4.19
Date Code 20170814
Instruction Manual
SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
forming the delta. Thus, for CTCn = 11, the relay uses the following
[CTC(m)] matrix:
that is,
The effect of each compensation on balanced three-phase currents is to rotate
them m • 30° without a magnitude change.
The compensation matrix [CTC(12)] is similar to [CTC(0)], in that it produces
no phase shift (or, more correctly, 360 degrees of shift) in a balanced set of
phasors separated by 120 degrees. However, it removes zero-sequence
components from the winding current, as do all of the matrices having
nonzero values of m.
that is,
We could use this type of compensation in applications having wye-connected
transformer windings (no phase shift) with wye CT connections for each
winding. Using CTCn = 12 for each winding removes zero-sequence
components, just as connection of the CTs in delta would do, but without
producing a phase shift. (One might also use CTCn = 1 or 11 for this same
application, yielding compensation similar to that from connection of the CTs
on both sides in DAB or DAC.)
CTC 11
1
3
-------
1 0 –1
–1 1 0
0 –1 1
=
I1
n
C
IA
n
IC
n
–
3
------------------------------
=
I2
n
C
IB
n
IA
n
–
3
------------------------------
=
I3
n
C
IC
n
IB
n
–
3
------------------------------
=
CTC 12
1
3
---
2 –1 –1
–1 2 –1
–1 –1 2
=
I1
n
C
+2 • IA
n
– IB
n
– IC
n
3
-----------------------------------------------------------
=
I2
n
C
–IA
n
2 • IB
n
– IC
n
+
3
------------------------------------------------------------
=
I3
n
C
–IA
n
– IB
n
+ 2 • IC
n
3
----------------------------------------------------------
=
I1
n
C
+2 • IA
n
IB
n
–
IC
n
–
3
------------------------------------------------------------
=
I2
n
C
–IA
n
+ 2 • IB
n
– IC
n
3
---------------------------------------------------------
=
I3
n
C
–IA
n
– IB
n
+ 2 • IC
n
3
---------------------------------------------------------
=
Summary of Contents for SEL-700G Series
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