ABB REC650 Technical Manual page 204

Section 9
Secondary system supervision
198
• the zero-sequence voltage 3U
• the zero-sequence current 3I
• the negative sequence current 3I
• the negative sequence voltage 3U
The measured signals are compared with their respective set values 3U0< and 3I0>,
3U2< and 3I2>.
The function enable the internal signal FuseFailDetZeroSeq if the measured zero-
sequence voltage is higher than the set value 3U0> and the measured zero-sequence
current is below the set value 3I0<.
The function enable the internal signal FuseFailDetNegSeq if the measured negative
sequence voltage is higher than the set value 3U2> and the measured negative
sequence current is below the set value 3I2<.
A drop off delay of 100 ms for the measured zero-sequence and negative sequence
current will prevent a false fuse failure detection at un-equal breaker opening at the
two line ends.
Sequence Detection
3I0<
IL1
Zero
sequence
filter
IL2
Negative
sequence
IL3
filter
3I2<
3U0>
UL1
Zero
sequence
filter
UL2
Negative
sequence
UL3
filter
3U2>
IEC10000036 V2 EN
Figure 90: Simplified logic diagram for sequence detection part
The calculated values 3U
HMI and monitoring tool in PCM600.
0
0
2
2
100 ms
a
a>b
t
b
100 ms
a
a>b
t
b
a
a>b
b
a
a>b
b
, 3I , 3I and 3U are available as service values on local
0 0 2 2
1MRK 511 287-UEN A
CurrZeroSeq
3I0
CurrNegSeq
3I2
FuseFailDetZeroSeq
AND
FuseFailDetNegSeq
AND
VoltZeroSeq
3U0
VoltNegSeq
3U2
IEC10000036-2-en.vsd
Technical manual