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Synchronous generator is an a.c. machine with its speed proportional to the frequency of the grid (network) on which it is connected, and the speed does not vary with the load.
The basic relation of a synchronous generator is:

f = p * n

The rotor winding of a hydro generator is supplied with dc. This current is provided by an excitation system. There are two types of such systems:
  • static and
  • rotating.
Paralleling means to conect a generator in parallel to the grid.

Paralleling a generator with a voltage grid without a sudden raise of current is accomplished using the synchronization method.
REACTION
REASON
CHARACTER
Transversal
resistive load
usually does not modify the value of the flux
Longitudinal
inductive load
demagnetizing
capacitive load
magnetizing
We can load/unload with active power (P) a hydro generator conected to the grid, simply by transferring to it mechanical energy, through the shaft, from the hydraulic turbine.

By modifying the field current (using the excitation system), we may modify the reactive power (Q) of the hydro generator.
  1. Stator
  2. Rotor
  3. Auxilliaries
The electromagnetic torque of a hydro generator is a braking one, in opposition with the active torque of the hydraulic turbine (the prime mover).

So, we can use an electrical braking to stop the hydro generator after we close the water access to the turbine (in which case the turbine's active torque is zero).

  1. open-circuit characteristic,
  2. short-circuit characteristic,
  3. saturation characteristic,
  4. voltage-current characteristic,
  5. V-curve characteristic.
HPG Home
Hydro Generators
Hydraulic Turbines
Related Links
About MBM
About HG
Armature Reaction
Excitation Systems
Paralleling
Loading
Design
Electrical Braking
Characteristics
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