Arcteq AQ-T257, Instruction Manual

Page: 266 / 359

U
L31
Ang Fundamental angle of U
L31
voltage
5 ms
U
L1
Ang Fundamental angle of U
L1
voltage
5 ms
U
L2
Ang Fundamental angle of U
L2
voltage
5 ms
U
L3
Ang Fundamental angle of U
L3
voltage
5 ms
Selection of the used AI channel is made with a setting parameter. In all possible input channel
variations pre-fault condition is presented with 20 ms averaged history value from -20 ms of Start or
Trip event.
Pick-up characteristics
Voltage dependent pick-up and activation of the VTS function is controlled by Voltage low pick-up and
Voltage high detectsetting parameters. If at least one measured voltage of the three are under the set
low value, VTS pick-up will activate. Also if at least two of the three voltages are over high detect value
VTS pick-up will activate. The function constantly calculates the ratio in between of the setting values
and measured magnitude per all three phases.
Table. 5.6.2. - 210. Pick-up characteristics setting
Name Range Step Default Description
Voltage low
pickup
0.00 …
0.50xUn
0.01xUn 0.05xUn If at least one of the measured voltages are under this set value the
function will pick up
Voltage high
detect
0.01 …
40.00xUn
0.01xUn 0.10xUn If at least two of the measured voltages are over this set value the function
will pick up
Angle shift
limit
2.00 …
90.00deg
0.10deg 5.00deg If the difference between the angle in present time and -40ms before is
lower than the set value function will pick up
Line Fuse
fail check
No
Yes
- Yes
Selection if the state of the line fuse will be supervised. The supervised
signal is determined in IOà Fuse-Failure Inputs
Bus Fuse fail
check
No
Yes
- Yes
Selection if the state of the bus fuse will be supervised. The supervised
signal is determined in IOà Fuse-Failure Inputs
The pick-up activation of the function is not directly equal to start-signal generation of the function.
Start signal is allowed if blocking condition is not active. From binary signals the activation of the pick-
up is immediate when the monitored signal is activated.
Voltage transformer supervision can also report several different states of the measured voltage. These
can be seen in the INFO-page of the function in the relay HMI or in AQtivate.
Name Description
Bus dead No voltages
Bus Live VTS Ok All of the voltages are within the set limits
Bus Live VTS Ok SEQ Rev All of the voltages are within the set limits BUT the voltages are in reversed sequence
Bus Live VTS Ok SEQ Undef Voltages are within the set limits BUT sequence cannot be de ned.
Bus Live VTS problem Any of the VTS pick-up conditions are valid!
Function blocking
In the blocking element the block signal is checked in the beginning of each program cycle. Blocking
signal is received from the blocking matrix for the function dedicated input. If the blocking signal is not
activated when the pick-up element activates, a START signal is generated and the function proceeds
to the time characteristics calculation.
AQ-T257
Instruction manual
Version: 2.00
265 © Arcteq Relays Ltd