ABB RELION Series Technical Manual page 383

1MRS758755 A
REC615 and RER615
Technical Manual
For fault direction determination, the fundamental frequency admittance and
harmonic susceptances are summed together in phasor format. The result is the sum
admittance phasor defined as below.
1
 
Y Re Y j Im
= + ⋅
osum
0
 
GUID-6660AD60-0694-4808-8146-A1F053DA5F7C V1 EN
The polarity of the polarizing quantity (residual voltage) can be
changed (rotated by 180 degrees) by setting the Pol reversal
parameter to "True" or by switching the polarity of the residual
voltage measurement wires.
Fault direction determination
If an earth fault is detected by the GFC module, the fault direction is evaluated based
on the calculated sum admittance phasor
admittance calculation module. To obtain dependable and secure fault direction
determination regardless of the fault type (transient, intermittent, restriking,
permanent, high or low ohmic), the fault direction is calculated using a special
filtering algorithm, Cumulative Phasor Summing (CPS) technique. This filtering
method is advantageous during transient, intermittent and restriking earth faults with
dominantly non-sinusoidal or transient content. It is equally valid during continuous
(stable) earth faults.
The concept of CPS is illustrated in
measured sum admittance phasors together in phasor format in chronological order
during the fault. Using the discrete sum admittance phasors
instants (t ...t ), the corresponding accumulated sum admittance phasor
1 5
calculated. This phasor is used as directional phasor in determining the direction of the
fault.
( ) ( )
Y t Y t
=
osum CPS _ osum
1 1
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Y ( ) t Y ( ) t
=
osum CPS _ osum
2 1
GUID-696EFC44-7AF4-45A9-A3F4-11C153143D55 V1 EN
Y ( ) t Y ( ) t
=
osum CPS _ osum
3 1
GUID-A18538B4-EFCD-4844-AEFB-0BB92358582A V1 EN
Y ( ) t Y ( ) t
=
osum CPS _ osum
4 1
GUID-EBDE2421-0F49-4141-87E2-433DF64503C9 V1 EN
9
 
1 n 1
Y Y G j B
+ ∑  = + ⋅

0 0 o
 
n 2
=
obtained from the Multi-frequency
Y
osum
Figure 197. It is the result of adding values of the
Y ( ) t
+
osum
2
Y ( ) t Y ( ) t
+ +
osum osum
2 3
Y ( ) t Y ( ) t
+ + +
osum osum
2 3
Section 4
Protection functions
osum
(Equation 34)
in different time
Y
osum
Y
osum CPS
(Equation 35)
(Equation 36)
(Equation 37)
Y ( ) t
osum
4
(Equation 38)
is
_
377