ABB RED670 - Measuring the Operate Value for the Negative Sequence Function

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 “of
f” 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
11.9.2.2 Measuring the operate value for the negative sequence function
M1405-46 v12
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
21
2
⋅+⋅+⋅UU UU
LL2L3
= aa
EQUATION707 V2 EN-US (Equation 104)
Where:
U
L1
, U
L2
and U
L3
IEC00000275 V1 EN-US
are the measured phase voltages
2
3
3
1 0,5
2
j
a e j
p ×
= × = - +
.
IECEQUATION00022 V2 EN-US
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).
Section 11 1MRK 505 378-UEN A
Testing functionality by secondary injection
216 Line differential protection RED670 2.2 IEC
Commissioning manual