Toshiba GRT100 Series Instruction Manual page 25

Setting
The following shows the setting elements for the restricted earth fault protection and their setting
ranges.
Element Range
1REF 1ik 0.05  0.50(*)
1.00  50.00
1kct1
1.00  50.00
1kct2
1kct3 1.00  50.00
50  100%
1p2
0.50  2.00(*)
1kp
0.05  0.50(*)
2REF 2ik
1.00  50.00
2kct1
1.00  50.00
2kct2
2kct3 1.00  50.00
50  100%
2p2
0.50  2.00(*)
2kp
0.05  0.50(*)
3REF 3ik
3kct1 1.00  50.00
1.00  50.00
3kct2
1.00  50.00
3kct3
50  100%
3p2
0.50  2.00(*)
3kp
0.00  10.00s
T1REF
T2REF 0.00  10.00s
0.00  10.00s
T3REF
Scheme switch
[1REF1] to [1REF5] Off/On
[2REF1] to [2REF5] Off/On
[3REF1] to [3REF5] Off/On
[1REF] to [3REF] 1Io/2Io/3Io
(*): Multiplier of secondary rated current
(**): Default settings are dependent on the models. See Appendix H.
Setting of ik (1ik, 2ik and 3ik)
1ik, 2ik and 3ik of minimum operating current settings are set as a ratio to the line CT secondary
rated current. The minimum setting for ik is set to more than the maximum erroneous zero
sequence differential current under normal operating conditions, caused maily by CT errors. A
typical setting would be between 10% and 50%.
Step Default
0.01 0.50
0.01 1.00
0.01 1.00
0.01 1.00
1% 100%
0.01 1.00
0.01 0.50
0.01 1.00
0.01 1.00
0.01 1.00
1% 100%
0.01 1.00
0.01 0.50
0.01 1.00
0.01 1.00
0.01 1.00
1% 100%
0.01 1.00
0.01s 0.00s
0.01s 0.00s
0.01s 0.00s
(**)
(**)
(**)
1Io
 24 
6 F 2 S 0 7 8 9
Remarks
Minimum operating current
CT ratio matching
% slope of DF2
DF2 sensitivity
Minimum operating current
CT ratio matching
% slope of DF2
DF2 sensitivity
Minimum operating current
CT ratio matching
% slope of DF2
DF2 sensitivity
Delayed tripping
Enable or disable to output
tripping signal
Number of line currents input to
1REF, 2REF and 3REF elements