ABB Remote I/O RIO600, Руководство по установке и пусконаладке

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FPIPTOC_Oper
General
fault
criterion
Faulted
phase
selection
I_A
I_B
I_C
FPIPTOC_Start
Fault
passage
indicator
GUID-8F92E063-8E83-48B1-B2DD-DCF6A21E6395 V1 EN
Figure 83: Functional module diagram
General fault criterion (GFC)
The General fault criterion (GFC) module monitors the presence of earth fault in the
network. There are two fault detection methods evaluated in parallel based on residual
current (I
o
) and earth-fault current (I
EF
).
Residual current amplitude I
o
can be derived from phase currents as:
I
o
= 3·abs(I
0
) = 3·abs(I
A
+ I
B
+ I
C
)/3
where
I
0
= Zero-sequence current phasor
In order to estimate single-phase earth-fault current, threefold negative-sequence
current component due to earth fault is used (phase A as reference, a=cos(120
o
) +
j·sin(120
o
), phase rotation: A-B-C). Estimated fundamental frequency earth-fault
current amplitude can be derived from phase currents as:
I
EF
= 3·I
2
= I
A
+ a
2
· I
B
+ a· I
C
I
EF
= abs(I
EF
)
where
I
2
= Negative-sequence current phasor
Earth-fault detection is based on monitoring the amplitude of residual current (I
o
) and
earth fault current (I
EF
) and by comparing them to setting values, Residual Start Cur
and EF Start Cur , respectively.
I
o
>Residual Start Cur
GUID-1C757E20-2395-4D0C-AAB1-01002674E9D4 V1 EN
(Equation 18)
I
EF
>EF Start Cur
GUID-A18015C7-36AD-4450-9B8D-7699A3DBCB12 V1 EN
(Equation 19)
Setting Residual Start Cur must be set above the highest residual
current value measured during the healthy state.
1MRS757488 H
Section 6
Commissioning
RIO600 151
Installation and Commissioning Manual