Lab report 04

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EAST WEST UNIVERSITY DEPARTMENT OF EEE Course code: EEE 201 Course name: Electrical circuit ΙΙ Lab report Experiment no: 04 Experiment name: Power factor improvement by parallel capacitor. Student name: B. M. ADNAN Id: 2011-1-80-020 Section: 02 Date of performance: 28-02-12 Date of submission: 13-03-12

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EEE lab report of Eastwest university Bangladesh.. and praise.

Transcript of Lab report 04

Page 1: Lab report 04

EAST WEST UNIVERSITYDEPARTMENT OF EEE

Course code: EEE 201Course name: Electrical circuit ΙΙ

Lab reportExperiment no: 04

Experiment name: Power factor improvement by parallel capacitor.

Student name: B. M. ADNANId: 2011-1-80-020

Section: 02

Date of performance: 28-02-12Date of submission: 13-03-12

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OBJECTIVE: The main aim of this experiment is to provide us more understanding of practical implementation of parallel capacitor bank in improving power factor of an inductive load.

CIRCUIT DIAGRAM:

Figure: circuit diagram to study PFI.

EXPERIMENTAL DATA

R1 R2 V L f ω102.1Ω 100Ω 5<0V 100mH 1KHz 6283.2rad/sec

ANSWER TO THE LAB-REPORT QUESTIONS:

1. Here Inductance, L = 100mH = j628.23 Ω Capacitance, C = 1 microF = -j159.15 Ω So, Impedance Z = 102.1 + {(100 + j628.32) ׀ ׀ (-j159.15)} = 239.22<-61.78 Ω We know that, I = V/ Z = 5< 0/239.22<-61.78

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= 0.021<61.78 A Now phase angle for voltage, θv = 0 And phase angle for current, θi = 61.78 So, power factor, Pf cos (θv - θi) = cos(- 61.78) = 0.47

Again, L = j628.32 Ω C = -j106.103 Ω (for C = 1.5microF) So, Impedance, Z = 102.1 + {(100 + j628.32) ׀ ׀ (-j106.103) = 165.39 <-50.106 Ω So, I = V/Z = 5/ 165.39<-50.106 = 0.030<50.106 Ω So, power factor Pf, cos (θv - θi) = cos(0 – 50.106) = 0.64

COMPARING

Capacitor values Calculated values Experimental values1microF 0.47 0.64

1.5microF 0.64 0.73

Calculated power factor values capacitors

Values of C (microF) Pf = cos(Δθ)0.5 0.410.8 0.450.9 0.491.0 0.471.2 0.621.5 0.642.0 0.712.5 0.803.0 0.853.5 0.894.0 0.924.5 0.955.0 0.97

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Comment: 1. Here we have bit difference among calculated and experimental values. But they are negligible.2. The calculated values of pf used as pf2 in MATLAB to bring the numeric terms in graphical terms

2.

Measured power factor values for capacitors

Values of C (microF)

Δt (ms) Δθ (degree) Pf = cos(Δθ)

0.5 0.18 64.8 0.430.8 0.16 57.6 0.540.9 0.15 54 0.591.0 0.14 50.4 0.641.2 0.13 46.8 0.691.5 0.12 43.2 0.732.0 0.11 39.6 0.772.5 0.10 36 0.813.0 0.08 28.8 0.883.5 0.07 21.6 0.934.0 0.06 18 0.954.5 0.04 14.4 0.985.0 0.02 7.2 0.99

Comment: 1.Here the measured pf values are almost same with the calculated values. 2. The measured values of pf used as pf1 in MATLAB to bring the numeric terms in graphical terms.

3. The graphical diagram which I got from MATLAB by using experimental and calculated data as well as data table is attached with the report. MATLAB CODE: clc c= [0.5 0.8 0.9 1.0 1.2 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0] pf1= [0.43 0.54 0.59 0.64 0.69 0.73 0.77 0.81 0.88 0.93 0.95 0.98 0.99] pf2= [0.41 0.45 0.49 0.47 0.62 0.64 0.75 0.80 0.85 0.89 0.92 0.95 0.97] Plot (c, pf1, c, pf2)

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0.5 1 1.5 2 2.5 3 3.5 4 4.5 50.4

0.5

0.6

0.7

0.8

0.9

1

c

pf1,pf2

Figure: c vs. pf1 and c vs. pf2 graph.

Comment: The graph getting from MATLAB by using measured and calculated data are very near each other.

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DISCUSSIONS: In this experiment we learnt about how to calculate power factor by using oscilloscope as well as how to improve power factor by using parallel capacitor.

1. The main view of improving power factor is to less loss of power. By which we can make our electrical equipments more efficient.

2. Here we used parallel capacitance for improving power factor. Because it’s the best way.

3. We can use the capacitor series also. But that will create a problem. If we use capacitor in series then there will be a voltage drop. And we know that electronics equipments can fused when we connect it with low voltage. So we do not use capacitor in series.

4. Again we know that for capacitance current will lead voltage and at the time of inductance current will lags voltage.

5. Power factor cannot increase more than 1and cannot lower than 0.

6. For totally resistive circuit power factor is 1. For RL circuit power factor is lower. And for RC circuit power factor is higher than RL circuit.

7. When we increase the value of capacitance the value of power factor will increase up to 1 or near to 1. But after a certain level power factor will not increase.