19-05-2012, 04:18 PM
Synchronization of alternator
Parallel Operation conditions
Same RMS voltage.
Same Phase sequence.
Same Phase difference.
Almost same frequency
When these conditions are met it’s only then that the parallel operation is possible.
There are two types of paralleling systems:
Sequential paralleling
In sequential paralleling, the engine/generator sets are connected to the bus in a predetermined order.
Random method
The random access method is faster than sequential paralleling but more expensive.
Synchronous operation
When the generator is synchronized, the frequency of the system will change depending on load and the average characteristics of all the generating units connected to the grid. Large changes in system frequency can cause the generator to fall out of synchronism with the system. Protective devices on the generator will operate to disconnect it automatically