Toshiba GR200 Series Instruction Manual page 37

Busbar A
Busbar B
DS DS DS DS
11 12 11 12
CB CB
CH1
Current Current
CH1
Current input
DS11 contact
evaluation
DS12 contact
CH 2
Current input
DS11 contact
evaluation
DS12 contact
CH 3
Current input
DS11 contact
evaluation
DS12 contact
CH 24
Current input
DS11 contact
evaluation
DS12 contact
Figure 2.1-5 Determination of Current data for DIF relay computation
Under normal bus-bar configuration, the operation of a DS may turn a load current into
a false differential current for a transient period and a discriminating-zone-protection may
operate if the operation time or reset time between the DS main-contact and the DS auxiliary
contact is not coordinated. However, the user does not need to consider time coordination
between the DS main-contact and DS auxiliary-contact because the selective discriminating-
zone-protection can be used in combination with the check-zone-protection
Note: Time coordination between the DS main-contact and DS auxiliary-contact is
1
difficult in practice. Therefore, operation of the discriminating-zone-protection is
used in conjunction with the operation of a check-zone-protection.
DS DS DS
11 12 11
CB CB
CH2 CH3
Current
Current data
Protection zone
information
Zone A
Replica
Zone B
Current data
Protection zone
information
Zone A
Replica
Zone B
Current data
Protection zone
information
Zone A
Replica
Zone B
Current data
Protection zone
information
Zone A
Replica
Zone B
- 23 -
ZoneA
ZoneB
DS
12
CH 24
Current
Currents used in DIF computation
DIFCH DIFZA DIFZB
&
&
&
&
&
&
&
&
6F2S1931 (0.20)
.
1
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)