Table. 5.3.2. - 51. Register content.
Date and time
Event
code
Fault
type
Max I0
m
/I0
set
Used SG
dd.mm.yyyy
hh:mm:ss.mss
8642-8643
Descr.
L1-G…L1-
L2-L3
The ratio between the maximum residual current and
the pick-up current value.
Setting
group 1...8 active
5.3.3. Directional overcurrent (Idir>; 67)
The directional overcurrent function is used for directional overcurrent and short-circuit alarms. The
operating decisions are based on phase current magnitudes which the function constantly
measures. The monitored phase current magnitudes are equal to RMS values. The setting group
selection controls the operating characteristics of the function during normal operation, i.e. the user or
user-de ned logic can change function parameters while the function is running.
The output of the function is the ALARM signal. The directional overcurrent function uses a total of
eight (8) separate setting groups which can be selected from one common source.
The operational logic consists of the following:
input magnitude selection
input magnitude and angle processing
saturation check
threshold comparator
output processing.
The inputs for the function are the following:
operating mode selections
setting parameters
digital inputs and logic signals
measured and pre-processed current magnitudes.
The function's output ALARM signal can be used for direct I/O controlling and user logic programming.
The function generates general time-stamped ON/OFF events to the common event buffer from the
output signal. The time stamp resolution is 1 ms. The function also provides a resettable cumulative
counter for ALARM events.
Measured input
The function block uses analog current and voltage measurement values and always uses peak-to-
peak measurement from samples. The monitored magnitude is equal to the fundamental frequency
RMS.
The fault current angle is based on a comparison between the positive sequence voltage
U
1
and
positive sequence current
I
1
. If the positive sequence voltage is not available (three line-to-line voltages
but no U
0
), the voltage angle is based on a faulty phase line-to-line voltage. If the voltage drops below
1 V in the secondary side during a fault, the voltage memory is used for 0.5 seconds. After that the
reference angle of the voltage is forced to 0°.
Table. 5.3.3. - 52. Measurement inputs of the Idir> function.
Signal
Description
Time base
IL1RMS
Fundamental RMS measurement of phase L1 (A) current
5 ms
IL2RMS
Fundamental RMS measurement of phase L2 (B) current
5 ms
AQ-E215
Instruction manual
Version: 2.01
© Arcteq Relays Ltd
70