ABB REL670 2.2 IEC Applications Manual page 83

1MRK 506 369-UEN B
L1
CT 800/1
Star Connected
Protected Object
IEC06000644 V4 EN-US
Figure 15: Star connected three-phase CT set with its star point away from the protected object and the
residual/neutral current connected to the IED
Line distance protection REL670 2.2 IEC
Application manual
L2 L3
IN
IL3
IL2
IL1
Where:
1) Shows how to connect three individual phase currents from a star connected three-phase
CT set to the three CT inputs of the IED.
2) Shows how to connect residual/neutral current from the three-phase CT set to the fourth
input in the IED. It shall be noted that if this connection is not made, the IED will still
calculate this current internally by vectorial summation of the three individual phase
currents.
3) Is the TRM where these current inputs are located. It shall be noted that for all these
current inputs the following setting values shall be entered.
CTprim =800A
•
• CTsec =1A
CTStarPoint =FromObject
•
ConnectionType =Ph-N
•
The ratio of the first two parameters is only used inside the IED. The third parameter as set
in this example will have no influence on measured currents (that is, currents are already
measured towards the protected object).
4) Are three connections made in the Signal Matrix tool (SMT) and Application configuration
tool (ACT), which connects these three current inputs to the first three input channels on
the preprocessing function block 6). Depending on the type of functions, which need this
current information, more than one preprocessing block might be connected in parallel to
these three CT inputs.
Table continues on next page
IED
3
1
4
2
Section 4
Analog inputs
6
SMAI2
BLOCK AI3P
REVROT AI1
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
5
IEC06000644-4-en.vsdx
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