ABB RELION RER670, Руководство по применению

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8.3.2 Application
M12699-3 v5
In many applications, when fault current is limited to a defined value by the object
impedance, an instantaneous earth-fault protection can provide fast and selective
tripping.
8.3.3 Setting guidelines
IP14985-1 v1
M12762-44 v2 M12762-4 v4
The parameters for the Instantaneous residual overcurrent protection EFRWPIOC
are set via the local HMI or PCM600.
M12762-6 v8
Common base IED values for primary current ( IBase ), primary voltage ( UBase )
and primary power ( SBase ) are set in the global base values for settings function
GBASVAL.
GlobalBaseSel : This is used to select GBASVAL function for reference of base
values.
The basic requirement is to assure selectivity, that is EFRWPIOC shall not be
allowed to operate for faults at other objects than the protected object (line).
For a normal line in a meshed system single phase-to-earth faults and phase-to-
phase-to-earth faults shall be calculated as shown in Figure
52 and Figure 53 . The
residual currents (3I
0
) to the protection are calculated. For a fault at the remote line
end this fault current is I
fB
. In this calculation the operational state with high source
impedance Z
A
and low source impedance Z
B
should be used. For the fault at the
home busbar this fault current is I
fA
. In this calculation the operational state with
low source impedance Z
A
and high source impedance Z
B
should be used.
~ ~
Z
A
Z
B
Z
L
A B
IED
I
fB
Fault
IEC09000022-1-en.vsd
IEC09000022 V1 EN-US
Figure 52: Through fault current from A to B: I
fB
1MRK 506 375-UEN A
Section 8
Current protection
Railway application RER670 2.2 IEC 167
Application manual