Formation Of Measured Quantities - Landis+Gyr E650 Series User Manual

18/84
2.5.4

Formation of measured quantities

Active energy
Reactive energy
© Landis+Gyr
Measured quantity
THD of active energy import
THD of active energy export
THD of active energy (percent)
THD of phase voltages (absolute)
THD of voltage (percent)
THD of phase currents (absolute)
THD of current (percent)
* Only if U1 is present.
By scanning the mean values of active power P, and in combi-meters also
reactive power Q every second, energy components are produced (Ws or
vars) at fixed intervals (every second) and with varying energy magnitudes
or demand. These energy components are scaled by the microprocessor
corresponding to the meter constant and are then available as measured
quantities for selection of the measured values. The measured values are
fed directly to the following registers to record the energy and the maximum
demand (in combi-meters also of minimum power factor).
The active energy in the individual phases ±A1, ±A2 and ±A3 are formed
directly from the mean values of active power P1, P2 and P3.
By summating the mean values of active energy A1, A2 and A3 the
microprocessor calculates the total active energy import +A or the total
active energy export -A.
Mean values
per second
± A1

±A 2
±A 3
Figure 8. Total active energy
The reactive energy values of the individual phases ±R1, ±R2 and ±R3 are
obtained in the combi-meters directly from the mean values of reactive
power Q1, Q2 and Q3. The reactive energy can therefore also be
calculated vectorially (see 1.5.2).
By summating the mean values of reactive energy R1, R2 and R3, the
microprocessor calculates the total positive reactive energy +R or the total
negative reactive energy -R.
Mean values
per second
± R1

±R 2
±R 3
Figure 9. Total reactive energy
+THD
A
-THD
A
THD [%]
A
THD
U
THD [%]
U
THD
I
THD [%]
I
Measured quantities
+A (Import)
-A (Export)
Measured quantities
+R
-R
D000030108 en m – E650 Series 3 – ZMD300AT/CT – User Manual
Device description
ZMD300
Sum
Sum
Sum
Phase 1, 2, 3
Sum
Phase 1, 2, 3
Sum