Event block name
Event names
NEF2
Start ON
NEF2
Start OFF
NEF2
Trip ON
NEF2
Trip OFF
NEF2
Block ON
NEF2
Block OFF
NEF3
Start ON
NEF3
Start OFF
NEF3
Trip ON
NEF3
Trip OFF
NEF3
Block ON
NEF3
Block OFF
NEF4
Start ON
NEF4
Start OFF
NEF4
Trip ON
NEF4
Trip OFF
NEF4
Block ON
NEF4
Block OFF
The function registers its operation into the last twelve (12) time-stamped registers. The register of the
function records the ON event process data for START, TRIP or BLOCKED. The table below
presents the structure of the function's register content.
Table. 5.3.3 - 42. Register content.
Date and time
Event
Fault
type
Pre-trigger
current
Fault
current
Pre-fault
current
Trip time
remaining
Used SG
dd.mm.yyyy
hh:mm:ss.mss
Event
name
A-G-
R…C-G-
F
Start/trip -20
ms current
Start/Trip
current
Start -200ms
current
0 ms...1800s
Setting
group 1...8
active
5.3.4 Negative sequence overcurrent/ phase current reversal/ current unbalance
protection (I2>; 46/46R/46L)
The current unbalance function is used for instant and time-delayed unbalanced network protection
and for detecting broken conductors. The number of stages in the function depends on the
relay model. The operating decisions are based on negative and positive sequence current magnitudes
which the function constantly measures. In the broken conductor mode (I2/I1) the minimum allowed
loading current is also monitored in the phase current magnitudes.
There are two possible operating modes available: the I2 mode monitors the negative sequence
current, while the I2/I1 mode monitors the ratio between the negative sequence current and the
positive sequence current. The relay calculates the symmetrical component magnitudes in use from
the phase current inputs
I
L1
,
I
L2
and
I
L3
. The zero sequence current is also recorded into the registers
as well as the angles of the positive, negative and zero sequence currents in order to better verify any
fault cases. The blocking signal and the setting group selection control the operating characteristics of
the function during normal operation, i.e. the user or user-defined logic can change function
parameters while the function is running.
A
AQ
Q-T256
-T256
Instruction manual
Version: 2.06
© Arcteq Relays Ltd
IM00028
51
Summary of Contents for AQ-T256
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