GE PACSystems RX3i User Manual page 22

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Example: Angle Delay > (Phase_Shift_Thr - 2º)/2
Phase_Shift_Thr = 10º
Breaker Delay = 800ms
Grid 1 Frequency = 60.00Hz
Grid 2 Frequency = 60.09Hz
ΔF (slip frequency) = 0.09Hz
Angle Delay = (360º x 0.09Hz x 0.800sec) = 25.9º
PhaseShiftOK = On @ 25.9º {Angle Delay}
PhaseShiftOK = Off @ 15.9º {Angle Delay – Phase_Shift_Thr}
If Sync is requested while PhaseShiftOK = On, then CloseRelayOK will be set to
On for the Angle Delay + 24 cycles. At ΔF = 0.09Hz and 60Hz, the PhaseShiftOK
window is 800ms (25.9⁰) + 400ms = 1.2 seconds.
Static Phase Angle Synchronization
In static phase angle synchronization, the PSM will set PhaseShiftOK bit between
±Phase_Shift_Thr, regardless of the Delta Frequency (Slip Frequency). This mode is
selected by setting the Breaker Delay hardware configuration parameter to zero.
With no breaker delay information, the PSM reverts to classic synchronization. Either the
control system holds the phase angle within the Phase_Shift_Thr before requesting
Synchronization, or the rate of change of the phase angle and the breaker delay are
known and the control system holds the Delta Frequency (Slip Frequency) at a value
calculated to bring the contacts to closure at or near 0⁰ phase angle.
PACSystems* RX3i Power Sync and Measurement System – February 2013
0º
+Phase_Shift_Thr
-Phase_Shift_Thr
SYNCHROSCOPE
GFK-2749