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A.1.2.9 FUNDAMENTAL RMS VALUES (EXCLUDING NEUTRAL – OVER ONE SECOND)
These are calculated from the filtered vector (instantaneous) values. A digital filter made up of six low-pass order 2 infinite
pulse response Butterworth filters and one high-pass order 2 infinite pulse response Butterworth filter is used to extract
the fundamental components.
A.1.2.10 FUNDAMENTAL ANGULAR VALUES (EXCLUDING NEUTRAL – OVER ONE SECOND)
These are calculated from the filtered vector (instantaneous) values. A digital filter made up of six low-pass order 2 infinite
pulse response Butterworth filters and one high-pass order 2 infinite pulse response Butterworth filter is used to extract
the fundamental components. The angular values calculated are those between:
■ Two phase-to-neutral voltages
■ Two line currents
■ Two phase-to-phase voltages
■ One phase-to-neutral voltage and one line current (distribution systems with neutral)
■ One phase-to-phase voltage and one line current (2-wire two-phase distribution systems)
A.1.3 Harmonic Mode
A.1.3.1 HFFT (NEUTRAL INCLUDED EXCEPT FOR UHARM AND VAHARM – OVER 4 CONSECUTIVE
PERIODS EVERY SECOND)
Harmonic bins are calculated by FFT with 16 bit resolution (1024 samples on four cycles) with a rectangular window (see
IEC61000-4-7). From the real parts bk and the imaginary parts ak, the harmonic factor is calculated for each order (j) and
for each phase (i) Vharm[i][j], Uharm[i][j] and Aharm[i][j] with respect to the fundamental and the angles Vph[i][j], Uph[i][j]
and Aph[i][j] with respect to the fundamental. For the neutral-earth voltage and the neutral current, the level of harmonics
is calculated for each order (j) Vharm[3][j] and Aharm[3][j] with respect to the total RMS value (AC+DC) of the complete
signal (the harmonic angles are not calculated).
Note: The calculations are performed sequentially: {V1; A1} then {V2; A2} then {V3; A3} then {UN ; AN} then {U1; U2} and
finally {U3}. In the case of a 2-wire two-phase distribution source, the couple {V1; A1} is replaced by the couple {U1; A1}.
The level in % with respect to the fundamental:
c
k
t
=
100
[% f] ⇔
k
c
4
The level in % with respect to the total RMS value:
[% r] ⇔
The angle with respect to the fundamental in degrees:
a
k
ϕ
=
arctan
[°] ⇔
k
b
k
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−
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