The relationship between grounding at one point of the hydrogenerator rotor and excessive current in

There is a direct relationship.

Under normal circumstances, the generation of current in the shaft is caused by the unequal potential at the upper and lower ends of the rotor. This is unavoidable because it is impossible to completely balance the upper and lower ends of the armature. magnetic field, but if the upper insulation of the bearing is intact, there will be no bearing current.

But if the rotor is grounded, the excitation current will flow directly into the ground through the large shaft, and this current will be detected by the shaft current transformer.