6 MJ-4A & MJ-4B Control Panel Automatic Mode
50 Siemens Energy, Inc.
6.5.4 Power Flow Modes
The MJ-4
supports six Power Flow Modes: Forward
Locked, Reverse Locked, Bidirectional, Neutral Reverse,
Idle Reverse, and Co-generation. Your selection of one of
these determines which algorithm the control program
uses under reverse power flow conditions.
* If tap position is not known, Neut R operates same as Idle R.
*For Co-gen mode when in Reverse Power Flow mode,
use Forward Voltage, BW, and Time Delay setpoints, but
use Reverse Line Drop Compensation values.
Table 6.3 Tap Changer Direction
Power Flow Mode
Line Drop
Compensation
Values
Power Flow Direction
Forward Reverse
MJ-4
Internal Operation
Forward Reverse
Tap Change Control
See Table 6.4
Bi-Dir F
••
Forward
R
••
Reverse
Neut R F
••
Forward
••
Return to Neutral*
Idle R F
••
Forward
••
None (tap idles)
Co-Gen F
••
Forward
R (See Table 6.4)
••
Forward
F Lock F
••
Forward
F
••
Forward
R Lock R
••
Reverse
R
••
Reverse
Table 6.4 Tap Change Control Operation
Forward Reverse
“Vcomp” location “L” Bushing “S” Bushing
Out of Band High Lower Raise
Out of Band Low Raise Lower
Voltage Setpoint Fwd Volts Rev Volts
Bandwidth Setpoint Fwd BW Rev BW
Time Delay Setpoint Fwd Delay Rev Delay
Line Drop Compensation
(R = Resistance, X = Reactance)
F*
Fwd Comp (R)
Fwd Comp(X)
R*
Rev Comp (R)
Rev Comp (X)