Iskra MC320 User Manual

APPENDIXE:CALCULATIONS&EQUATIONS

Measuringcentres
–
MC320,MC330,MC350&MC350H ‐ User’sManua
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73

Current

N
=
i
I
2
n
N
1=n
RMS


Phasecurrent
N‐128samplesinaperiod(upto65Hz)
N‐128samplesinmoreperiods(above65Hz)

N
iii
=
2
n3n2n1
N
1=n
n
I



Neutralcurrent
i‐nsampleofphasecurrent(1,2or3)
N‐128samplesinaperiod(upto65Hz)
Power





N
1n
fnfnf
iu
N
1
P

Activepowerbyphases
N‐anumberofperiods
n‐indexofsampleinaperiod
f‐phasedesignation
321t
PPPP 

Totalactivepower
t‐totalpower
1,2,3‐phasedesignation



 
1360801
11800





f
f
f
SignQ
SignQ
SignQ
Reactivepowersign
Q
f
‐reactivepower(byphases)
φ‐powerangle
fff
IUS 

Apparentpowerbyphases
U
f
‐phasevoltage
I
f
‐phasecurrent
321t
SSSS 

Totalapparentpower
S
f
‐apparentpowerbyphases

2
f
2
fff
PSSignQQ 

Reactivepowerbyphases
S
f
‐apparentpowerbyphases
P
f
‐activepowerbyphases
321t
QQQQ 

Totalreactivepower
Q
f
‐reactivepowerbyphases

 

99,179,180
,2arctan
s
tts
QP


Totalpowerangle
P
t
‐totalactivepower
S
t
‐totalapparentpower
t
t
t
S
P
PF 

3phasepowerfactor
P
t
‐phaseactivepower
S
t
‐phaseapparentpower
f
f
f
S
P
PF 

Powerfactorbyphases
P
f
‐phaseactivepower
S
f
‐phaseapparentpower


Iskra MC320 Specifications

General

Frequency	50 Hz
Accuracy class	1
Test Voltage	4 kV
Voltage	3 x 230 V / 400 V
Communication	RS485
Standards	IEC 62053-21, IEC 62052-11
Display	LCD