Table. 5.2.1 - 18. Harmonic voltage measurements.
Name
Unit
Range
Step Default
Description
Harmonics
calculation values
("Harm Abs.or
Perc.")
-
0: Percent
1: Absolute
-
0:
Percent
Defines whether the harmonics are calculated as
percentages or absolute values.
Harmonics
display
-
0: Per unit
1: Primary V
2: Secondary V
-
0: Per
unit
Defines how the harmonics are displayed: in p.u. values, as
primary voltage values, or as secondary voltage values.
Maximum
harmonics value
("UxMaxH")
V
0.00…100000.00
V
0.01
V
-
Displays the maximum harmonics value of the selected
voltage input Ux.
Fundamental
frequency
("Ux Fund")
V
0.00…100000.00
V
0.01
V
-
Displays the voltage value of the fundamental frequency
value (RMS) of the selected voltage input Ux.
Ux harmonics
(2
nd
...31
st
harmonic)
V
0.00...100000.00
V
0.01
V
-
Displays the selected harmonic from the voltage input Ux.
5.2.2 Frequency tracking and scaling
Measurement sampling can be set to the frequency tracking mode or to the fixed user-
defined frequency sampling mode. The benefit of frequency tracking is that the measurements are
within a pre-defined accuracy range even when the fundamental frequency of the power system
changes.
Table. 5.2.2 - 19. Frequency tracking effect (FF changes from 6 Hz to 75 Hz).
The measurement error with a fixed 50 Hz sampling frequency
when the frequency changes. The constant current is 5 A, the
frequency sweep is from 6 Hz to 75 Hz.
The measurement error with frequency tracking when the
frequency changes. The constant current is 5 A, the
frequency sweep is from 6 Hz to 75 Hz.
As the figures above show, the sampling frequency has a major effect on the relay's measurement
accuracy. If the sampling is not tracked to the system frequency, for example a 10 Hz difference
between the measured and the set system frequency can give a measurement error of over 5 %. The
figures also show that when the frequency is tracked and the sampling is adjusted according to the
detected system frequency, the measurement accuracy has an approximate error of 0.1...- 0.2 % error
in the whole frequency range.
A
AQ
Q-V211
-V211
Instruction manual
Version: 2.04
65