Iskra MC320 - Frequency; Energy; MD Values; THD - Total Harmonic Distortion

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MEASUREMENTS
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44 Measuringcentres
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MC320,MC330,MC350&MC350H‐User’sManua
l
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Powerangle represents angle between first voltage harmonic andfirstcurrentharmonicforeachindividual
phase.Totalpowerangleiscalculatedfromtotalactiveandreactivepower(seeequationforTotalpowerangle,
chapterEquationsonpage72).Apositivesignshowsinductiveload,andanegativesignshowscapacitiveload.
Frequency  
Networkfrequencyiscalculatedfromtimeperiodsofmeasuredvoltage.
MainmenuMeasurementsPresentvaluesFrequencyOK
Energy  
Twowaysofenergydisplayareavailable:byindividualmetersandbytariffsforeachmeterseparately.Ata
displayofmeterenergybytariffs,thesumintheupperlinedependsonthetariffssetinthemeter.
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MainmenuMeasurementsPresentvaluesEnergyOK
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MDvalues  
DisplayofMDvalues.
MainmenuMeasurementsPresentvaluesMDvaluesOK
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THD‐Totalharmonicdistortion  
THDiscalculatedforphasecurrents,phaseandphase−to−phasevoltagesandisexpressedaspercentofhigh
harmoniccomponentsregardingRMSvalueorrelativetofirstharmonic.
Instrumentusesmeasuringtechniqueofrealeffective(rms)valuethatassuresexactmeasurementswiththe
presenceofhighharmonicsupto32ndharmonic.
MainmenuMeasurementsPresentvaluesTHDOK
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Customizedscreens  
Adisplayofcustomizedscreensdependsonsettings.SeechapterSettingsofcustomizedscreensonpage29.
MainmenuMeasurementsPresentvaluesCustomOK
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Overview  
Itcombinesseveralmeasurementsoneachdisplayasthefollowingscreensaredisplayed:
ExplanationofmeasurementsforMC330atconnectionmode4u:
SCREEN1:
Currentphasemeasurements Currentphasemeasurements
U
AveragevoltageU

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V P TotalactivepowerP
t
W
1 PhasevoltageU
1
V P1 ActivepowerP
1
W
2 PhasevoltageU
2
V P2 ActivepowerP
2
W
3 PhasevoltageU
3
V P3 ActivepowerP
3
W
I
AveragecurrentI

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A Q TotalreactivepowerQ
t
 var
1 CurrentI
1
 A Q1 Reactivepower
Q
1
var
2 CurrentI
2
 A Q2 Reactivepower
Q
1
var
3 CurrentI
3
 A Q3 Reactivepower
Q
1
var
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