Toshiba GR200 Series Instruction Manual page 35

Id
Setting[DIFCH-I]
a. DIFCH characteristic in normal
Figure 2.1-3 Transformation from the normal to the non-restrained DIFCH characteristic
Note Slope value (=0.15) are set is defined in Equation (2.1-1)
1
Note See section 2.1.11 for PLC connection point "DIFCH-CHARA".
2
Figure 2.1-4
check-zone-protection with the normal restraint characteristic will not operate if a fault occurs
in Zone B. This is because the outgoing current can be over half of the incoming current
depending upon load and fault current conditions. When two out of four DSs (representing the
two bus-sections and two bus-couplers) are opened, the normal restraint characteristic is
modified to a non-restraint characteristic. As a result, the check-zone-protection can operate
correctly.
Bus
Coupler 1
"Open"
DS signals acquired by BIs
Coupler1
Output signal
open
Section1
closed 2 out of 4
logic
Coupler2
closed
Section2
open
"2 out of 4 logic" is configured by the
PLC function.
Figure 2.1-4 Example of check-zone-protection under extraordinary operational conditions
Note: the above bus-bar arrangement is provided only by way of example in order to
3
facilitate the discussion of unusual operational circumstances.
Id=Ir
Operate
Id=[DIFCH-Slope] Ir
Ir
shows an unusual operational arrangement of bus-bar configuration; a
3
Zone C
Zone A
Bus
Load
Section 1
"Closed"
Fault
Bus
Section 2
Load
"Open"
Zone D
Zone B
Characteristic for of check-zone-protection
DIFCH-CHAR
800100EBC0
A
- 21 -
Id
Setting[DIFCH-I]
b. DIFCH characteristic modified to non-restrained characteristic
No.1 Bus
Bus
Coupler 2
"Closed"
No.2 Bus
Check Zone Protection
Id=Ir
Id
d
Operate
Setting[DIFCH-I]
Restraint characteristic
The Restraint characteristic is modified to a Non-restraint characteristic
by application of the PLC signal "DIFCH-CHARA"
6F2S1931 (0.20)
Id=Ir
Operate
Id=0.15Ir
Ir
Id
Operate
Setting[DIFCH-I]
Ir
Non-restraint characteristic
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)
Id=Ir
Ir