Alstom MiCOM P546 - 1.23.1 Distance scheme PUR - permissive underreach transfer trip (Distance option only)

Operation P54x/EN OP/La4
MiCOM P543, P544, P545 & P546 (OP) 5-61
OP
P1583ENb
DDB: DEF FWD (996)
SET: Aided DEF Enable
SET: Aided Distance En
DDB: Ph Select B (1011)
DDB: Aided Distance Trip Inhibit (394, 397)
1
1
1
1
1
&
&
&
&
1
&
&
&
&
&
&
&
tDST
&
&
&
&
DDB: Aided Trip En (501, 517)
DDB: Custom Aided Trip En (502, 518)
DDB: Z2 AN (966)
DDB: Z2 BN
(967)
DDB: Z2 CN
(968)
Distance
Enable
DDB: Z2 AB
(969)
DDB: Z2 BC
(970)
DDB: Z2 CA (971)
DDB: Aided Distance Trip (503, 519)
&
&
&
&
1
&
&
&
&
tDEF
&
DDB: Ph Select A (1010)
DDB: Ph Select C (1012)
DDB: Aided DEF Trip Inhibit (395, 398)
DDB: Ph Select N (1013)
SET: 3 Pole DEF Tripping
DDB: Aided DEF Trip (505, 521)
1
1
1
1
1
1
DDB: Aided Trip N
(636, 646)
DDB: Aided Trip C
(635, 645)
DDB: Aided Trip B
(634, 644)
DDB: Aided Trip A
(633, 643)
DDB: Aided DEF 3 Pole Trip
(641, 651)
Aided DEF Trip A
Aided DEF Trip B
Aided DEF Trip C
Aided DEF Trip N
Aided Distance Trip A
Aided Distance Trip B
Aided Distance Trip C
Aided Distance Trip N
Figure 35 Aided tripping logic
1.23.1 Distance scheme PUR - permissive underrea
ch transfer trip (Distance option only)
To provide fast fault clearance for all faults, both transient and permanent, along the length
of the protected circuit, it is necessary to use a signal aided tripping scheme. The simplest
of these is the permissive underreach protection scheme (PUR). The channel for a PUR
scheme is keyed by operation of the underreaching zone 1 elements of the relay. If the
remote relay has detected a forward fault upon receipt of this signal, the relay will operate
with no additional delay. Faults in the last 20% (Note 1) of the protected line are therefore
cleared with no intentional time delay.
Note 1: Assuming a 20% typical “end-zone” when Zone 1 is set to 80% of the
protected line.
Listed below are some of the main features/requirements for a permissive underreaching
scheme:
 Only a simplex signaling channel is required
 The scheme has a high degree of security since the signaling channel is only keyed for
faults within the protected line
 If the remote terminal of a line is open then faults in the remote 20% of the line will be
cleared via the zone 2 time delay of the local relay
 If there is a weak or zero infeed from the remote line end, (i.e. current below the relay
sensitivity), then faults in the remote 20% of the line will be cleared via the zone 2 time
delay of the local relay
 If the signaling channel fails, Basic distance scheme tripping will be available