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Section 11
Testing functionality by secondary injection
•
•
•
11.8.2.2
Measuring the trip value for the negative sequence function
Measure the trip 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 BLKV 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
EQUATION1818-ANSI V1 EN-US
Where:
V V
EQUATION1820-ANSI V1 EN-US
a
IECEQUATION00022 V2 EN-US
4.
Compare the result with the set value of the negative-sequence operating voltage (consider that the
set value 3V2PU is in percentage of the base voltage VBase).
5.
Repeat steps
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):
×
3
ANSIEQUATION00021 V1 EN-US
Where:
I
ANSIEQUATION00020 V1 EN-US
a
IECEQUATION00022 V2 EN-US
7.
Compare the result with the set value of the negative-sequence operating current. Consider that
the set value 3I2< is in percentage of the base current IBase.
130
Signal 3PH after about 25ms
Signal BLKV after about 50ms
Signal BLKZ after about 200ms
2
=
+
×
+ ×
V
V
a V
a V
2
A
B
C
V
and
A
B
C
p ×
2
j
= ×
= -
+
1
e
0, 5
.
j
3
1
and 2. Then slowly increase the measured current in one phase until the BLKV
=
+
×
+ ×
2
I
I
a
I
a I
2
A
B
C
,
I and I
A
B
C
p ×
2
j
= ×
= -
+
.
1
e
0, 5
j
3
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are the measured phase voltages
3
2
are the measured phase currents
3
2
1MRK 511 409-UUS Rev. K
M1405-46 v12
(Equation 95)
(Equation 96)
Phasor measurement unit RES670
Commissioning manual
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