ABB REG316 4 Series Operating Instructions Manual page 140

ABB Switzerland Ltd
The voltage measurement automatically compensates the group
of connection of the v.t's. For example, the phase-to-phase val-
ues are calculated for Y-connected v.t's (v.t. type UTS), while the
input voltages are used directly for delta-connected v.t's (v.t.
type UTD).
Time allowed for a signal to be received
I
R
I>
U j
&
ST
j &
Receive
I
S
I>
U j
&
TR
j
&
I
T
I>
U j
&
RS
j
&
Fig. 3.5.8.3 Block diagram
Where directional functions are configured in both line terminals,
each can send a signal from its "MeasBwd" output to the "Re-
ceive" input of the function at the opposite end of the line (e.g.
via a PLC channel) when it is measuring a fault in the reverse di-
rection. This signal prevents the respective directional overcur-
rent function from tripping, because the fault cannot be in the
zone between them. The functions therefore have to allow time,
i.e. the "wait time", for the signal from the opposite line terminal
to be received. If none is received within "tWait", the circuit-
breakers are tripped at both ends.
3-102
Forwards meas. R
Reverse meas. R
Forwards meas. S
Reverse meas. S
Forwards meas. T
Reverse meas. T
td = "Delay"
t = "tWait"
REG 316*4 1MRB520049-Uen / Rev. F
³ 1
t
&
³ 1
³ 1
Start R
Forwards meas.
AUS
³ 1
td
Start S
Reverse meas.
Start T
Start