Answer / k.prakashchandra

AVR maintains the set voltage and does not regulate it.APF
mode is an option in Auto- channel in addition to AVR mode
and it is put in action after synchronization.

Answer / k.prakashchandra

After synch,AVR keeps the gen voltage constant at the set
value. If the grid voltage is more than the gen voltage, the
pf becomes leading and lagging if the grid voltage is less
than the gen voltage.Then, in AVR mode the operator has to
reset the gen voltage so that the pf is slightly lagging.In
APF mode ,the pf always remains at the set value
irrespective of variations in grid voltage.

Answer / mohammed sajid

I can't understand your language mr.prakash,just explain
what is the function of AVR before & after synchronisation
with grid.

Answer / balu

Once the generator connects with the grid the system voltage depends upon to the grid referrence.the active power varies depends on the load.so load varies mean time reactive power also variey.so avr will maintaine power factor after synchronization.

Answer / k.prakashchandra

It is possible to have the changeover from AVR to APF mode
automatically on synchronization / closing unit CB and the
vice versa, using auxiliary switch of the breaker.

Answer / k.prakashchandra

It keeps the gen voltage the same at the set value
irrespective of variation in speed , load and grid voltage
after synchronization. It is useful whenever there is grid
failure as the gen speed suddenly increases to an extent
depending on the load interrupted.Then AVR does not allow
for rise in voltage.It is also very helpful while
synchronizing as you do not have to vary the excitation
every now and then ,once you have matched the voltages.If
you desire to keep the pf constant after synch and loading
,you have to switch over to APF mode from AVR ,both being
available with Auto channel.

Answer / it might be for easy calculati

It might be for
easy
calculation:-)

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