3 Mounting and Commissioning
284
7UM61 Manual
C53000-G1176-C127-3
Figure 3-21 Directional Check with Holmgreen Connection
If in an isolated network the voltage connections for the reactive current measurement
should be kept for testing, then it should be noted that for a power flow with inductive
component in forwards direction a backwards direction results (contrary to an earth
fault in this direction).
Shut down generator after completion of the directional tests. Correct connections
must be re-established and re-checked.
Spill Cur r e nt For calibration to the spill current, a three-pole short-circuit bridge that is able to with-
stand rated current is installed at the circuit breaker. Start up generator and slowly
excite until the rated machine current is reached.
Read out the operational measured value I
EE
. This measured values determines the
setting value of address 5003 3I0>. Parameter 3I0> should be about twice that mea-
sured value to ensure a sufficient security margin between the earth fault current used
for directional determination and the spill current. Next, check whether the protection
zone determined by the setting value U0> must be reduced.
Activate the stator earth fault protection: Address 5001 S/E/F PROT. = ON.
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