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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UNCERTAINTY OF MEASUREMENT OF ANALOGUE PRESSURE GAUGE

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SOURCE OF UNCERTAINTY OF PRESSURE GAUGE

  1. Repeatability of the unit under test.
  2. Resolution of UUT
  3. Expanded Uncertainty of Master Instrument
  4. Hysteresis Error
  5. Drift of the Master Instrument\
  6. Uncorrected Error of Master Instrument



  Calibration Result

 

 1.0  Repeatability of the instrument (U1)

Uncertainty from the repeatability  = 0.05774 bar
2.0  Resolution of UUT (U2)
        Resolution of UUT  = 1 bar
     Uncertainty from the resolution of the UUT =  
    
     =(1/5)/sqrt (3)
                                         =0.1154700 bar                              
 3.0  Uncertainty of Master Instrument (U3)

Expanded Uncertainty of Master Instrument  = 0.025 % FSD

Uncertainty of Master Instrument =

                                                                                                                        =((0.025*40)/100)

                                                 = 0.01

                                                                  =0.01/2

                                                                  =0.005 bar

4.0 Hysteresis Error (U4)

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Uncertainty of Hysteresis error of Instrument from the upward and downward direction = 

                                        = 0.00 bar
5.0  Uncertainty of Master Instrument Drift (U5)

Uncertainty from the Drift of Master Instrument  =


=(0.01/3)/sqrt (3)

                              =0.0019245 bar

 6.0  Uncorrected Error of Master Instrument (U6)

Uncorrected Error =  Maximum error found in the calibration  Certificate 


Uncertainty of uncorrected error of Master  =

        

=


                            = (0.009 /2 )/sqrt(3)

                 = 0.002598 bar


Combined Uncertainty (uc(x)) =                                               

                                             

                           =√(0.0577350²+0.11547²+0.005²+0.00²+0.002598²+0.00192²)


                           =0.1292

Expanded Uncertainty (ue(x)) (±) =  (uc(x)) *k

The statement of uncertainty is reported with a coverage factor of k=2, which indicates approximate 95% confidence 
                                                  
                                                    = 0.1292*2

                                                    = 0.2584


                              =   Significant figure rounding (0.2584)


                
                              =0.26 bar





 

             
      










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