An investigation into the vibrational characteristics of pumped storage power station penstocks based on prototype observations

Blade passing frequency (BPF) vibrations, stemming from rotor-stator interaction-induced pressure pulsations in pumped storage stations, propagate through the pipeline-rock mass system, causing environmental vibration and noise. To mitigate this hazard, we developed a coupled “fluid-penstock-rock mass” dynamic response model for ambient vibration assessment. The model integrates a Finite Element-Infinite Element (FEM-IFEM) coupling scheme. It employs the Method of Characteristics (MOC) to analyze fluid transient synergy within the penstock and incorporates energy dissipation at infinite boundaries. This approach efficiently computes mountain dynamic responses, avoiding the computational constraints of full-domain modeling for large-scale rock masses. Validation against field data confirmed high model fidelity, with key measurement point errors below 10 %, meeting engineering accuracy requirements. A case study shows phase control effectively modulates vibration wave superposition: units operating with a 180° phase difference reduced peak surface acceleration by 20.4 % (1 × BPF) and 13.9 % (2 × BPF). When rock mass modulus decreased to a completely weathered state (E = 2500 MPa), vibration amplitude increased by 9.2 % and 8.1 % relative to slightly weathered (E = 55,000 MPa) and highly weathered (E = 15,000 MPa) states. These results demonstrate how geological conditions critically govern wave energy attenuation. • Operational data were acquired through in-situ monitoring and applied to analysis. • A numerical model was established using FEM-IFEM and validated against test data. • Analyzed the influence of phase difference on vibration. • Investigated the effect of rock weathering on vibration.