ABB REC670 Applications Manual page 77

1MRK 511 401-UUS A
A B
CT 800/1
Wye Connected
Protected Object
ANSI11000026 V5 EN-US
Figure 14: Wye connected three-phase CT set with its wye point away from the protected object
Bay control REC670 2.2 ANSI
Application manual
C
IC
IB
IA
In the example, everything is done in a similar way as in the above described example
(Figure 13). 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
• CTWyePoint=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 14.
IED
2
3
1
14 and 13):
Section 4
Analog inputs
4
SMAI_20_2
BLOCK AI3P
REVROT AI1
^GRP2_A 5 AI2
^GRP2_B AI3
^GRP2_C AI4
^GRP2N AIN
ANSI11000026-5-en-.vsd
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