Alstom MiCOM P54 Series - 1.24 Zone 1 extension and loss of load schemes (Distance option only)

P54x/EN OP/La4 Operation
(OP) 5-74 MiCOM P543, P544, P545 & P546
OP
 A current reversal guard timer is included in the signal send logic to prevent unwanted
trips of the relay on the healthy circuit, during current reversal situations on a parallel
circuit.
 To allow time for a blocking signal to arrive, a short time delay on aided tripping,
Delta dly, must be used.
This scheme is similar to that used in the LFDC relay, and is shown in Figure 49.
Send logi
c:  Fault Reverse
Trip logic:  Fault Forward, plus Channel NOT Recieved, delayed by Tp.
DIR FWD
Z (T)
DIR FWD
Z (T)
R
R
DIR REV
DIR REV
G
H
CTX
CRX
Signalling
Equipment
CTX
CRX
Signalling
Equipment
DIR REV
DIR REV
& &
DIR FWD
DIR FWD
1
1
Trip G
Trip H
END G
END H
t
t
0
0
Z
Z
TZ(T)
TZ(T)
P1233ENa
P1019ENa
Figure 49 delta directional comparison BLOCKING scheme
1.24 Zone 1 extension and loss of load schemes (Distance option only)
The Mi
COM P54x offers additional non-channel distance schemes, notably Zone 1
extension, and loss of load.