5-86 F650 Digital Bay Controller GE Multilin
5.5 CONTROL ELEMENTS 5 SETPOINTS
5
The Closing process using anticipative algorithm is described on the following figure:
Figure 5â21: ANTICIPATIVE ALGORITHM
Where:
V
ref
Referenced phasor (the one with lower frequency)
V
s
Actual voltage phasor (the one with lower frequency)
Vâ
s
Calculated voltage phasor, depending on the set breaker closing time (anticipative algorithm)
î 360Âș *TCB *î§f = Calculated angle for phasor Vâ
s
TCB Breaker Closing time defined by setpoint
î§f Frequency slip (mHz) between phasors
î
1
Angle difference set as maximum angle difference (î§î
set ,
Max Angle Difference)
î
2
= Angle difference between V
ref
and V
s.
The algorithm starts operating when î
2
equals two times
the angle set as maximum angle difference.
Closing permission is given when
Vâ
s
is over V
ref
, which means that line and busbar voltages are in phase.
If the frequency slip is high, it is possible that as soon as the window defined by two times the maximum angle difference
(î
2
) is entered, the relay will produce a closing permission output, if it is guaranteed that the projected phasor will be within
the limit marked by the setpoint, as shown in the following figure.
Figure 5â22: HIGH SLIP CLOSING PERMISSION SIGNAL
V
Ref
V
2
â
Ref
V
2
â