distributing and the pressure fluctuation performance are done on the 15°slantwise pump used in Taipuhe River pump station. The behavior of hydraulic force and inner flow field is studied, which will provide some practical advices on the flow path design and bearings choice. The key of condition-based maintenance is faults diagnosis. It is the basic work to hold a test for each component of units and make some numerical simulations. In this paper, the measured data are analyzed; in addition, the numerical simulation of the inner flow is also included. The work on faults diagnosis such as operation-zone-figure and power density spectrum develop the key technology of hydraulic machinery condition-based maintenance, on the other hand, many valuable data are accumulated for the station. All of these works will be very important to activate the condition-based maintenance of Wanjiazhai hydro-power station and Taipuhe River pump station.