ABB RELION RER670, Applications Manual

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3) These two connections are the links between the two phase current inputs and the two
input channels of the preprocessing function block 4).
4) The preprocessing block that has the task to digitally filter the connected analog inputs and
calculate:
• fundamental frequency phasors for the two input channels
• harmonic content for the two input channels
• positive and zero sequence quantities by using the fundamental frequency phasors
for the first two 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.
5) AI2P in the SMAI function block is a grouped signal which contains all the data about the
phases L1, L2, L1–L2, and neutral quantity; in particular the data about fundamental
frequency phasors, harmonic content, positive sequence and zero sequence quantities are
available.
AI1, AI2, AI3, AI4 are the output signals from the SMAI function block which contain the
fundamental frequency phasors and the harmonic content of the corresponding input
channels of the preprocessing function block.
AIN is the signal which contains the fundamental frequency phasors and the harmonic
content of the neutral quantity. In this example, GRP2N is not connected so this data is
calculated by the preprocessing function block on the basis of the inputs GRPL1 and
GRPL2. If GRP2N is connected, the data reflects the measured value of GRP2N.
Another alternative is to have the star point of the two-phase CT set as shown in
Figure
13 :
L1
IL
1
IL
2
L2
Protected Object
IL1
IL2
IED
IEC16000137-1-en.vsdx
4
1
2
3
IN
SMAI2
BLOCK
^GRP2L1
^GRP2L2
^GRP2L1L2
^GRP2N AI2P
AI1
AI2
AI3
AI4
AIN
5 CT 600/5A
Star Connected
IEC16000137 V1 EN-US
Figure 13: Star connected two-phase CT set with its star point away from the
protected object
In the example, everything is done in a similar way as in the above described
example (Figure
12 ). The only difference is the setting of the parameter
CTStarPoint of the used current inputs on the TRM (item 2 in Figure 12 and 13 ):
1MRK 506 375-UEN A
Section 4
Analog inputs
Railway application RER670 2.2 IEC 51
Application manual