Name
Values
3PH (S)
20.00 MVA
3PH (P)
17.32 MW
3PH (Q)
0.00 Mvar
3PH Tan
0.00
3PH Cos
0.87
5.2.4. Frequency tracking and scaling
Measurement sampling can be set to the frequency tracking mode or to the xed user-
de ned frequency sampling mode. The bene t of frequency tracking is that the measurements are
within a pre-de ned accuracy range even when the fundamental frequency of the power system
changes.
Table. 5.2.4. - 42. Frequency tracking effect (FF changes from 6 Hz to 75 Hz).
The measurement error with a xed 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 gures 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
gures 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 % in
the whole frequency range.
AQ-E215
Instruction manual
Version: 2.01
© Arcteq Relays Ltd
64