Siemens SIPROTEC 7UT613 series Manual page 61

7UT613/63x Manual
C53000-G1176-C160-2
• 1st case: It is essential to assign the 1-phase input to that side of the main protected
object whose incoming phase currents are to be compared with the earth fault cur-
rent. Make sure that you assign the 1-phase input to the correct side. In case of
transformers, this can only be a side with an earthed starpoint (directly or via a
neutral earthing transformer in the protected zone).
In the example shown in Figure 2-2, the auxiliary measuring location X3 must be
assigned to side S1. Once the device has been "informed" of this assignment, the
current measured at current input IX3 will be reliably interpreted as the current
flowing to the starpoint of the high-voltage winding (side 1).
in the example shown in Figure 2-6 the additional measuring location X3 must be
assigned to the common winding. This winding, however, has 2 sides with 2 three-
phase measuring locations. X3 is assigned to side S1. Since the device has been
informed in address 105 PROT. OBJECT = Autotransf. that the protected object
is an auto-transformer, and via the assignment of sides 1 and 2 that these belong
to the common winding, it is obvious that X3 belongs to the common winding, and
that it is therefore assigned to sidesS1 and S2. The result is the same if X3 is as-
signed to side S2. For the auto-transformer, it is therefore irrelevant which voltage
side of the common winding (start of winding or any tap) the starpoint current is as-
signed to.
• 2nd case: For this case, the same considerations apply as for the 1st case. In the
case of generators, motors or shunt reactors, select the terminal side. You can also
use in the 2nd case a measuring location that is not assigned to the main protected
object. In the example shown in Figure 2-3, you can use the restricted earth fault
protection for the neutral reactor: The auxiliary measuring location X4 is in this case
assigned to the measuring location M5. This informs the device that the measured
values of the non-assigned measuring location M5 (3-phase) must be compared
with the measured value of the additional measuring location X4 (1-phase).
in the example shown in Figure 2-6 the additional measuring location X3 must be
assigned to the common winding. This winding, however, has 2 sides with 2 three-
phase measuring locations. X3 is assigned to side S1. Since the device has been
informed in address 105 PROT. OBJECT = Autotransf. that the protected object
is an auto-transformer, and via the assignment of sides 1 and 2 that these belong
to the common winding, it is obvious that X3 belongs to the common winding, and
that it is therefore assigned to sidesS1 and S2. The result is the same if X3 is as-
signed to side S2. For the auto-transformer, it is therefore irrelevant which voltage
side of the common winding (start of winding or any tap) the starpoint current is as-
signed to.
• 3rd case: Here again, the auxiliary measuring location must be assigned to that side
whose earth fault current is to be processed. You can also use a measuring location
that is not assigned to the main protected object. Please note that this auxiliary G96
measuring location will provide not only the measured value for the earth fault over-
current protection but also circuit breaker information (current flow and manual-
close detection) from the corresponding 3-phase measuring location.
One can also proceed as described in cases 4 and 5, if the current used by the earth
fault overcurrent protection cannot be assigned to a specific side or 3-phase mea-
suring location.
2.1 General
61