GE Multilin G650 Manual page 230

5 SETTINGS
The Closing process using anticipative algorithm is described on the following figure:
Where:
Referenced phasor (the one with lower frequency)
V
ref
Actual voltage phasor (the one with lower frequency)
V
s
Calculated voltage phasor, depending on the set breaker closing time (anticipative algorithm)
V'
s
ϕ
360º *TCB *Δf = Calculated angle for phasor V'
Breaker Closing time defined by setting
TCB
Δf
Frequency slip (mHz) between phasors
ϕ
Angle difference set as maximum angle difference (Δϕ
1
ϕ
= Angle difference between V
2
set as maximum angle difference.
Closing permission is given when V'
If the frequency slip is high, it is possible that as soon as the window defined by two times the maximum angle difference
(ϕ ) is entered, the relay will produce a closing permission output, if it is guaranteed that the projected phasor will be within
2
the limit marked by the setting, as shown in the following figure.
GEK-113285A
V
Ref
Figure 5–18: ANTICIPATIVE ALGORITHM
The algorithm starts operating when ϕ
and V
ref s.
is over V , which means that line and busbar voltages are in phase.
s ref
1
V
V'
s
Figure 5–19: HIGH SLIP CLOSING PERMISSION SIGNAL
G650 Generator Protection & Control System
2
1
V'
V
s
s
Max Angle Difference)
set ,
2
1
Ref
V
5.5 CONTROL ELEMENTS
equals two times the angle
2
5-87
5