ABB Relion 670 Series Applications Manual page 150

Section 8
Current protection
8.3 Instantaneous residual overcurrent protection EFPIOC
(50N)
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 ground-fault protection can provide fast and selective tripping.
The Instantaneous residual overcurrent EFPIOC (50N), which can operate in 15 ms (50 Hz nominal
system frequency) for faults characterized by very high currents, is included in the IED.
8.3.3 Setting guidelines
The parameters for the Instantaneous residual overcurrent protection EFPIOC (50N) are set via the
local HMI or PCM600.
Some guidelines for the choice of setting parameter for EFPIOC (50N) is given.
Common base IED values for primary current (
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 EFPIOC (50N) 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-ground faults and phase-to-phase-to-
ground faults shall be calculated as shown in Figure
the protection are calculated. For a fault at the remote line end this fault current is I
calculation the operational state with high source impedance Z
should be used. For the fault at the home busbar this fault current is I
operational state with low source impedance Z
144
IEC 61850
identification
EFPIOC
IBase ), primary voltage ( VBase ) and primary power
A
© Copyright 2017 ABB. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
50N
IN>>
IEF V1 EN-US
65 and Figure 66. The residual currents (3I
and low source impedance Z
A
. In this calculation the
fA
and high source impedance Z
1MRK 511 401-UUS F
IP14508-1 v3
M14887-1 v4
M12699-3 v5
IP14985-1 v1
M12762-44 v2 M12762-4 v4
M12762-6 v8
) to
0
. In this
fB
B
should be used.
B
Bay control REC670
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