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Manual 26174
EGCP-2 Engine Generator Control Package
Woodward
131
Phase Matching Synchronizing
The phase matching synchronizing mode corrects the frequency and phase of
the generator to lock it to the bus frequency and phase. The microprocessor uses
signal processing techniques to derive the difference in phase of the generator A
and bus A phase voltage signals. When there is a difference, the synchronizer
sends a correction signal to the speed control. The correction signal from the
speed bias output increases or decreases engine speed depending on whether
the slip is faster or slower than the bus. A PI (proportional, integral) controller
provides the correction signal. Gain and Stability adjustments to the PI controller
are provided to allow stable operation of the automatic synchronizer function over
a wide range of system dynamics.
Synch-Check
The synch-check function determines when all conditions for proper
synchronization are satisfied and energizes the breaker closure relay. The
generator and bus voltage comparison is made if the voltage matching function is
enabled. The generator voltage must be within the specified voltage window
above bus voltage before the breaker closure command may be given.
To minimize transients, the breaker must be closed when the phase difference
between the generator and bus is near zero. Also, maintaining the phase angle
error between the generator and the bus within a specified Max Phase Window
for a specific Dwell Time allows the synchronizer to be configured for a wide
range of synchronizing conditions. The Max Phase Window and Dwell Time set
points are found in the Synchroscope tuning menu of the EGCP-2.
A larger Max Phase Window, and Shorter Dwell time would typically be used on
emergency standby sets, where rapid synchronization is needed. The larger
window and shorter dwell time make the synchronizer less sensitive to transitions
in generator frequency and phase angle error when compared to the bus the
generator is synchronizing to. When all conditions of voltage and phase are met,
then the breaker closure command is given.
A smaller Max Phase Window and Longer Dwell Time would be used on
generating systems where smooth and precise synchronization is required, and
the time to synchronize is not as critical as would be seen in a standby
application. A smaller window and longer dwell time require the generator to be
within closer frequency and phase angle error tolerance when compared to the
bus the generator is synchronizing to. When all conditions for voltage and phase
are met, then the breaker closure command is given.
Multiple Shot Reclosing
The multiple shot reclosing function allows multiple closing attempts. The control
provides set points for the number of
Close Attempts
and the
Reclose Delay
time. Failure to get closure after the specified number of attempts triggers the
Sync Reclose Alarm
and locks out the synchronizer by setting it to the auto-off
mode. Clearing the alarm condition, in the Alarm/Event Log, will reset the
synchronizer.