ABB RET670 - Measuring the Trip Value for the Zero-Sequence Function

2
2
3
A B C
V V a V a V× = + × + ×
EQUATION1818-ANSI V1 EN (Equation 104)
Where:
A B C
andV V V
EQUATION1820-ANSI V1 EN
are the measured phase voltages
2
3
3
1 0,5
2
j
a e j
p ×
= × = - +
.
IECEQUATION00022 V2 EN
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
1 and 2. Then slowly increase the measured current in one phase until
the BLKV 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):
2
2
3
A B C
I I a I a I× = + × + ×
ANSIEQUATION00021 V1 EN (Equation 105)
Where:
A B C
I I and I ,
ANSIEQUATION00020 V1 EN
are the measured phase currents
2
3
3
1 0,5
2
j
a e j
p ×
= × = - +
.
IECEQUATION00022 V2 EN
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.
11.9.2.3 Measuring the trip value for the zero-sequence function
Measure the trip value for the zero-sequence function, if included in the IED.
Section 11 1MRK 504 165-UUS -
Testing functionality by secondary injection
232 Transformer protection RET670 2.2 ANSI
Commissioning manual