Measuring The Operate Value For The Negative Sequence Function - ABB REB670 Commissioning Manual

1MRK 505 372-UEN A
10.8.1.2
Busbar protection REB670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
• 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-US
Where:
U , U and U
L1 L 2 L3
IEC00000275 V1 EN-US
p ×
2
j
= × = -
a 1 e 0, 5
3
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).
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
Section 10
M1405-46 v12
(Equation 22)
129