EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
Laboratory No. 4
Real, Reactive and Apparent Power
Submitted by:
Garcia, Danarie D.
Garcia, Kyle Vincent L.
Geron, Mark Angelo D.
Harina, Mark AngeloH.
Hernandez, Jean Clarence P.
PetE-2101
Bachelor of Science in Petroleum Engineering
20-09878@g.batstate-u.edu.ph
20-02694@g.batstate-u.edu.ph
20-08867@g.batstate-u.edu.ph
20-01873@g.batstate-u.edu.ph
20-04458@g.batstate-u.edu.ph
Engr. Jonas S. De Castro, REE
Lecturer
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
Abstract – Reactive power is electrical energy that is held in the coil and then flows back
to the grid. Ideal coils utilize no electrical energy while producing a substantial electric current.
Real power is the power utilized because of the resistive load, whereas apparent power is the power
that the grid must be able to bear. The unit of real power is watt, while the unit of perceived power
is VA volt ampere. The issue of reactive power is not simply technical, but it also has significant
economic implications. Indeed, a utility firm must construct an infrastructure capable of
transporting visible energy, but only bills for actual electricity. It would be unsustainable if the
disparity was too significant. The power factor is the ratio of real power to perceived power. The
power factor should be as near to one as feasible. The goal of this experiment is to improve a
student's understanding of real, reactive, and apparent power. The purpose of this experiment is to
determine the relationship between the three. To determine the predicted outcomes, the experiment
is carried out in Multisim which includes an AC power supply, ground, wattmeter, electrical wires,
breadboard, inductors, capacitor, and virtual lamp.
INTRODUCTION
The product of a circuit's
The apparent power is the vector sum of
voltage and current without regard for
real and reactive power engineers use the
phase angle is known as apparent
following terms to describe energy flow in a
power, and it is the product of
system (and assigned each of them a different unit
reactive power and true power. The
to differentiate between them):
capital letter S represents apparent
A. Real Power (P) [Unit W]
power, which is measured in Volt-
True power is the actual
Amps (VA).
amount of power used or dissipated in
a circuit, and it is measured in watts
(symbolized by the capital letter P, as
always).
Reactive loads like inductors
and capacitors dissipate zero power,
but the fact that they drop voltage and
current
impression
that
gives
they
watt (symbol: W). However, this unit is
generally reserved for the real power
component.
B. Reactive Power (Q) [Unit VAR]
draw
The unit for all forms of power is the
the
false
do.
This
"phantom power" is known as
reactive power, and it is measured in
Volt-Amps-Reactive (VAR) units
Apparent
power
is
conventionally expressed in volt-amperes
(VA) since it is a simple product of RMS
voltage and RMS current. The unit for
reactive power is given the special name
“VAR”, which stands for volt-amperes
reactive (since power flow not net energy to
the loads, it is sometimes called wattles
power).
rather than watts. The capital letter Q
is the mathematical symbol for
reactive power.
C. Apparent Power (S) [Unit KVA]
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
a. If using offline Multisim measure it using
OBJECTIVES OF THE STUDY
1. Determine
the
real,
the wattmeter.
reactive,
and
b. If using the online version, please
apparent power by measurements.
measure it using the manual computation
2. Compare the measured and calculated
based on the value of the Multisim. Refer
real, reactive, and apparent power for the
to the formula below.
given circuit.
𝑃𝑓 = 𝑍∟𝜃 → 𝑐𝑜𝑠𝜃
3. Determine the impedance of a given
𝑃𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = 𝐸𝑡 𝐼𝑡 𝑐𝑜𝑠𝜃
circuit to compare the measured value to
calculated value of a given circuit.
6. Compute and record the magnitude and
phase angle of the impedance using the
MATERIALS
equation Z= R + RL + jXL – JXC. Use
Multisim
3uF for the value of C, 1.006H for the
Is a simulation tool that can be
used to speed up the analysis and
design of circuits containing
digital
devices,
transistors,
diodes, op amps, and even
value of L and for the resistance is
computed based on the specification of
the lamp.
7. Compute and record for the total power
using the formula.
𝑃𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 = 𝑆𝑐𝑜𝑠𝜃
motors.
8. Compute and record the reactive power and
METHOD
apparent power using the formula. Use the
1. Open NI Multisim 14.2, which allows users
to build, design, learn, and share circuits and
computed values and record it as
computed.
electronics online, and draw the circuit in
Figure 1 on the canvas.
2. Measure the total current. Record the current
𝑄𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 = √𝑆 2 − 𝑃2
reading. Refer to figure 2.
3. Measure the voltage e T. Record the data.
9. Compute
for
(measure)
Refer to figure 3.
4. Using Ohm’s Law, compute the voltage and
the
and
reactive
apparent
power
power
(measured) using the formula.
current for each component. Record it as a
𝑄 = 𝑃𝑡𝑎𝑛𝜃
measured value. Use the formula
𝑆 = 𝑃/𝑐𝑜𝑠 𝑐𝑜𝑠 𝜃
𝑉𝑡
𝑍=
𝐼𝑡
𝑍=
𝑉2
𝑍
𝑆𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 =
10.
220
0.3145
Compute
the
percent
difference
between the measure and the computed
value of the impedance.
