Hydraulic-mechanical coupling vibration performance of pumped storage power station with two turbine units sharing one tunnel

Guo, Wencheng; Wu, Fulin

doi:10.1016/j.est.2022.105082

Cited by 17 publications

(7 citation statements)

References 28 publications

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“…They include cogging, reluctance, and commutation torques, and are proportional to the rotational speed of the machine [15]. They are lumped in (4c) and shown in (6).…”

Section: ) Construction-induced Torque Componentsmentioning

confidence: 99%

Variable Frequency Drives-Induced Torsional Stresses in Pumped Hydropower Storage Applications

Lingom,

Song-Manguelle,

Betoka-Onyama

et al. 2024

IEEE Access

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Despite consistent maintenance and monitoring equipment installed in pumped storage hydropower (PSH) facilities, many shafts and electrical component failures are reported, possibly resulting from undetected sources. These sources include undetectable vibrations or, in certain conditions, highfrequency mechanical or electrical harmonics. They may induce premature material fatigue and aging, leading to accelerated wear and premature system failure. This paper presents a direct method for plotting Campbell diagrams of large motors supplied by variable frequency drives for torsional analysis purposes. The method is applied to two-level, three-level neutral-point clamped, and seven-level cascaded H-bridge multilevel inverters, commonly used industrially available voltage source inverter (VSI) topologies for pumped PSH plants. These diagrams display the locations where torsional stress components induced by VFDs can interfere with shaft resonance modes. These locations are where threatening torsional stresses can build up. The method simplifies the determination of the magnitude of stimulus forces in the motor airgap that may threaten the shaft. An analytical assessment of the cascaded H-bridge VFD-induced torsional stresses under unbalanced operation is also proposed. The accuracy of the theoretical developments is supported by selected simulations results at different operating points and different fault conditions. Hybrid experimental-numerical VFD-induced harmonic stress analysis is also performed to demonstrate the relevance of the proposed study. Results are crucial for a robust design of the system integration to avoid catastrophic failures.

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“…They include cogging, reluctance, and commutation torques, and are proportional to the rotational speed of the machine [15]. They are lumped in (4c) and shown in (6).…”

Section: ) Construction-induced Torque Componentsmentioning

confidence: 99%

Variable Frequency Drives-Induced Torsional Stresses in Pumped Hydropower Storage Applications

Lingom,

Song-Manguelle,

Betoka-Onyama

et al. 2024

IEEE Access

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“…For complex water pipeline systems, an overall matrix was established for the numerical simulation. The flow‐rate values and pressure vibration values at different locations along the underground buried pipe system were solved programmatically, and the calculated pressure pulsation values were used as the loads acting on the inner wall of the steel pipe for the ground vibration simulation 47,48 …”

Section: Finite Element Simulation Of the Dynamic Response Of The Env...mentioning

confidence: 99%

“…The flow-rate values and pressure vibration values at different locations along the underground buried pipe system were solved programmatically, and the calculated pressure pulsation values were used as the loads acting on the inner wall of the steel pipe for the ground vibration simulation. 47,48 The relationship between the oscillating complex head and complex flow rate for the first and last sections of the pipeline may be expressed using the transfer matrix method as follows 49 : The oscillating complex head and the complex flow rate of the first and last sections of each pipe in the system form a vector of unknowns X. In the study of hydraulic vibration, the mathematical model of all boundary conditions is simplified to a known impedance form.…”

Section: Calculation Of the Pressure Pulsation Loadmentioning

confidence: 99%

Study of the inhibitory effect of a soft cushion on the propagation of pressure pulsation in pumped storage power stations

Yang,

Wang,

Yang

et al. 2023

Earthquake Engineering and Resilience

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High‐frequency pressure pulsations are hydraulic phenomena that are frequently observed in pumped storage power stations. These pulsations can propagate through the steel pipes, concrete lining, and the surrounding rock system, which in turn may have detrimental effects on the environment, such as noise pollution, and relocation of the local residents. This paper proposes a vibration‐damping concept that involves wrapping a local soft cushion layer outside the buried steel pipe; this layer could partially eliminate the pressure fluctuations in the headrace tunnel, thereby reducing the ground vibrations caused by the pressure pulsations. In this study, the finite element method was used to model the propagation of vibrations in the surrounding rock and fluid‐filled pipes, including static simulation of the structure, and dynamic simulation of the surrounding rock. The simulation results suggest that adding an appropriate local soft bedding layer can effectively reduce the ground vibrations by more than 60% and the possible surface noise within the standard vertical vibration norms. The inhibitory effect of the soft cushion on the propagation of vibrations is determined by the wrapping angle, thickness, and material of the bedding layer. This effect increases with increasing wrapping angle and thickness of the bedding layer, and decreases with increasing elastic modulus of the material. After the addition of the bedding layer between the steel pipe and concrete lining, the pressure in the inner pipe is primarily borne by the steel lining rather than the coupling of the steel lining, concrete lining, and the surrounding rock. Hence, the thickness of the part of the steel liner in contact with the soft bedding layer should be increased. In addition, the thickness variations in the steel pipe joints should be smooth to avoid stress concentration.

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“…Ma et al [20] used the overall matrix method to calculate engineering examples and found that could accurately solve the stability domain of complex water transmission power generation systems. Guo et al [21] studied the vibration characteristics of the PSPS with two turbine units sharing one tunnel based on the overall matrix method and analyzed the influence of the hydraulic system and mechanical parameters on the vibration characteristics. Yan et al [22] researched that the overall matrix method can replace the stability analysis in the frequency domain of the transfer matrix method and has better applicability and flexibility.…”

Section: Introductionmentioning

confidence: 99%

Analysis of self-oscillation stability of a pump-turbine in the S-shaped regions of characteristic curves

Chen,

Lai,

Chen

et al. 2024

J. Phys.: Conf. Ser.

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The hydraulic oscillation of pumped-storage power station (PSPS) affects the safe and stable operation of the power station. The S-shaped characteristic curves of pump-turbine may sometimes result in instability in speed-no-load operation. To investigate the instability mechanisms and identify the main factors that affect stability, this paper used the overall matrix method to establish a self-excited oscillation calculation model of a PSPS and analyzed the stability characteristics and influencing factors of the S-shaped regions of the speed-no-load opening. The results show that when the slope of the characteristic curve is negative, the natural frequency attenuation factors of the system are negative, demonstrating stability. When the slope of the characteristic curve is positive, the system remains stable if the slope is large. However, if the slope of the characteristic curve is below a certain value, which may lead to instability. Increasing the inlet valve resistance and appropriately changing the valve layout position can enhance the stability of the system. The damping surge chamber fluctuations have no impact on system stability. The study also found that the stability regions of the S-shaped regions are related to the slope of the characteristic curve, the unit operating discharge, and the value resistance coefficient.

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Hydraulic-mechanical coupling vibration performance of pumped storage power station with two turbine units sharing one tunnel

Cited by 17 publications

References 28 publications

Variable Frequency Drives-Induced Torsional Stresses in Pumped Hydropower Storage Applications

Variable Frequency Drives-Induced Torsional Stresses in Pumped Hydropower Storage Applications

Study of the inhibitory effect of a soft cushion on the propagation of pressure pulsation in pumped storage power stations

Analysis of self-oscillation stability of a pump-turbine in the S-shaped regions of characteristic curves

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