The main reason for this large oscillation is the uneven axis of the generator and turbine. Another problem is hydraulic imbalance, mechanical imbalance and magnetic field imbalance, which can also cause strong vibration of the unit. You can start from these aspects. As for how to correct the axis, it mainly involves adjusting the clearances of the thrust, upper guide, lower guide and water guide bearings.
Relative vibration (swing) is usually measured with an eddy current sensor, absolute vibration (here it should be vibration in watts) is usually measured with a speed sensor , and the oscillation is generally larger than the vibration in watts.
The possible difference between the maximum value and the peak-to-peak value is the duration. The peak-to-peak value is usually one cycle of vibration, while the maximum value usually hasseveral cycles.
The ISO2372 standard uses the RMS (vibration intensity) value of the vibration speed as the basis for measuring the vibration condition. The vibration intensity reflects the magnitude of the vibration energy, which is more scientific.