Toshiba GR200 Series - (ii) Coordination between the main and the backup protections; (iii) Types of the backup protections

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 5 -
Busbar G
Zone1 in ZS
(N)
M
N
Busbar H
K
Line
Busbar R
OC
(N)
≥
Main (primary)
Zone2 in ZS
(N)
Relay
(N)
Backup (local)
Backup (remote)
EF
(N)
Trip command
&
DIF
(N)
Zone2
(N)
Fail safe (FS) relay
(N)
Extra FS relay
t
0
t
0
Delay timer
t
0
t
0
Relay
(M)
Zone1 in ZS
(M)
OC
(M)
EF
(M)
Zone2 in ZS
(M)
Fail safe (FS)
(M)
O
Relay
(O)
Zone1 in ZS
(O)
OC
(O)
EF
(O)
Zone2 in ZS
(O)
Fail safe (FS)
(O)
Extra FS
(M)
t
0
DIF
(N)
DIF
(O)
Zone1
(N)
Relay
(M)
Relay
(K)
Tele communication
TRC
Figure 1.1-3 Protection zones provided by the main relay and backup relays
†Note: When the carrier command protection function (DISCAR or DEFCAR) is
available, the function can also service as a local backup protection. We shall also
note that the function cannot operate in the device failure in the
telecommunication.
(ii) Coordination between the main and the backup protections
The operation of the backup protection is realized by retarding the operation of the backup
protection rather than the main protection; retarding is made with setting the delay timer of
the backup protection. We shall note that the setting value for the delay timer should be chosen
so that the coordination between the main protection and the backup protection is realized.
The degree for retarding the backup protection is determined by the consideration of operating
and reset time margins:
• Operating time of the main protection
• Reset time of backup protections
• Operating time of the circuit breaker
(iii) Types of the backup protections
The backup protections are grouped into two: 1.backup protections serviced from the remote
end far from the location of the main protection and 2.backup protections serviced locally as
same as the main protection.