ABB Relion 670 Series Applications Manual page 146

Section 8
Current protection
D ³
t 40
EQUATION1266 V1 EN-US
where it is considered that:
the operate time of overcurrent protection B1 is 40 ms
the breaker open time
the resetting time of protection A1
the additional margin
8.3 Instantaneous residual overcurrent protection EFPIOC
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.
The Instantaneous residual overcurrent EFPIOC, 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 are set via the
local HMI or PCM600.
Some guidelines for the choice of setting parameter for EFPIOC is given.
Common base IED values for primary current (
power (
GlobalBaseSel : This is used to select GBASVAL function for reference of base values.
The basic requirement is to assure selectivity, that is EFPIOC 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
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
used.
140
+ + +
ms 100 ms 40 ms
SBase ) are set in the global base values for settings function GBASVAL.
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=
40 ms 220 ms
is 100 ms
is 40 ms and
is 40 ms
IEC 61850 IEC 60617
identification identification
EFPIOC
IN>>
IEF V1 EN-US
IBase ), primary voltage ( UBase ) and primary
65 and Figure 66. The residual currents (3I
and high source impedance Z
A
1MRK 511 401-UEN Rev. K
(Equation 35)
ANSI/IEEE C37.2
device number
50N
. In this
fB
and low source impedance Z
A
. In this calculation the
fA
should be
B
Bay control REC670
Application manual
IP14508-1 v3
M14887-1 v4
M12699-3 v5
IP14985-1 v1
M12762-44 v2 M12762-4 v4
M12762-6 v8
) to the
0
B