Real-time info displayed by the function
The relays Info-page displays useful information in real time of the state of the protection function either
through relays HMI display or with AQtivate software when connection there is a connection to relay
and Live Edit-mode is activated.
Table. 5.4.4. - 70. Info displayed by the function
Name
Unit
Description
Operating angle now
Deg
Positive sequence current angle in relation to positive sequence voltage
Expected operating time
s
Displays the expected operating time in case a fault occurs
Time remaining to trip
s
When the relay has picked up and is counting time towards pick-up
Imeas/Iset at the moment
Im/Iset
Ratio between positive sequence current and the pick-up value.
Pick-up characteristics
Pick-up of the DOC function is controlled by Iset setting parameter, which de nes the maximum
allowed measured current before action from the function. The function constantly calculates the ratio
in between the Iset and measured magnitude (Im) per all three phases. Reset ratio of 97 % is inbuilt in
the function and is always related to the Iset value. The setting value is common for all measured
phases and single-, dual- or all phases Im exceed of the Iset value will cause pick-up operation of the
function.
Trip characteristic can be set to directional or non-directional. In non-directional mode only positive
sequence current magnitude pick-up value must be ful lled for the function to trip. In directional mode
the fault must be in the monitored direction as well to ful ll the terms to trip. By default tripping area is
±88° (176°) and reference angle is based on calculated positive sequence voltage U1 angle. In case
U1 voltage is not available and only line to line voltages are measured the angle reference is based on
healthy line to line voltage and during short circuit to impedance calculation. If voltage drops below 1V
secondary the angle memory is used for 0.5 seconds. Angle memory forces the angle reference to the
value that was measured or calculated before the fault. Angle memory captures the measured voltage
angle 100 ms before the fault starts. After 0.5 seconds the angle memory is not used anymore, and
reference voltage is forced to 0°. Inbuilt reset ratio for the trip area angle is 2°.
Table. 5.4.4. - 71. Pick-up characteristics setting
Name
Description
Range
Step
Default
Iset
Pick-up setting
0.10 … 40.00xIn
0.01xIn
1.20 x In
Center
Pick-up center
-180.0…180.0°
0.1°
0°
Angle
Pick-up area
±1.0…170.0°
0.1°
±88°
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.
AQ-F255
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
70
