ABB REG670 Applications Manual page 81

1MRK 502 071-UEN -
L1
CT 800/1
Star Connected
Protected Object
IEC06000644 V4 EN
Figure 20: Star connected three-phase CT set with its star point away from the protected object and the
residual/neutral current connected to the IED
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
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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