Electrex X3M, Руководство пользователя

Страница: 56 / 152

Pag. 56 di 152
1
2
sin ) (
2
cos ) (
2
) (
100
2
1
0
3
2
1
0
3
1
0
2
3
3
−
⎪⎭
⎪
⎬
⎫
⎪⎩
⎪
⎨
⎧
⎥
⎦
⎤
⎢
⎣
⎡
⎟
⎠
⎞
⎜
⎝
⎛
+
⎥
⎦
⎤
⎢
⎣
⎡
⎟
⎠
⎞
⎜
⎝
⎛
=
∑ ∑
∑
−
=
−
=
−
=
N
n
N
n
N
n
I
N
n
n I
N
n
n I
N
n I
THD
π π
Mean phase-phase Voltage
∆
U
3
31 23 12
U U U
U
+ +
=
∆
Average THD of the Phase to phase Voltages:
∆
U
THD
3
31 23 12
U U U
U
THD THD THD
THD
+ +
=
∆
Three phase current:
Σ
I
3
∆
Σ
Σ
=
U
S
I
Average THD of the phase Currents:
Σ
I
THD
3
3 2 1
I I I
I
THD THD THD
THD
+ +
=
Σ
Three phase Active Power:
Σ
P
( ) ( ) ( ) ( )
⎥
⎦
⎤
⎢
⎣
⎡
− =
∑ ∑
−
=
−
=
Σ
1
0
1
0
3 23 1 12
1
M
n
M
n
n I n U n I n U
M
P
Three phase reactive Power:
Σ
Q
( ) ( ) ( ) ( )
⎥
⎦
⎤
⎢
⎣
⎡
+ − + =
∑ ∑
−
=
−
=
Σ
n I M n U n I M n U
M
Q
M
n
M
n
3
1
0
23 1
1
0
12
4 4
1
Three phase apparent Power:
Σ
S
2 2
Σ Σ Σ
+ =
Q P S
Three phase Power Factor:
Σ
λ
( )
Σ
Σ
Σ
Σ
=
Q sign
S
P
λ
where
sign
(
x
) is equal to 1 with
x
> 0, to -1 with
x
< 0.