Sel 411L - Figure 3.193 Enable Logic for the 87 L Data Transmission and Differential Elements; Figure 3.194 Blocking Logic for the 87 L Function; Table 3.147 87 L Blocking Relay Word Bits

P.3.281
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
87L Enable and Blocking Logic
Figure 3.193 Enable Logic for the 87L Data Transmission and Differential
Elements
Figure 3.194 shows the blocking logic for the 87L function. Several
conditions drive the local blocking action that the 87BLKL Relay Word bit
signals. These include relay software and hardware alarms (HALARM Relay
Word bit), two 87L watchdog logic-asserted alarms (87ERR1 and 87ERR2
Relay Word bits (see 87L Watchdog Monitor for more details), a blocking
action from the time fallback Mode 1 logic (see 87L Time Fallback Logic),
and the user-programmable SEL
OGIC control equation, 87BLOCK.
The BLOCK bit embedded in the 87L packets distributes local block condition
for the 87L function (87BLKL) to all other relays of the 87L scheme.
If the blocking bit arrives on the required channel (87CHpRQ asserted, see
87L Active and Required Channel Logic), it drives the 87BLK Relay Word bit
in the same way as the local blocking action 87BLKL.
Consequently, the scheme automatically distributes 87L blocking action to all
relay terminals. Blocking of one terminal blocks all remote 87L elements as well.
Figure 3.194 Blocking Logic for the 87L Function
Ta b l e 3.1 47 87 L B l o c k i n g Re l ay Wo r d B i t s
Name Description
87BLK 87L function is blocked locally or remotely
87BLKL 87L function is blocked locally
Settings
Settings
E87L = Y
E87CH = N
87LPP = OFF
87LQP = OFF
87LGP = OFF
87LP Enabled
87L Data
Communications
Enabled
87LQ Enabled
87LG Enabled
All Required
Channels
87BLK
87BLKL
BLOCK Bit In
the Outgoing
87L Packets
0
250 ms
Blocking Action From the
Time Fallback Mode 1
HALARM
87ERR1
87ERR2
Relay
Word Bits
87BLOCK
87CHpRQ
BLOCK Bit Received On
the p-th Channel
E87L=N
Relay
Word Bit
Relay
Word Bit
Relay
Word Bit