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Function Description
WAGO-I/O-SYSTEM 750
750-494 3-Phase Power Measurement Module
Manual
Version 1.2.0
Harmonics Analysis
The I/O module calculates the frequency spectrum for the periodic input signals
and analyzes the fundamental component and the next 40 harmonics for each
phase. This analysis can be conducted on one of the three phases (L1 or L2 or L3).
The I/O module always yields the RMS values for current and voltage of the
fundamental component for the selected phase. The I/O module also provides the
total harmonic distortion (THD) for current and voltage.
From the 40 harmonics, three can be selected and analyzed at the same time. The
RMS value for current and voltage is calculated for each selected harmonic, along
with the harmonic distortion (HD). The harmonics can be freely selected, e.g., 4 –
12 – 19 or 2 – 35 – 40.
Calculating the Power Factors
The power factor
cos phi
is the cosine of the phase angle between voltage and
current for the specific phase. Calculation of the power factor only takes into
account the phase shifting of the fundamental components of voltage and current.
The sign used in front of "cos phi" indicates the following:
•
positive (plus) sign:
Acquisition of active power from the supply
network
•
negative (minus) sign:
Delivery of active power into the supply network
The
power factor PF
is the quotient of the active power (P) and apparent power
(S) and takes the entire spectrum into account, i.e., the fundamental component
and the harmonics.
PF = P / S
•
positive (plus) sign:
Acquisition of active power from the supply
network
•
negative (minus) sign:
Delivery of active power into the supply network
The
power factor LF
is the quotient from the amount for active power (P) and
apparent power (S), multiplied by the sign for reactive power (Q) and takes the
entire spectrum into account, i.e., the fundamental component and the harmonics:
LF = sign Q
·
|P| / S
•
positive (plus) sign:
positive reactive power
•
negative (minus) sign:
negative reactive power
