In order to study the influence of loading rate on the damage evolution of hydraulic concrete, notched cubic specimens with side lengths of 300 mm and 450 mm were tested by wedge splitting test with different loading rates of 0.1 mm/s, 0.01 mm/s, 0.001 mm/s. Acoustic emission technology was used to monitor the acoustic emission signals of concrete in the damage process. Test results show that the variation of AE event rate during failure process of concrete can be divided into quiet, active, and attenuation period, among these the active period increases with the decrease of loading rate. The damage was defined according to the AE events, and it is found that the damage process of hydraulic concrete can be divided into three stages: crack initiation, acceleration and failure. The smaller the loading rate is, the faster the growth rate of the acceleration stage is. The damage evolution model based on the AE event obeys Weibull distribution, which can better reflect the influence of loading rates on the damage evolution of hydraulic concrete.

In order to study the damage behavior of fiber reinforced concrete at high temperature, the acoustic characteristics of hybrid fiber reinforced concrete (PVA fiber and basalt fiber) at different temperatures were tested, and the mechanism was explained from the microscopic level by combining the results of the SEM. The results show that with the rising of temperature, the degree of ultrasonic waveform distortion is more significant, and the attenuation of waveform amplitude is gradually intensified; The incorporation of fiber or the increase of temperature will reduce the amplitude of the dominant frequency of the waveform and increase the energy dissipation caused by the ultrasonic penetration of the specimen. At high temperature, after PVA fiber is melted, a large number of pores remain and gradually form connecting pores, which promote the release of pore steam pressure and alleviate high-temperature damage, while basalt fiber continues to play a bridging effect to inhibit the continuous development of high-temperature cracks.

Pump device is the core of pump station, it is very important to carry out optimization research of pump unit. Taking the uniformity of axial velocity and the weighted average angle of velocity as optimization objectives, the hydraulic performance of inlet and outlet channels of a large vertical axial flow pump under pump mode and reverse power generation mode was optimized under all working conditions. Through the multi-scheme modeling of the inlet and outlet flow channels of the vertical axial flow pump device, the size of each section and the outer inverted line of the elbow section of the inlet and outlet flow channels were changed without changing the initial surface and the shape of the outlet section. The numerical simulation results of different inlet and outlet flow channels were compared. The distribution uniformity of flow velocity at inlet and outlet section of impeller, the average angle of weighted velocity, the hydraulic loss at inlet and outlet channel, and the variation rule of external characteristics and performance of axial flow pump device were analyzed in detail under pump mode and reverse power generation mode. The research results show that the hydraulic design of the flow channel under pump condition and reverse power generation condition can be considered comprehensively to improve the hydraulic performance of the pump unit under various operating modes in the design stage of the pump device for pump station. The research results provide theoretical support and engineering practice reference for hydraulic design and optimization of pump device in pump station.

In order to qualitatively and quantitatively grasp the influence of the installation elevation of horizontal water stops at transverse joints on the structural stress of the bulb tubular power house, taking a certain engineering project as an example, a three-dimensional finite element model of the powerhouse was established to analyze the stress of the structure on the condition of the horizontal water stops changing within a certain range. The results show that the installation height of horizontal waterstops has a significant impact on the stress of structure, and an appropriate installation height of horizontal waterstops can improve stress of structure. Taking into account various factors, the optimal horizontal water stop installation height is 70% of the installable height, which can provide a reference for the design of the transverse joint water stop of the bulb tubular power house.

Due to the long-term operation in the low-load area, the hydropower unit deviates from the optimal operation area, resulting in large vibration of the unit, poor flow state of water flow, and other adverse consequences, such as cracks in runner blades and serious cavitation of the unit. In view of the complex flow conditions in the draft tube, this paper proposes two improvement schemes. Based on RANS equation, the standard SST κ-ω turbulence model is adopted to calculate the steady and unsteady solutions for three operating conditions of 0.45P_r(P_r is rated output), 0.60P_r, and 0.75P_r. The results show that the installation of the guiding device can effectively reduce the eccentric vortex band of the draft tube, and greatly reduce the pressure pulsation amplitude, so as to reduce the vibration of the unit. Considering the streamline of draft tube, vortex zone of draft pipe, turbine efficiency and pressure pulsation amplitude, especially the importance of pressure pulsation intensity to the stable operation of the turbine, it is concluded that the symmetrical arrangement of two diversion plates at the inlet of the draft tube has the better improvement effect on the Francis turbine. The results provide a certain theoretical basis for the safe operation of the hydraulic turbine unit under low load.

