Toshiba GRT100 Series Instruction Manual page 24

1REF
0.00 - 10.00s
2REF
3REF
Figure 2.4.2 Scheme Logic of Restricted Earth Fault Protection
Appendix L shows applications of the three REF elements to various types of transformers.
When protecting a two- or three-winding transformer, 1REF, 2REF and 3REF elements should
be applied to the primary (or high-voltage) winding, secondary (or medium-voltage) winding and
tertiary (or low-voltage) winding respectively. This is valid for an auto-transformer protection
but the application must refer to Appendix L.
In the application to auto-transformers, one REF element may introduce two or three line
currents and one neutral current as shown in the Appendix L. 1REF to 3REF elements recognize
the number of the line currents according to the scheme switch setting of [1REF] to [3REF].
T1REF
t 0
[1REF1]

[1REF2]

"ON"
[1REF3]

"ON"
[1REF4]

[1REF5]

Same as above
Same as above
 23 
&
"ON"
&
&
&
"ON"
&
"ON"
6 F 2 S 0 7 8 9
1REF-1
1REF-2
1REF-3
1REF-4
1REF-5
2REF-1
2REF-2
2REF-3
2REF-4
2REF-5
3REF-1
3REF-2
3REF-3
3REF-4
3REF-5