7PG2113/4/5/6 Commissioning & Maintenance
©2012 Siemens Protection Devices Limited
Chapter 6 Page 33 of 77
2.7
Derived Earth Fault (67/50N, 67/51N)
Figure 2.7-1 Derived Earth Fault
Voltage Inputs:
V
L1
(V
A
), V
L2
(V
B
), V
L3
(V
C
)
Current Inputs:
I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
)
Disable:
37, 46, 49, 60CTS, 50CBF, 60CTS, 46BC, 79
Map Pickup LED:
51N-n/50N-n - Self Reset
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. Derived EF, Measured EF Sensitive EF & Restricted EF protections can be
Enabled/Disabled individually or as groups in the ‘Function Config’ menu.
Derived EF elements can be separated from Measured/Sensitive EF by arrangement of the secondary injection
circuit by shorting/disconnecting I
4
Input.
If any of these elements are defined as directional the correct voltage phase direction will be required to produce
an operation of those elements.