User Manual Chapter 1
GFK-2749A Jan 2020
PSM Module Description and Specifications 13
PhaseShiftOK = On @ Angle Delay
PhaseShiftOK = Off @ –(Angle Delay+2º)
Figure 5 Slow Rotation: Angle Delay ≤ (Phase_Shift_Thr - 2º)/2
If the 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, 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 shift 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 = 200ms
Grid 1 Frequency = 60.00Hz Grid 2 Frequency = 60.01Hz
Δ
F (slip frequency) = 0.01Hz
Angle Delay = (360º x 0.01Hz x 0.200sec) = 0.72º
PhaseShiftOK = On @ 0.72º {Angle Delay}
PhaseShiftOK = Off @ -2.72º {-(Angle Delay + 2º)}
If Sync is requested while PhaseShiftOK = On, then CloseRelayOK will be set to On
for the Angle Delay + 24 cycles. At
Δ
F = 0.01HZ and 60Hz, the PhaseShiftOK window
is 200ms (0.72
⁰
) + 400ms = 600ms.
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