5 Calculation formulas
33
5 Calculation formulas
5.1
One-phase network
One-phase network
Parameter
Method of calculation
Name
Designa-
tion
Unit
Voltage (True RMS)
U
A
V
𝑈
𝐴
= √
1
𝑀
∑ 𝑈
𝑖
2
𝑀
𝑖=1
where
U
i
is a subsequent sample of voltage
U
A-N
M
= 2048 for 50 Hz and 60 Hz
Voltage DC component
U
ADC
V
𝑈
𝐴𝐷𝐶
=
1
𝑀
∑ 𝑈
𝑖
𝑀
𝑖=1
where
U
i
is a subsequent sample of voltage
U
A-N
M
= 2048 for 50 Hz and 60 Hz
Frequency
F
Hz
number of full voltage periods
U
A-N
counted during 10-sec period (clock time) divided by the
total duration of full periods
Current (True RMS)
I
A
A
𝐼
𝐴
= √
1
𝑀
∑ 𝐼
𝑖
2
𝑀
𝑖=1
where
I
i
is subsequent sample of current
I
A
M
= 2048 for 50 Hz and 60 Hz
Current constant compo-
nent
I
ADC
A
𝐼
𝐴𝐷𝐶
=
1
𝑀
∑ 𝐼
𝑖
𝑀
𝑖=1
where
I
i
is a subsequent sample of current
I
A
M
= 2048 for 50 Hz and 60 Hz
Active power
P
W
𝑃 =
1
𝑀
∑ 𝑈
𝑖
𝐼
𝑖
𝑀
𝑖=1
where
U
i
is a subsequent sample of voltage
U
A-N
I
i
is a subsequent sample of current
I
A
M
= 2048 for 50 Hz and 60 Hz
Budeanu reactive power
Q
B
var
𝑄
𝐵
= ∑ 𝑈
ℎ
𝐼
ℎ
sin 𝜑
ℎ
40
ℎ=1
where
U
h
is
h
-th harmonic of voltage
U
A-N
I
h
jest
h
-th harmonic of current
I
A
h
is
h
-th angle between harmonic
U
h
and
I
h
Reactive power of funda-
mental component
Q
1
var
𝑄
1
= 𝑈
1
𝐼
1
sin 𝜑
1
where U
1
is fundamental component of voltage
U
A-N
I
1
is fundamental component of current
I
A
1
is angle between fundamental components
U
1
and
I
1
Apparent power
S
VA
𝑆 = 𝑈
𝐴𝑅𝑀𝑆
𝐼
𝐴𝑅𝑀𝑆
Apparent distortion
power
S
N
VA
𝑆
𝑁
= √𝑆
2
− (𝑈
1
𝐼
1
)
2
Budeanu distortion power
D
B
var
𝐷
𝐵
= √𝑆
2
− 𝑃
2
− 𝑄
𝐵
2
Power Factor
PF
-
𝑃𝐹 =
𝑃
𝑆
If PF < 0, then the load is of a generator type
If PF > 0, then the load is of a receiver type
Summary of Contents for PQM-700
Page 85: ...85 Notes...