At present, in the region of China Southern Power Grid, there is a case that the actual load adjustment amount of primary frequency control of some hydropower units cannot reach the theoretical value under certain working conditions, resulting in the assessment of primary frequency regulation. This paper processed the original operation data of a unit, and calculated the actual load adjustment amount and actual adjustment rate of primary frequency regulation. Compared with the theoretical value, the qualified working condition area of the primary frequency regulation process was found out. The characteristic operating points were selected in the qualified working condition area, and the multi-objective particle swarm optimization algorithm based on Pareto optimization criterion was used to find the optimal PID parameters. The simulation results show that the optimized PID parameters can make the unit have better primary frequency regulation performance index than the actual parameters of the governor.

The performance of thrust bearing is very important to the energy conversion efficiency and stable operation of hydro-generator unit. Therefore, the thrust bearing of a hydropower station was taken as the research object. The characteristics of thrust bearing oil film under different rotating speed conditions were studied. The pressure, speed and temperature distribution inside the oil film were analyzed. The influence law of rotating speed on the performance of thrust bearing was clarified. The results show that the rotational speed cannot change the pressure distribution on the thrust pad surface, but with the increase of rotational speed, the relationship between the maximum pressure and rotational speed is almost linear; The high temperature zone on the thrust pad surface moves away from the main shaft towards the oil outlet side with the increase of the rotating speed, and the average temperature difference and the maximum temperature difference show an upward trend. At runaway speed, the thrust bearing needs to bear much higher pressure than the rated speed, and also needs to bear local high temperature. The maximum temperature difference at runaway speed is more than 40 K, which is easy to cause bearing bush burning. The research results provide theoretical support for the operation and optimal design of thrust bearings in hydropower stations.

In view of the problem of inconsistency and lack of real-time synchronization of data in each security zone with the increase of specialty system, this paper analyzed the cross-regional synchronization requirements of the Yalong River integrated hydropower management and control platform system, and proposed a simple, stable and reliable cross-regional synchronization system architecture based on the characteristics of unified construction and deployment of all specialty system based on the integrated platform. Real-time synchronization was achieved by intercepting the write operation context through the platform service gateway. The design realized the unified communication management and synchronization optimization of the professional data of the Yalong River integrated control platform system, effectively improved the performance and reliability of the system, and adapted to the future development of integrated system business of water, electric power and new energy dispatch.

Long distance and concealment of underground cable in hydropower station result in difficulties in cable fault location. Due to the simple wiring, the impulse high-voltage flashover method is commonly used to locate cable faults, which needs technicians with rich waveform analysis experience to locate fault accurately. For the above situation, by studying the fault positioning principle and waveform analysis method of impact high voltage flashover, a cable fault location technology based on traveling wave cross-correlation method was proposed. The simulation analysis results show that the proposed method can effectively realize automatic cable fault location. Finally, the analysis steps and procedures of power cable fault location has been practiced in Houziyan Power Generation in Dadu River and realized high-precision positioning of 10 kV cable fault point, which reduced the cable fault locating workload and working hours while improving the efficiency of cable fault location.

At present, the existing speed relays on the market only collect single signal source, poor anti-interference. It is easy to disorder the signal of the speed node output caused by measurement signal distortion and measuring channel fault. In order to improve the reliability and accuracy of the speed relay, two channels of residual voltage signals and two channels of sprocket speed measurement signals were respectively connected. Then the dual-probe tooth sequential speed measurement method was combined with the logic of selecting one out of three speed signals. The judgment method selected one speed signal as the main signal. In the signal output process of the rotational speed node, the limiting average filtering method and the method of retrieval interference output blocking were applied to eliminate the distortion in the signal output process. Through the simulation test bench test and the application in the actual generator set, the anti-interference ability of the acquisition signal loop, the signal measurement accuracy, and the reliability of the output action of the speed node have been significantly improved.