The
frequency
of the phases is determined by a zero crossing detection of the sampled
signals and calculating from the frequency.
The
apparent power S
is a combination of
active power P
and
reactive power Q
. It is cal-
culated from the product of effective current
I
eff
and
effective voltage U
eff
. With the appa-
rent power you get the total power of a power grid.
Reactive power Q
means a load in the power grid, which opposes the current flow from
the producer to the consumer. The reactive power is the product of current and voltage at
a reactance. Reactive power forms to all devices that are connected to AC networks. With
voltage supplied any electrical device generates an electromagnetic field. By alternating
voltage, the magnetic field is regularly built and removed. During the removement the
energy gained in the field is fed back into the power grid and results in a higher resist-
ance to the applied current flow.
The
active power P
is the effectively used power. This is the part without phase shift
between voltage and current and refers to a resistive load. In an AC voltage, the active
power is calculated by multiplying the effective values of current and voltage.
In real networks energy consumers / producers typically are not purely ohmic. There is a
phase shift between current and voltage. The
cos
j
is a measure of the phase shift
between current and voltage of the basic frequency of the corresponding phase. The
total
cos
j
is calculated by dividing
total active power P
and
total apparent power S
.
Harmonics are oscillations of the voltages and currents, whose frequency is an integer
multiple of the basic frequency. The 1. harmonic is the basic frequency or mains fre-
quency, nominally 50Hz or 60Hz. The level of harmonics is a measure for the network
quality. Harmonics or harmonic oscillations are caused by equipment with non-linear
characteristics such as transformers, fluorescent lamps and power electronic equipment
such as rectifiers and thyristors. The non-sinus-shaped currents of these consumers
cause the net interference voltages, which distorts the nominal line voltage. During para-
metrization you can specify the level of the harmonic. With this frequency the
‘harmonic’
current and voltage values are filtered.
3.27.4
Connection
CAUTION!
Connection and module exchange only without power!
–
Before you start to work on at the module for installation or mainte-
nance, you have to disconnect it from the main power source, i.e. the
power line is to be switched off (possibly remove fuses)!
–
The electronic module may only be replaced on power off!
–
Only properly qualified electrical staff is allowed to install, connect
and/or modify electrical equipment!
–
Please adhere to the national rules and regulations of the location
and/or country where the units are installed (installation, safety pre-
cautions, EMC ...).
Determine frequency
Apparent power
Reactive power
Active power
Calculation of the power
factor cos
j
(phi)
Harmonics
Please note
VIPA System SLIO
Analog Input
031-1PA00 - AI1x 3Ph 230/400V 1A > Connection
HB300 | SM-AIO | | en | 17-05
312