Protected Object
CT 800/1
Star Connected
IED
ANSI11000026-4-en.vsd
4
1
2
3
A
I
A
I
B
I
C
B C
IA
IB
IC
SMAI_20_2
BLOCK
REVROT
^GRP2L1
^GRP2L2
^GRP2L3
^GRP2N
AI3P
AI1
AI2
AI3
AI4
AIN
5
ANSI11000026 V4 EN
Figure 9: Wye connected three-phase CT set with its star point away from the protected object
In the example in figure 9 case everything is done in a similar way as in the above
described example (figure 8). The only difference is the setting of the parameter
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.
1MRK504116-UUS C Section 3
IED application
43
Application manual
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