HT Italia SOLAR300, User Manual

Page: 155 / 160

SOLAR300 - SOLAR300N
EN - 153
It shall be noted that the expression of the phase Reactive Power with no sine waveforms,
would be wrong. To understand this, it may be useful to consider that both the presence of
harmonics and the presence of reactive power produce, among other effects, an increase
of line power losses due to the increased current RMS value. With the above given relation
the increasing of power losses due to harmonics is added to that introduced by the
presence of reactive power. In effect, even if the two phenomena contribute together to the
increase of power losses in line, it is not true generally that these causes of power losses
are in phase between each other and therefore that can be summed mathematically.
The above given relation is justified by the relative simplicity of its calculation and by the
relative discrepancy between the value obtained using this relation and the true value.
It shall also be noted, how, in case of an electric installation with harmonics, another
parameter called distorted Power Factor (Cosphi) is defined. In practice, this parameter
represents the theoretical limit value that can be reached for Power Factor if all the
harmonics could be eliminated from the electric installation.
10.10.1. Conventions on powers and power factors
As for the recognition of the type of reactive power, of the type of power factor and of the
direction of the active power, the below conventions must be applied. The stated angles
are those of phase-displacement of the current compared to the voltage (for example, in
the first panel the current is in advance from 0° to 90° compared to the voltage):
Equipment under test = Inductive Generator
 
Equipment under test = Capacitive Load
90°
180°
P
act
+ = 0
Pfc+ = -1
Pfi+ = -1
P
react
c+ = 0
P
react
i+ = 0
P
act
- = P
act
Pfc - = -1
Pfi - =
Pf
P
react
c- = 0
P
react
i - = P
react
P
act
+ = P
act
Pfc+ = Pf
Pfi+ = -1
P
react
c+ = Q
P
react
i+ = 0
P
act
- = 0
Pfc - = -1
Pfi - = -1
P
react
c- = 0
P
react
i- = 0
0°
P
act
+ = 0
Pfc+ = -1
Pfi+ = -1
P
react
c+ = 0
P
react
i+ = 0
P
act
- = P
act
Pfc - = Pf
Pfi - = -1
P
react
c- = P
react
P
react
i - = 0
P
act
+ = P
act
Pfc+ = -1
Pfi+ =
Pf
P
react
c+ = 0
P
react
i+ = P
react
P
act
- = 0
Pfc - = -1
Pfi - = -1
P
react
c- = 0
P
react
i - = 0
270°
Equipment under test = Capacitive Generator
 
Equipment under test = Inductive Load
where:
Symbol Description Remarks
Pact+ Value of the active power +
Positive parameter
(user)
Pfc+ Capacitive power
Pfi+ Inductive power
Value of the capacitive reactive power +
Value of the inductive reactive power +
Pact- Value of the active power -
Negative parameter
(generator)
Pfc- Capacitive power factor -
Pfi- Inductive power factor -
Preactc- Value of the capacitive reactive power -
Preacti- Value of the inductive reactive power -
Value Description