Synchronization of alternators.

Experiment No.: – 06

Name of the Experiment: –

Synchronization of alternators.

Apparatus Required: –

Sl. No.	Name	Specifications	Quantity
1	DC Motor- Alternator Set		2 nos.
2	Voltmeter	(0-500)V, MI	2 nos.
3	Rheostat	(0-80)Ω, 5A	2 nos.
4	Tachometer	Digital Type	1 no.
5	Synchronization Panel		1 no.

Circuit Diagram: –

Theory: –

A large generating station normally consists of Several AC generators to supply the load on the station. During light load on station only a few generators are also to be operated to run in the parallel with the existing generator, in order to cope up with the increased Load on the generating station.
Synchronizing of ac generator is the process of switching on an incoming alternator to the bus bar, So that it can operate in parallel with the other alternators are already connected to the bus bar. share the Load station. on the generating stations.

Conditions to be full filled:
1. Equalizing the incoming alternator Voltage to the bus bar Voltage which are indicated by a Voltmeter.
2. The Phase Sequence of the generated Voltage of incoming alternator is the same as the bus bar Voltage
3. The frequency of the generated voltage of incoming alternator is the same as bus bar frequency.

Synchrono-Scope:

It a device by which we can correctly detect the frequency with respect to bus bar.

It is fed by generated phase voltage of incoming alternator of one side and bus bar phase Voltage 00 other side.
Bright Lamp method :
One set of lamp is directly connected between the similar phases of incoming alternator and bus bar, where as other two sets of lamps the are connected crassly between phases of Incoming alternator and bus bar, So that at the instant of synchronizing which is directly one set of Lamp connected would be dark, while the other two are equally bright. If the frequencies of the alternator and the bus bar are not equal. the lamps will flicker when there is the alternations in brightness being rapid, a large difference in frequencies, & slow when the frequencies are nearly equal.

Procedures: –

1. Connections are made as per circuit diagram.
2. Ensure that the synchronizing switch is open, external resistance in the field circuit of the motor is zero and external resistance in the field circuit of alternator is maximum.
3. Switch on the dc supply to the dc motor and start it using the starter.
4. Adjust the speed of the dc motor to rated speed of alternator, by varying the rheostat in its field circuit.
5. Switch on the dc supply to the field of alternator and adjust the field current, so that the generated voltage of the alternator is equal to the bus bar voltage.
6. Switch on bus bar voltage. Now the three set of lamps will flicker.
7. Observe the phase sequence of the alternator is the same as that of the bus bar.
8. Watch for the correct instant of synchronization, with the Synchronous Switch.
9. Take the readings of parameters as per observation table.
10. Switch off the Synchronous Switch, bus bar Switch and then the dc motor to stop the de motor alternator.

Observation Table: –

Sl. No.	Parameters	Alternator_1	Alternator_2
1	Line Voltage(RY) in Volts.
2	Line Voltage(YB) in Volts.
3	Line Voltage(BR) in Volts.
4	Frequency (f) in Hz.
5	Current (A) in Amps.
6	Phase Sequence
7	Circulating Current (IR)
8	Circulating Current (IY)
9	Circulating Current (IB)

Precaution: –

1. Be sure the ground connections are common.
2. Be sure that the supply voltages are correct.
3. Be sure that the equipment is set up correctly and we are measuring the correct parameter.

Conclusion: –

To be written by student.