ZES ZIMMER LMG450, User Manual

Page: 115 / 306

Z E S ZIMMER Electronic Systems GmbH Chapter 7
115
Voltage and current
true root mean square:
Utrms
T
u t dt
t
T
=
=
∫
1
2
0
( ) Itrms
T
i t dt
t
T
=
=
∫
1
2
0
( )
total harmonic distortion:
Uthd
U
U
n
n
=






=
∑
1
2
2
40
Ithd
I
I
n
n
=






=
∑
1
2
2
40
The harmonic values ‘I(n)’ and ‘U(n)’ are calculated by using a DFT algorithm.
The values ‘Pmom’, ‘Pst’ and ‘Plt’ are calculated using a flickermeter according to
EN61000-4-15. ‘dc’ and ‘dmax’ are calculated according to EN61000-3-3.
Power
active power:
P
T
u t i t dt
t
T
=
=
∫
1
0
( ) ( )
reactive power:
Q S P
= − 2 2
apparent power:
S Utrms Itrms
=
*
power factor:
λ =
P
S
Impedances
apparent impedance:
Z
Utrms
Itrms
=
active impedance:
Rser
P
Itrms
=
2
reactive impedance:
Xser
Q
Itrms
=
2
7.4 Display of values
For the display of the values you can choose several menues.
7.4.1 Default
For the display of the values we have the same rules like in the normal measuring mode (see
5.4, ‘Display of values’)