Siemens siprotec 7SD5 User Manual page 48

2 Functions
Figure 2-3
• Connection of the U
• If the input U
Current Connection The device features four current measurement inputs, three of which are connected
to the set of current transformers. Various possibilities exist for the fourth current input
I
• Connection of the I
• Connection of the I
48
Busbar voltage measured via transformer
input to any other voltage signal U
4
by the overvoltage protection function:
Address 210 is then set to: U4 transformer = Ux transformer.
is not required, set:
4
Address 210 U4 transformer = Not connected.
Also in this case the factor Uph / Udelta (address 211, see above) is of impor-
tance, as it is utilised for the scaling of the measurement and disturbance recording
data.
:
4
input to the earth current in the starpoint of the set of current
4
transformers on the protected feeder (normal connection):
Address 220 is then set to: I4 transformer = In prot. line and address
221 I4/Iph CT = 1.
input to a separate earth current transformer on the protected
4
feeder (e.g. a summation CT or core balance CT):
Address 220 is then set to: I4 transformer = In prot. line and address
221 I4/Iph CT is set:
This is independent of whether the device has a normal measuring current input for
I or a sensitive measuring current input (if necessary with I
4
fault protection).
, which can be processed
X
transformer for earth
E
7SD5 Manual
C53000-G1176-C169-1