Siemens 7SG11 Manual page 114

Balanced Earth-fault
Figure 3.5-1
Composite overcurrent and REF protection can be provided using a multi-element relay as Figure 3.5-3.
Figure 3.5-3
©2013 Siemens Protection Devices Limited
Balanced and Restricted Earth-fault protection of Transformers
relay circuit
non-linear
resistor
Figure 3.5-2 Restricted Earth-fault Secondary Circuit
series
stabilising
resistor
non-linear resistor
Composite Overcurrent and Restricted Earth-fault Protection
7SG11 Argus Technical Reference
Restricted Earth-fault
series stabilising
resistor
Argus REF
element
P300012 REF / Secondary
45 46
overcurrent
49 50
elements
53 54
REF
25 26
element
P300012 REF / Primary
P300012 REF / Primary
P20007 Page 59 of 71