Toshiba GR200 Series Instruction Manual page 33

Current differential protection (DIF)
Check-zone-protection and Discriminating-zone-protection
2.1.1
The DIF function is provided for the overall bus-bar system (described hereafter as check-zone-
protection), as well as for each individual bus-bar zone, which is sectioned by the bus-section
and bus-coupler switches (described hereafter as discriminating-zone-protection).
The elements used for the check-zone-protection (DIFCH) and the discriminating-zone-
protection (DIFZA to DIFZF) are based on the DIF principle.
The characteristics are shown in Figure 2.1-1(a) and (b); and the respective elements for
each phase (phase-A,-B,-C of DIFCH and DIFZA to DIFZF) have percentage restraint
characteristics, respectively.
Id
Setting [DIFCH-I]
Restraining current
a. DIFCH characteristic configured by settings [DIFCH-Slope]
Figure 2.1-1 Restraint characteristics for DIFCH and DIFDZ
Note: The slope-factor (k) can be changed using settings [DIFCH-Slope] and [DIFDZ-
1
Slope] (see section 2.1.5).
Figure 2.1-1
[DIFCH-I] in DIFCH and setting [DIFDZ-I] in DIFZA to DIFZF.
─────────────────────────────────────────────────────────────────
Note: The implementation of particular features is dependent upon the selection of
hardware and the configuration of functions. Several IED models do not support certain
features. To determine whether a particular feature has been implemented within an IED,
identify the IED ordering number; and check the order number for the "G&T position" whilst
referring to the comparison table below. For more information, see Appendix: Ordering.
Table 2.1-1 Comparative table in respective ordering numbers
Sec. Feature
– DIF main features
2.1.8 CT failure detection
2.1.9 DIF current monitoring
: Applicable

Id=Ir
Operate
Id=[DIFCH-Slope]×Ir
Ir
1
and [DIFCH-I]
shows minimum operating current (minDIF-I), which can be set with setting
30 31
 
 NA
 
NA: Not applicable
Id
Setting [DIFDZ-I]
b. DIFZA to DIFZH characteristics configured by setting [DIFDZ-I] and [DIFDZ-Slope]
Ordering No. at "G&T"
32 33

 
  NA

 
- 19 -
6F2S1931 (0.20)
Id=Ir
Operate
Id=[DIFDZ-Slope]×Ir
Ir
Restraining current
34 Note

 
  
 

Centralized GRB200
(Soft: 030, 031, 032, 033, 034)
1