ABB SYN 5201 Operating Instructions Manual page 109

Operating Instructions
If synchronization fails due to the voltage condition, it should be checked whether the
limits Umax and Umin are maintained. If the voltage regulator is switched to manual
regulation (field current regulator), the actual value, together with the generator voltage,
is also dependent on the turbine speed. It can thus be difficult to bring the voltage within
the tolerance band if the speed of the turbine varies greatly. Under certain
circumstances, the voltage matcher may have to be set differently for field current
regulator operation (different parameter set) than for voltage regulator operation.
Poor synchronization
If increased active or reactive power surges occur during synchronization, it is essential
to connect through again and check the measurement of U1 and U2 for angle and equal
voltage. Using the transient recorder of the PC tool SynView or using an external
transient recorder, it should also be checked whether the breaker was actuated in the
zero passage of the  U signal. Otherwise the breaker closing time t on must be
adjusted.
Following commissioning (operation)
In this case, setting errors can usually be ruled out. It should be considered whether any
changes were made to the plant prior to the failed synchronization which could affect the
synchronizing process.
If the synchronizing process already took a long time beforehand, it may be that a fault
message might suddenly appear due to a difference in the duration of the process.
Otherwise, poor contacts, dropped connections, malfunctioning relays or tripped fuses
may be the cause.
9.2.5 Fault rectification
Cancelling faults
Once the cause of the fault has been found and eliminated, the active error messages
can be cancelled on the SYNCHROTACT .
abb
ABB Switzerland Ltd
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SYN 5201/SYN 5202
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