ABB Remote I/O RIO600, Installation And Commissioning Manual

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earth-fault ignition moment. Therefore, setting Revert Time should
have sufficient big value, at least 300 ms.
Faulted phase selection
The Faulted phase selection module provides information about the faulted phase (A,
B or C) during a single-phase earth fault.
The faulted phase is identified by evaluation of the following equations:
FAULTED PHASE A
=
−
−
+
( )












abs
I I
I
I I
B C
A
B C
∆ ∆
∆
∆ ∆
1 1
1
1 1
2

GUID-2F1B1452-1228-4938-B1A4-3FD5AB349F8C V1 EN
(Equation 20)
FAULTED PHASE B
=
−
−
+
( )












abs
I I
I
I I
C A
B
C A
∆ ∆
∆
∆ ∆
1 1
1
1 1
2

GUID-4A1CC3EC-B50A-4D97-9A71-C7F353D6F18C V1 EN
(Equation 21)
FAULTED PHASE C
=
−
−
+
( )












abs
I I
I
I I
A B
C
A B
∆ ∆
∆
∆ ∆
1 1
1
1 1
2

GUID-7155A708-DFC6-4A61-B643-D341DA65442D V1 EN
(Equation 22)
where
ΔI
A
= I
A
(t
FLT
) - I
A
(t
PRE_FLT
) = change of phase A current phasor due to earth fault
ΔI
B
= I
B
(t
FLT
) – I
B
(t
PRE_FLT
) = change of phase B current phasor due to earth fault
ΔI
C
= I
C
(t
FLT
) – I
C
(t
PRE_FLT
) = change of phase C current phasor due to earth fault
Faulted phase is identified by comparing the magnitudes of Equations 20 - 22 . If
Equation 20 has a minimum value, the faulted phase is A. If Equation 21 has a
minimum value, the faulted phase is B. If Equation 22 has a minimum value, the
faulted phase is C.
Actual implementation uses Cumulative Phasor Summing (CPS) calculation. This
filtering method is especially advantageous during transient, intermittent and re-
striking earth faults with dominantly non-sinusoidal or transient content. But it is
equally valid during continuous (stable) earth faults. The concept of CPS is illustrated
in the figure below.
1MRS757488 H
Section 6
Commissioning
RIO600 153
Installation and Commissioning Manual