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 20: Wye connected three-phase CT set with its star point away from the protected object
In the example in figure 20 case everything is done in a similar way as in the above
described example (figure 19). 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.
4.2.4 Setting of voltage channels
As the IED uses primary system quantities the main VT ratios must be known to the IED.
This is done by setting the two parameters VTsec and VTprim for each voltage channel.
The phase-to-phase value can be used even if each channel is connected to a phase-to-
ground voltage from the VT.
Section 4 1MRK 511 286-UUS A
Analog inputs
70
Application manual
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