User Manual Chapter 1
GFK-2749A Jan 2020
PSM Module Description and Specifications 14
Fast Rotating Phase Angles
For faster rotating phase angles where Angle Delay > (Phase_Shift_Thr - 2º)/2, these
equations apply:
PhaseShiftOK = On @ Angle Delay
PhaseShiftOK = Off @ Angle Delay – Phase_Shift_Thr
Figure 6 Fast Rotation: Angle Delay > (Phase_Shift_Thr - 2º)/2
If a request to sync is on or received by the PSM module at any time in the green region
(while PhaseShiftOK = on), the CloseRelayOK status bit will be set and the IC694ACC200
output contacts will close.
Once CloseRelayOK is on and the IC694ACC200 output contacts are closed, they remain on
and closed through the green, orange and yellow regions, regardless of grid alarms, until
after the breaker delay plus 24 power line cycles pass, to allow the newly synchronized grids
to settle. After the settling time, all ANSI protections are reinstated and the PSM monitors
the Delta Frequency, Delta Voltage and Phase Shift status bits again. In the absence of other
alarms, the phase angle is allowed to drift within the phase shift threshold (the yellow
region) indefinitely as the PSM waits for the physical contacts to synchronize the grids.
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
Δ
F (slip frequency) = 0.09Hz
Angle Delay = (360º x 0.09Hz x 0.800sec) = 25.9º
PhaseShiftOK = On @ 25.9º {Angle Delay}
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