ABB REG670 Applications Manual page 80

Section 4
Analog inputs
L1
CT 800/1
Star Connected
Protected Object
IEC11000026 V4 EN
Figure 19: Star connected three-phase CT set with its star point away from the protected object
74
L2 L3
IN
IL3
IL2
IL1
In the example, everything is done in a similar way as in the above described example
(Figure 18). The only difference is the setting of the parameter CTStarPoint of the
used current inputs on the TRM (item 2 in Figure
• 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 three-phase CT set
connected to the IED as shown in Figure 19.
Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
IED
2
1
3
19
1MRK 502 071-UEN -
4
SMAI2
BLOCK AI3P
REVROT AI1
5
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AI N
IEC11000026-4-en.vsdx
and 18):
Application manual