Appendix E EN50160 Evaluation and Recording
EM720 Power Quality and Revenue Meter
213
distortion factor (THD) over a period of 10 minutes under
normal operating conditions.
Interharmonic voltages are evaluated by instrumentation
complying with IEC 61000-4-7. All calculations are made
relative to the nominal voltage.
The highest harmonic order for evaluating individual
interharmonic voltages and interharmonic THD can be
selected in the meter in the range of 25 to 50 via the
EN50160 Advanced setup.
Interharmonic voltages are not evaluated if the supply
voltage crosses a voltage tolerance limit (
±
15% Un).
Target Values
The EN50160 does not provide target limits for interharmonic
voltages. The ranges of interharmonic voltages selected in
the EM720 are:
•
Interharmonic THD
≤
2
% for 95% of a week
•
Individual interharmonic voltages shall be less than or
equal to the values given in the following table for
95% of a week.
Interharmonic order
Relative Voltage
2 0.2
3-15 1.0
16-25 0.5
You can change the compliance limit for the interharmonic
THD via the EN50160 PQ Recorder setup. The individual
interharmonic voltage limits can be changed via the EN50160
Harmonics setup.
Mains Signaling Voltage
This characteristic defines the magnitude of the signal
voltages used in some countries for signal transmission over
public supply networks. These may include ripple control
signals in a frequency range from 100 HZ to 3 kHz, and
carrier wave communications signals in a frequency range
from 3 kHz to 148.5 kHz.
The EM720 can evaluate ripple control signaling voltages in a
frequency range from 100 Hz to 3 kHz.
Method of Evaluation
Since evaluating signal voltages is not commonly used, this
feature is normally disabled in your meter. You can enable
evaluation of signaling voltages via the EN50160 Advanced
Setup.
The EM720 evaluates up to four ripple control frequencies.
You can select the required signaling frequencies via the
EN50160 Advanced Setup.
The basic measurement is the magnitude of the signaling
voltage over a period of 3 seconds under normal operating
conditions.
