13-02-2017, 11:18 AM
Synchronisation of the alternator means connecting an alternator on the grid in parallel with many other alternators, which is in a constant system of constant voltage and constant frequency. Many alternators and loads are connected in a grid, and all alternators in grid have the same output voltage and frequency (whatever the power). It is also said that the alternator is connected to infinite bus bar.
A stationary alternator never connects to live bus-bars, as it will result in a short-circuit in the stater winding (since there is not yet a generated emf).
Before connecting an alternator to the mains, the following conditions must be met:
Equal Voltage: The voltage of the terminal of the incoming alternator must be equal to the voltage of the bus-bar.
Similar frequency: The frequency of the generated voltage must be equal to the frequency of the voltage of the bus bar.
Phase Sequence: The sequence of phases of the three phases of the alternator should be similar to that of the grid or bus bars.
Phase Angle: The phase angle between the generated voltage and the mains voltage must be zero.
The first condition of equal voltage can be satisfied by a voltmeter. To satisfy the conditions of equal frequency and identical phases, one of the following two methods can be used:
(I) Synchronisation with incandescent lamp
Ii) Synchronisation by synchroscope.
1- The two systems must have the same voltage, and the alternator voltage can be controlled by excitation to meet this condition.
2- The frequency must be the same and this can be achieved by controlling the speed of the primary motor.
3- The two systems must have the same sequence of phases.
4- The two systems must have a zero phase difference.
So, let me assume you manged to achieve the first three conditions. Now I have an alternator that rotates with a speed and a frequency equal to the grid but there is a phase difference between them.
A stationary alternator never connects to live bus-bars, as it will result in a short-circuit in the stater winding (since there is not yet a generated emf).
Before connecting an alternator to the mains, the following conditions must be met:
Equal Voltage: The voltage of the terminal of the incoming alternator must be equal to the voltage of the bus-bar.
Similar frequency: The frequency of the generated voltage must be equal to the frequency of the voltage of the bus bar.
Phase Sequence: The sequence of phases of the three phases of the alternator should be similar to that of the grid or bus bars.
Phase Angle: The phase angle between the generated voltage and the mains voltage must be zero.
The first condition of equal voltage can be satisfied by a voltmeter. To satisfy the conditions of equal frequency and identical phases, one of the following two methods can be used:
(I) Synchronisation with incandescent lamp
Ii) Synchronisation by synchroscope.
1- The two systems must have the same voltage, and the alternator voltage can be controlled by excitation to meet this condition.
2- The frequency must be the same and this can be achieved by controlling the speed of the primary motor.
3- The two systems must have the same sequence of phases.
4- The two systems must have a zero phase difference.
So, let me assume you manged to achieve the first three conditions. Now I have an alternator that rotates with a speed and a frequency equal to the grid but there is a phase difference between them.