ABB Relion REC670 Applications Manual page 69

1MRK 511 358-UEN A
L1 L2
Protected Object
IEC11000027 V3 EN-US
Figure 16: Delta DAB connected three-phase CT set
Where:
1)
2)
3)
4)
Application manual
L3
IL1-IL2
IL2-IL3
IL3-IL1
shows how to connect three individual phase currents from a delta connected three-phase CT set to
three CT inputs of the IED.
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.
CT
=600A
prim
CT =5A
sec
CTStarPoint = ToObject
•
• ConnectionType = Ph-Ph
are three connections made in Signal Matrix Tool (SMT), Application configuration tool (ACT), which
connect these three current inputs to first three input channels of the preprocessing function block
4). Depending on the type of functions which need this current information, more then one
preprocessing block might be connected in parallel to these three CT inputs.
is a Preprocessing block that has the task to digitally filter the connected analog inputs and
calculate:
• fundamental frequency phasors for all three input channels
• harmonic content for all three input channels
• positive, negative and zero sequence quantities by using the fundamental frequency phasors
for the first three input channels (channel one taken as reference for sequence quantities)
These calculated values are then available for all built-in protection and control functions within the
IED, which are connected to this preprocessing function block. For this application most of the
preprocessing settings can be left to the default values.
If frequency tracking and compensation is required (this feature is typically required only for IEDs
installed in the generating stations) then the setting parameters
accordingly.
IED
2
1
3
Analog inputs
4
SMAI2
BLOCK AI3P
REVROT AI1
^GRP2L1 AI2
^GRP2L2 AI3
^GRP2L3 AI4
^GRP2N AIN
IEC11000027-3-en.vsdx
DFTReference shall be set
Section 4
63