Landis+Gyr E650 Series User Manual page 20

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Direction of rotating
field
Total harmonic
distortion
© Landis+Gyr AG
Fig. 1.15 Phase angle case 1
Case 2: The voltage angles are displayed as in case 1. The angles of the
currents are displayed, however, with reference to the associated phase
voltage and can have values between -180° and +180°.
Fig. 1.16 Phase angle case 2
The direction of the rotating field is calculated by the microprocessor based
on the phase angle of the 3 voltages. If the direction of rotation corres-
ponds to that specified by the parameterisation, the phase voltage indica-
tions L1, L2 and L3 are continuously lit. Otherwise they flash every second.
The measuring system produces information about the total harmonic dis-
tortion of the active energy.
For that purpose, the voltages are fed through notch filters, which remove
the fundamental wave.
+A
+THD = +A - (+A
-A
-THD = -A - (-A
Fig. 1.17 Calculation of total harmonic distortion
In addition, the following absolute and relative THD values available:

THD of active energy (relative to the nominal active energy)

THD of phase voltages (absolute)

THD of voltage (relative to the nominal voltage)

THD of phase currents (absolute)

THD of phase current (relative to the nominal current)
D000030110 d – E650 Series 3 (ZMD400AT/CT, ZFD400AT/CT) – User Manual
)
A fundamental
)
A fundamental
Description of Unit
+THD
A
-THD
A