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:
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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. |
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| usually does not modify the value of the flux |
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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. |
- Stator
- Rotor
- Auxilliaries
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| 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). |
- open-circuit characteristic,
- short-circuit characteristic,
- saturation characteristic,
- voltage-current characteristic,
- V-curve characteristic.
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