ABB Relion 670 series - Page 84

7
8
9
10
11
12
1
2
3
4
5
6
A
I
A
I
B
I
C
B C
Protected Object
CT 800/1
Wye Connected
IA
IB
IC
AI 01 (I)
AI 02 (I)
AI 03 (I)
AI 04 (I)
AI 05 (I)
AI 06 (I)
IN
IED
1
3
4
2
5
ANSI06000644-2-en.vsd
6
SMAI2
BLOCK AI3P
AI1
AI2
AI3
AI4
AIN
^GRP2_B
^GRP2_A
^GRP2_C
^GRP2N
TYPE
ANSI06000644 V2 EN
Figure 15: Wye connected three-phase CT set with its wye point away from the protected object and the residual/
neutral current connected to the IED
Where:
1) Shows how to connect three individual phase currents from a wye connected three-phase CT set
to the three CT inputs of the IED.
2) Shows how to connect residual/neutral current from the three-phase CT set to the fourth input in
the IED. It shall be noted that if this connection is not made, the IED will still calculate this current
internally by vectorial summation of the three individual phase currents.
3)
Is the TRM where these current inputs are located. It shall be noted that for all these current inputs
the following setting values shall be entered.
•
CTprim =800A
• CTsec =1A
• CTStarPoint =FromObject
• ConnectionType =Ph-N
The ratio of the first two parameters is only used inside the IED. The third parameter as set in this
example will have no influence on measured currents (that is, currents are already measured
towards the protected object).
4) Are three connections made in the Signal Matrix tool (SMT) and Application configuration tool
(ACT), which connects these three current inputs to the first three input channels on the
preprocessing function block 6). Depending on the type of functions, which need this current
information, more than one preprocessing block might be connected in parallel to these three CT
inputs.
Table continues on next page
Section 4 1MRK 506 369-UUS -
Analog inputs
78 Line distance protection REL670 2.2 ANSI
Application manual