ABB RED650, Applications Manual

Page: 295 / 454

LoadCurr must be set below the current that will flow on the healthy phase when
one or two of the other phases are faulty and the breaker has opened at remote end.
Calculate the setting according to equation
131 .
min
0.5
Load
Base
I
LoadCurr
I
×
=
EQUATION1320 V1 EN-US
(Equation 131)
where:
ILoadmin is the minimum load current on the line during normal operation conditions.
The timer tLoadOn is used to increase the security of the loss-of-load function for
example to avoid unwanted release due to transient inrush current when energizing
the line power transformer. The loss-of-load function will be released after the
timer
tLoadOn has elapsed at the same time as the load current in all three phases
are above the setting LoadCurr . In normal acceleration applications there is no
need for delaying the release, so set the tLoadOn to zero.
The drop-out timer tLoadOff is used to determine the window for the current
release conditions for Loss-of-load. The timer is by default set to 300ms, which is
judged to be enough to secure the current release.
The setting of the minimum current detector, MinCurr , should be set higher than
the unsymmetrical current that might flow on the non faulty line, when the breaker
at remote end has opened. At the same time it should be set below the minimum
load current transfer during normal operations that the line can be subjected to. By
default,
MinCurr is set to 5% of IBase .
The pick-up timer tLowCurr determine the window needed for pick-up of the
minimum current value used to release the function. The timer is by default set to
200 ms, which is judged to be enough to avoid unwanted release of the function
(avoid unwanted trip).
13.4 Scheme communication logic for residual
overcurrent protection ECPSCH
IP14711-1 v2
13.4.1 Identification
M14882-1 v2
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Scheme communication logic for
residual overcurrent protection
ECPSCH - 85
1MRK 505 393-UEN B
Section 13
Scheme communication
Line differential protection RED650 2.2 IEC 289
Application manual