Measurements
User’sManual 29
Note
For 3b and 3u connection mode, only phase to phase voltages are
measured. Because of that factor √3 is applied to calculation of quality
considering nominal phase voltage.
For 4u connection mode measurements support is same as for 1b.
5.4 Explanation of basic concepts
Sample factor − M
V
A meter measures all primary quantities with sample frequency which cannot exceed a certain
number of samples in a time period. Based on these limitations (65Hz·128 samples) a sample
factor is calculated. A sample factor (M
V
), depending on frequency of a measured signal, defines
a number of periods for a measurement calculation and thus a number of harmonics considered
in THD calculations.
Average interval − M
P
Due to readability of measurements from communication, an Average interval (M
P
) is calculated
with regard to the measured signal frequency. The Average interval (see chapter Average
interval on page 18) defines refresh rate of displayed measurements based on a sampling factor.
Power and energy flow
Figures below show a flow of active power, reactive power and energy for 4u connection.
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