ABB RER670 Applications Manual page 58

Section 4
Analog inputs
52
• CTprim=600A
• CTsec=5A
• CTStarPoint=FromObject
The ratio of the first two parameters is only used inside the IED. The third
parameter as set in this example will negate the measured currents in order to
ensure that the currents are measured towards the protected object within the IED.
A third alternative is to have the residual/neutral current from the two-phase CT set
connected to the IED as shown in Figure 14.
L1 L2
CT 600/5A
Star Connected
Protected Object
IEC16000138 V1 EN-US
Figure 14: Star connected two-phase CT set with its star point away from the
protected object and the residual/neutral current connected to the
IED
Where:
1) Shows how to connect two individual phase currents from a star connected two-phase CT
set to the two CT inputs of the IED.
2) Shows how to connect residual/neutral current from the two-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 two 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 =600A
•
• CTsec =5A
CTStarPoint =FromObject
•
The ratio of the first two parameters is only used inside the IED. The third parameteras set
in this example will negate the measured currents in order to ensure that the currents are
measured towards the protected object within the IED.
Table continues on next page
IED
3
1
IN
IL2
IL1
2
1MRK 506 375-UEN A
6
4
SMAI2
BLOCK AI2P
^GRP2L1
AI1
5
^GRP2L2
AI2
^GRP2L1L2 AI3
^GRP2N AI4
AIN
5
IEC16000138-1-en.vsdx
Railway application RER670 2.2 IEC
Application manual