Hitachi Relion 670 Series Applications Manual page 157

1MRK506375-UEN Rev. N
HarmRestrain2: To block the operation of step 2 from the 2
function should be used when there is a risk if power transformer inrush currents might cause
unwanted trip. It can be set Off/On.
DirMode2: To set the directional mode of step 2. The possible modes are Non-directional/Forward/
Reverse.
ActLowVolt2: To define directional step behavior when the measured voltage is below set LowVolt
level. The possible modes of operation are Non-directional/block/Memory. It is set to Memory by
default.
8.3 Instantaneous residual overcurrent protection
EFRWPIOC
8.3.1 Identification
Function description
Instantaneous residual overcurrent
protection
8.3.2 Application
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
The parameters for the Instantaneous residual overcurrent protection EFRWPIOC are set via the
local HMI or PCM600.
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: 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
are calculated. For a fault at the remote line end this fault current is I
operational state with high source impedance Z
the fault at the home busbar this fault current is I
source impedance Z
Railway application RER670
Application manual
IEC 61850
identification
EFRWPIOC
58 and Figure 59. The residual currents (3I
and high source impedance Z
A
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nd
harmonic restrain function. This
IEC 60617 ANSI/IEEE C37.2
identification device number
50N
IN>>
IEF V1 EN-US
. In this calculation the
fB
and low source impedance Z
A
. In this calculation the operational state with low
fA
should be used.
B
Section 8
Current protection
GUID-9131D7D1-2F18-4387-8208-07CA9DEB20CC v1
M14887-1 v4
M12699-3 v5
IP14985-1 v1
M12762-44 v2 M12762-4 v4
M12762-6 v9
) to the protection
0
should be used. For
B
151