XITRON XT2640 - Power Factor Measurement Specifications; PF Measurement Accuracy Table

XT2640OperatingManual 13July2016 Page178of187
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28.5 POWERFACTORMEASUREMENTSPECIFICATIONS
28.5.1 PFMEASUREMENT ACCURACY TABLE
AddrelevanterrorsfromthetablebelowforthemaximumerrorinPFmeasurements.ForPF
FUND
applyonlytheBaseFloorand
PhaseErrors.
Note:
DCPFis1.0bydefinitionandhasnoerror;thetablebelowappliestoAC,AC+DCandFUNDPFresults.
Specification
Channel
Type
OptionH OptionDHIRange OptionDLORange OptionXHIRange OptionXLORange
BaseFloorError
ApplytoallPFresults
L
(56µA/A
AC+DC
)+
(45µV/V
AC+DC
)
(38µA/A
AC+DC
)+
(45µV/V
AC+DC
)
(250nA/A
AC+DC
)+
(45µV/V
AC+DC
)
(6µA/A
AC+DC
)+
(45µV/V
AC+DC
)
(0.15µA/A
AC+DC
)+
(45µV/V
AC+DC
)
A
(56µA/A
AC+DC
)+
(450µV/V
AC+DC
)
(38µA/A
AC+DC
)+
(450µV/V
AC+DC
)
(250nA/A
AC+DC
)+
(450µV/V
AC+DC
)
(6µA/A
AC+DC
)+
(450µV/V
AC+DC
)
(0.15µA/A
AC+DC
)+
(450µV/V
AC+DC
)
SorW
(225µA/A
AC+DC
)+
(1.8mV/V
AC+DC
)
(150µA/A
AC+DC
)+
(1.8mV/V
AC+DC
)
(1µA/A
AC+DC
)+
(1.8mV/V
AC+DC
)
(23µA/A
AC+DC
)+
(1.8mV/V
AC+DC
)
(0.6µA/A
AC+DC
)+
(1.8mV/V
AC+DC
)
ACFloorError
ApplytoallPFresultsusingvoltageand
currentACFloorErrorfromprevious
tables,thiserroralwayscausesa
reducedPFreading
All ‐PF
RDG
*((CurrentACFloorError/A
RDG
)+(VoltageACFloorError/V
RDG
))
DCFloorError
ApplytoAC+DCPFresultafter
multiplyingby(1‐PF)
L
(0.23mA/A
AC+DC
)+
(0.1mV/V
AC+DC
)
(0.15mA/A
AC+DC
)+
(0.1mV/V
AC+DC
)
(1µA/A
AC+DC
)+
(0.1mV/V
AC+DC
)
(40µA/A
AC+DC
)+
(0.1mV/V
AC+DC
)
(5µA/A
AC+DC
)+
(0.1mV/V
AC+DC
)
A
(0.23mA/A
AC+DC
)+
(1mV/V
AC+DC
)
(0.15mA/A
AC+DC
)+
(1mV/V
AC+DC
)
(1µA/A
AC+DC
)+
(1mV/V
AC+DC
)
(40µA/A
AC+DC
)+
(1mV/V
AC+DC
)
(5µA/A
AC+DC
)+
(1mV/V
AC+DC
)
S
(0.45mA/A
AC+DC
)+
(3mV/V
AC+DC
)
(0.3mA/A
AC+DC
)+
(3mV/V
AC+DC
)
(2µA/A
AC+DC
)+
(3mV/V
AC+DC
)
(80µA/A
AC+DC
)+
(3mV/V
AC+DC
)
(6µA/A
AC+DC
)+
(3mV/V
AC+DC
)
W
(0.68mA/A
AC+DC
)+
(5mV/V
AC+DC
)
(0.45mA/A
AC+DC
)+
(5mV/V
AC+DC
)
(3µA/A
AC+DC
)+
(5mV/V
AC+DC
)
(120µA/A
AC+DC
)+
(5mV/V
AC+DC
)
(8µA/A
AC+DC
)+
(5mV/V
AC+DC
)
PhaseError
ApplytoallPFresults
S,AorL
(PF
FUND
‐cos(cos
‐1
(PF
FUND
)± 0.015°*F))
Alternately,asaworstcase(atPF=0)thiscanexpressedasF*0.00028
W
(PF
FUND
‐cos(cos
‐1
(PF
FUND
)±0.007°*F))
Alternatel
y
,asaworstcase
(
atPF=0
)
thiscanex
p
ressedasF*0.00013
28.5.1.1 EXAMPLES
Example1
ForanADchannel(HIrange)themaximumerrorofameasurementoftheAC+DCPFofa240V,5Arms,PF=0.5(causedbyphase
shift)signalat50Hzisaworstcaseof±0.000029ascalculatedby:
FloorErrors:
BaseFloor=(38µA/5A)+(450µV/240V)=±0.000009475
ACFloor=‐0.5*(((1.5µA/5A)/5A)+((100µV/240V)/240V))=‐0.5*(0.00000006+0.0000000017)=‐0.00000003
DCFloor=(1‐0.5)*((0.15mA/5A)+(1mV/240V))=±0.00001708
TotalFloorErrors=±0.000018
PhaseErrors:
(0.5‐cos(cos
‐1
(0.5)+0.015°*0.05))=(0.5‐cos(60°+0.015°*0.05))=±0.000011
TotalPhaseErrors=±0.000011
Example2
AsExample1butwherethePF=0.5iscausedbyloaddistortioninsteadofphaseshift,themaximumerrorofthemeasurementofthe
AC+DCPFisaworstcaseof±0.000018ascalculatedby:
FloorErrors:
BaseFloor=(38µA/5A)+(450µV/240V)=±0.000009475
ACFloor=‐0.5*(((1.5µA/5A)/5A)+((100µV/240V)/240V))=‐0.5*(0.00000006+0.0000000017)=‐0.00000003
DCFloor=(1‐0.5)*((0.15mA/5A)+(1mV/240V))=±0.00001708
TotalFloorErrors=±0.000018
PhaseErrors:
PF
FUND
=1.0sinceloadhasnophaseshiftonlydistortion.
(1‐cos(cos
‐1
(1)+0.015°*0.05))=(1‐cos(0°+0.015°*0.05))=0
TotalPhaseErrors=0
Example3
ForaWDchannel(HIrange)themaximumerrorofameasurementoftheACPFofa100V,5Arms,PF=0.01(causedbyphaseshift)
signalat50kHzisaworstcaseof±0.0062ascalculatedby:
FloorErrors:
BaseFloor=(150µA/5A)+(1.8mV/100V)=±0.000048
ACFloor=‐0.01*(((250µA/5A)/5A)+((1.1mV/100V)/100V))=‐0.01*(0.00001+0.0000011)=‐0.0000001
TotalFloorErrors=±0.0000481
PhaseErrors:
(0.01‐cos(cos
‐1
(0.01)+0.007°*50))=(0.01‐cos(89.427°+0.007°*50))=0.006152