ABB REB670 Applications Manual page 77

1MRK 505 337-UUS -
A B
CT 800/1
Star Connected
Protected Object
ANSI11000026 V4 EN
Figure 22: Wye connected three-phase CT set with its star point away from the protected object
Application manual
C
IC
IB
IA
In the example in figure 22
described example (figure
CTStarPoint of the used current inputs on the TRM (item 2 in the figure):
• CTprim=600A
• CTsec=5A
• CTWyePoint=FromObject
Inside the IED only the ratio of the first two parameters is used. 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 the figure below.
IED
2
3
1
case everything is done in a similar way as in the above
21). The only difference is the setting of the parameter
Section 4
Analog inputs
4
SMAI_20_2
BLOCK AI3P
REVROT AI1
5
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
ANSI11000026-4-en.vsd
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