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Section 10
Testing functionality by secondary injection
10.9.2.2
190
BLKU and BLKZ signals should appear simultaneously wether the BLKU and
BLKZ reset depends on the setting SealIn "on" or "off". If "on" no reset, if "off"
reset.
7.
After more than 5 seconds disconnect the remaining two-phase voltages and all
three currents.
•
There should be no change in the high status of the output signals BLKU
and BLKZ.
•
The signal 3PH will appear.
8.
Establish normal voltage and current operating conditions simultaneously and
observe the corresponding output signals.
They should change to logical 0 as follows:
•
Signal 3PH after about 25ms
•
Signal BLKU after about 50ms
•
Signal BLKZ after about 200ms
Measuring the operate value for the negative sequence function
Measure the operate value for the negative sequence function, if included in the IED.
1.
Simulate normal operating conditions with the three-phase currents in phase
with their corresponding phase voltages and with all of them equal to their rated
values.
2.
Slowly decrease the measured voltage in one phase until the BLKU signal
appears.
3.
Record the measured voltage and calculate the corresponding negative-
sequence voltage according to the equation (observe that the voltages in the
equation are phasors):
3
⋅
U
=
U
+
a
2
⋅
2
L
1
EQUATION707 V2 EN
Where:
U
, U
and U
L1
L2
L3
IEC00000275 V1 EN
p ×
2
j
= ×
= -
a
1
e
0, 5
3
IECEQUATION00022 V2 EN
4.
Compare the result with the set value of the negative-sequence operating voltage
(consider that the set value 3U2> is in percentage of the base voltage UBase).
5.
Repeat steps
1
and 2. Then slowly increase the measured current in one phase
until the BLKU signal disappears.
6.
Record the measured current and calculate the corresponding negative-sequence
current according to the equation (observe that the currents in the equation are
phasors):
U
+ ⋅
a
U
L2
L3
are the measured phase voltages
3
+
.
j
2
1MRK 506 355-UEN A
(Equation 100)
Line distance protection REL670 2.1 IEC
Commissioning manual
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