ROA: Relay operate angle for zero sequence directional feature. It is used to
differentiate an internal fault and an external fault based on measured zero sequence
current and neutral current.
CTFactorPri1
: A factor to allow a sensitive function also at multi-breaker arrangement
where the rating in the bay is much higher than the rated current of the transformer
winding. The stabilizing can then be high so an unnecessary high fault level can be
required. The setting is normally 1.0 but in multi-breaker arrangement the setting shall
be CT primary rating/IBase.
CTFactorPri2: A factor to allow a sensitive function also at multi-breaker arrangement
where the rating in the bay is much higher than the rated current of the transformer
winding. The stabilizing can then be high so an unnecessary high fault level can be
required. The setting is normally 1.0 but in multi-breaker arrangement the setting shall
be CT primary rating/IBase.
CTFactorSec1: See setting CTFactorPri1. Only difference is that CTFactorSec1 is
related to W2 side.
CTFactorSec2: See setting CTFactorPri2. Only difference is that CTFactorSec2 is
related to W2 side.
7.4 Additional security logic for differential protection
LDRGFC (11)
GUID-0E064528-0E70-4FA1-87C7-581DADC1EB55 v2
7.4.1 Identification
GUID-3081E62B-3E96-4615-97B8-2CCA92752658 v2
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Additional security logic for differential
protection
LDRGFC - 11
7.4.2 Application
GUID-93AF4444-C7ED-4DF5-9379-176DF17AE22C v4
Additional security logic for differential protection LDRGFC
(11) can help the security
of the protection especially when the communication system is in abnormal status or
for example when there is unspecified asymmetry in the communication link. It
reduces the probability for mal-operation of the protection. LDRGFC (11) is more
sensitive than the main protection logic to always release operation for all faults
detected by the differential function. LDRGFC (11) consists of four sub functions:
Section 7 1MRK 504 163-UUS A
Differential protection
184 Transformer protection RET670 2.2 ANSI
Application manual
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