Alstom iSTAT M355, Manual, Page: 149 / 154

User Manual M3x5/EN M/B
iSTAT M3x5
Page 147
Power
 


  
N
1 n
fn fn f
i u
N
1
P
Active power by phases
N − a number of periods
n − index of sample in a period
f − phase designation
3 2 1 t
P P P P
  
Total active power
t − total power
1, 2, 3 − phase designation
 
 
 
 
 
1 SignQ 360 80 1
1 SignQ 180 0
SignQ
f
f
f
        
        

Reactive power sign
Q
f
− reactive power (by phases)
φ − power angle
f f f
I U S
 
Apparent power by phases
U
f
− phase voltage
I
f
− phase current
3 2 1 t
S S S S
  
Total apparent power
S
f
− apparent power by phases
 
2
f
2
f
f f
P S SignQ Q
   
Reactive power by phases
S
f
− apparent power by phases
P
f
− active power by phases
 
 


  
N
N n
f
n
f f
i u
N
Q
4 /
1

n
1
Reactive power by phases (displacement
method)
N − a number of samples in a period
n − sample number (0 ≤ n ≤ N)
f − phase designation
3 2 1 t
Q Q Q Q
  
Total reactive power
Q
f
− reactive power by phases
 
 
   

99 , 179 , 180
, 2 arctan
s
t t s
Q P


Total power angle
P
t
− total active power
S
t
− total apparent power
t
t
t
S
P
PF

Distortion factor
P − total active power
S − total apparent power
f
f
f
S
P
PF

Distortion factor
P
t
− phase active power
S
t
− phase apparent power