Event block name
Event names
ARC1
Channel 4 Light OFF
ARC1
Channel 4 Pressure ON
ARC1
Channel 4 Pressure OFF
ARC1
DI Signal ON
ARC1
DI Signal OFF
ARC1
I/I0 Arc> Sensor 1 Fault ON
ARC1
I/I0 Arc> Sensor 1 Fault OFF
ARC1
I/I0 Arc> Sensor 2 Fault ON
ARC1
I/I0 Arc> Sensor 2 Fault OFF
ARC1
I/I0 Arc> Sensor 3 Fault ON
ARC1
I/I0 Arc> Sensor 3 Fault OFF
ARC1
I/I0 Arc> Sensor 4 Fault ON
ARC1
I/I0 Arc> Sensor 4 Fault OFF
ARC1
I/I0 Arc> I/O-unit Fault ON
ARC1
I/I0 Arc> I/O-unit Fault OFF
The function registers its operation into the last twelve (12) time-stamped registers. The table below
presents the structure of the function's register content.
Table. 5.4.31 - 251. Register content.
Date and time
Event
Phase A
current
Phase B
current
Phase C
current
Residual
current
Active
sensors
Used SG
dd.mm.yyyy
hh:mm:ss.mss
Event
name
Trip current
Trip current
Trip current
Trip current
1...4
Setting group
1...8 active
5.4.32 Voltage memory
Certain protection functions (such as impedance or directional overcurrent) use the relay's measured
current and voltage to determine whether the electrical network fault appears to be inside the
protected area. The determination is made by comparing the angle between the operating quantity
(zone/tripping area) and the actual measured quantity. The function then produces an output when the
required terms are met.
In close-in faults the system voltage on the secondary side may fall down to a few volts or close to
nothing. In such cases, when the measured voltage is absent, the fault direction cannot be solved. As
backup, non-directional protection can be used for tripping, but in such cases the selectivity of the
network will reduce. However, an angle memory for voltage can be used to prevent this from
happening. An adjustable voltage level with pre-fault voltage angles can be used as a reference for
fault direction and/or distance. The reference can be set manually for duration. Thanks to the
configurable voltage memory even time-delayed backup tripping can be initiated.
The user can activate voltage memory (and find all related settings) by following this path in relay
settings:
Measurement
→
Transformers
→
VT Module (3U/4U) 1
→
Voltage memory
("Activated"/"Disabled").
The activation of voltage memory depends of following criteria:
A
AQ
Q-M257
-M257
Instruction manual
Version: 2.07
336
© Arcteq Relays Ltd
IM00021
Summary of Contents for AQ-M257
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