4573
71
DIF1
29
LV I0d> Block Off
4574
71
DIF1
30
LV I0d> Trip On
4575
71
DIF1
31
LV I0d> Trip Off
Table below is presents the structure of DIF function register content. This information is available in 12
last recorded events.
Table. 5.4.18. - 159. Register content
Date & Time
Event
code
L1 Bias
current
L1 Diff
current
L1 Char
current
L2 Bias
current
L2 Diff
current
L2 Char
current
dd.mm.yyyy
hh:mm:ss.mss
4544-
4575 Descr.
Registered
L1 Bias
current
Registered
L1 Diff
current
Registered L1
max diff current
with bias
Registered
L2 Bias
current
Registered
L2 Diff
current
Registered L2
max diff current
with bias
L3 Bias
current
L3 Diff
current
L3 Char current
HV I0d> Bias
current
HV I0d>
Differential
current
HV I0d>
Characteristics current
Registered
L3 Bias
current
Registered
L3 Diff
current
Registered L3 max
diff current with bias
Registered HV side
REF Bias current
Registered HV
side REF Diff
current
Registered HV side REF
max diff current with bias
LV I0d> Bias current
LV I0d> Differential
current
LV I0d> Characteristics
current
SG in use
Ftype
Registered LV side REF
Bias current
Registered LV side REF
Diff current
Registered LV side REF max diff
current with bias
Used
setting
group
Detected fault type
(faulty phases)
5.4.19. Voltage memory function
Certain protection functions such as, impedance or directional overcurrent, are using the current and
voltage measured at the relay to determine if the electrical network fault appears to be inside protected
area. The determination is made by comparing the angle between the operating quantity (zone/trip
area) to actual measured quantity. The function will produce an output in case required terms are met.
In close-in faults the system voltage on secondary side may fall under several volts or close to nothing.
In such case when measured voltage is absent, the fault direction is not possible to be solved. As
backup, un-directional protection can be used for tripping, but in such cases selectivity of network will
reduce. To prevent this from happening, an angle memory for voltage can be used. Adjustable voltage
level with pre-fault voltage angles can be used as a reference for fault direction/distance, for duration
that can be set manually. Due to con gurable voltage memory, even time delayed backup tripping can
be initiated.
Voltage memory activation and all related settings are found at
Measurements
→
Transformers
→
VT
Module (3/4U) 1
→
Voltage memory
(activated/disabled)
Activation of voltage memory depends of following criteria’s:
1. All used line-to-line or line-to-neutral voltages need to be below set “VMEM activation voltage”.
2. Least one phase current must be higher than set “Measured current condition 3I>”. This setting
limit is optional.
AQ-T257
Instruction manual
Version: 2.00
179
© Arcteq Relays Ltd