KVAR RATING CALCULATOR,CAPACITOR BANK SIZE CALCULATION

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  Determination of Required Capacitor Rating by measurement 3 Methods are used. 1. Measurement with current and power factor 2.Measurement with recording of Active and Reactive power. 3.Measurement by Reading Meters . 1 . Measurement with Current and power factor The active power P is calculate from the measured voltage V ,apparent current Is and Power Factor P=√3*Voltage*apparent Current*cosψ *10^-3 If the desired power factor cosψ has been specified, the capacitor power rating can be calculate from the following formula: Qc = P. (tan ψactual - tanψ desired) Let's See the Example Measured Apparent Current Is : 248 Amps Power Factor cos ψ1 = 0.86 Desired Cos ψ2 = 0.92 Voltage V :397 V p=√3 * 397 * 248 * 0.86 * 103 P = 146.6 KW Qc= P. (tanψ actual - tanψ desired) = 146.6(0.59 - 0.42) = 24.9 KVAR
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CMC VALUE CALCULATION FROM THE SCOPE OF ACCREDITATION

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DC CURRENT CMC CALCULATION

CMC=Calibration measurement capability

Calibration and Measurement Capability (CMC) is the smallest uncertainty of measurement that a laboratory can achieve within its scope of accreditation when performing more or less routine calibrations of nearly ideal measurement standards or nearly ideal measuring equipment. Calibration and Measurement Capabilities represent expanded uncertainties expressed at approximately the 95 % level of confidence, usually using a coverage factor of k = 2. The actual measurement uncertainty of a specific calibration performed by the laboratory may be greater than the CMC due to the behavior of the customer’s device and to influences from the circumstances of the specific calibration.

Figure below the how the Accredited Scope given the CMC of the DC Current

CMC CALCULATION FROM THE ACCREDITATION SCOPE
CMC From the Scope of Accreditation


Unit Under Test(UUT) instrument  Expanded uncertainty should always is  greater than the CMC


0 µA to 329.999 µA  ---------- 0.12 x 10-3 I +0.011 µA

I=Measured Current Value

Applied Value – The Current that applied from the Master eg Fluke 5522A

Measured Value – The current is measured by the UUT (Unit under Test)

Resolution of UUT = 0.01 µA


Applied Value (Master)

Measured Value        (UUT)

CMC

CMC Value

300 µA

300.02 µA

0.12 x 10-3 I +0.011 µA

 

0.047002  µA

I=300.02 µA

=0.12 x 10-3 *300.02 µA +0.011 µA

=0.00012*300.02+0.011 µA

=0.047002  µA

 EXAMPLE

DC CURRENT CMC VALUE CALCULATION

CMC VALUE CALCULATION
CMC VALUE CALCUALTION OF DC CURRENT

Reference standard of this calculation is based on the Euramet CG-17



 

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