𝑍 = 687.5 𝛺
5. Measure the power factor and power of the
system depending on your set up and record
your data:
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
Workbench
Computation
%
Difference
ZT
687.5 𝛺
699.4436 Ω
1.74%
P
49. 527 W
47.8834 W
3.32%
Q
50.5277
VAr
49.9552 VAr
1.13%
S
70.752 VA
69.1979 VA
2.20 %
p.f
(cos)
0.7
0.69
1.43%
Figure 2. Getting the total current of the
AC supply
Table 1: Simulation and Computation
Result of Power
This table 1 shows the simulation and
computation results for obtaining power
values in the RLC circuit. The columns are
Workbench,
Computations and
Percent
Figure 3. Getting the total voltage of the
Difference results. Respectively to the rows
AC supply
are Impedance, Real power, Reactive power,
Apparent power, and p.f (cos).
CIRCUIT DIAGRAM
Figure 4. Getting the power factor and
power of the system
Figure 1. Circuit Diagram
Manual Computation
For the resistance of the lamp (R)
RESULTS AND DISCUSSION
R=
This section analyses the results of the
experiment including their figures during the
𝑉2
𝑃
So,
V= 220 V; P= 100W
experiment.
R=
(220 𝑉)2
(100 𝑊)
R = 484 Ω
𝑝𝑓 = 𝑐𝑜𝑠𝜃
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
𝑅
𝑍
699.4436 Ω < 46. 2131°
484 𝛺
699.4436 𝛺
For the total current
𝑝𝑓 =
𝑝𝑓 =
𝑍𝑇 =
𝑝𝑓 = 0.69
𝐼𝑇 =
For the reactance of the inductor (𝑋𝐿 )
𝑉𝑇
𝐼𝑇
𝑉𝑇
𝑍𝑇
So,
𝑋𝐿 = 2𝜋𝑓𝐿
𝑉𝑇 = 220 V; 𝑍𝑇 = 699.4436 Ω
So,
𝐼𝑇 =
f = 60 Hz; L=1.006 H
(220 𝑉)
(699.4436 𝛺)
𝑋𝐿 = 2𝜋(60 𝐻𝑧)(1.006𝐻)
𝐼𝑇 = 0.3145357253 A
𝑋𝐿 = 379. 2530651 Ω
𝐼𝑇 = 0.3145 A
𝑋𝐿 = 379. 2531 Ω
Since the circuit is in series,
𝐼𝑇 = 𝑖𝑅 = 𝑖𝐿 =𝑖𝐶
For the resistance of the capacitor (𝑋𝐶 )
𝑋𝐶 =
For the lamp voltage (𝑒𝑅 )
106
2𝜋𝑓𝐶
R=
𝑒𝑅 = 𝑖𝑅 𝑅
So,
So,
f = 60 Hz; C = 3µF
𝑋𝐶 =
106
𝑖𝑅 = 0.3145357253 A; R = 484Ω
2𝜋(60 𝐻𝑧)(3µ𝐹)
𝑒𝑅 = (0.3145357253 𝐴) (484Ω)
𝑋𝐶 = 884.1941283 Ω
𝑒𝑅 = 152.235291 V
𝑋𝐶 = 884.1941 Ω
𝑒𝑅 = 152.2353 V
For the total impedance (𝑍𝑇 )
For the inductor’s voltage (𝑒𝐿 )
𝑍𝑇 = √𝑅 2 + (𝑋𝐿 − 𝑋𝐶 )2
𝑋𝐿 =
So,
R = 484Ω; 𝑋𝐿 = 379. 2531 Ω; 𝑋𝐶 = 884.1941 Ω
𝑍𝑇 =
𝑒𝑅
𝑖𝑅
√(484𝛺)2
= (379. 2531 𝛺 − 884.1941
𝑒𝐿
𝑖𝐿
𝑒𝐿 = 𝑖𝐿 𝑋𝐿
So,
𝛺)2
𝑖𝐿 = 0.3145357253 A; 𝑋𝐿 = 379. 2531 Ω
𝑍𝑇 = 699.4436457 Ω
𝑒𝐿 = (0.3145357253 A)(379. 2531 Ω)
𝑍𝑇 = 699.4436 Ω
𝑒𝐿 = 119. 2886489 V
𝑒𝐿 = 119. 2886 V
For the phase angle (𝜃)
𝜃 = 𝑡𝑎𝑛−1
(𝑋𝐿 − 𝑋𝐶)
𝑅
For the capacitor’s voltage (𝑒𝐶 )
So,
𝑋𝐶 =
R = 484Ω; 𝑋𝐿 = 379. 2531 Ω; 𝑋𝐶 = 884.1941 Ω
𝜃=
(379.2531 𝛺 − 884.1941 𝛺)
𝑡𝑎𝑛−1
484𝛺
𝜃 = 𝑡𝑎𝑛−1
𝑒𝐶
𝑖𝐶
𝑒𝐶 = 𝑖𝐶 𝑋𝐶
So,
(− 504.941𝛺)
𝑖𝐿 = 0.3145357253 A; 𝑋𝐶 = 884.1941 Ω
484𝛺
𝜃 = -46. 2131°
𝑒𝐶 = (0.3145357253 A) (884.1941 Ω)
𝜃 = 46. 2131°
𝑒𝐶 = 278.1106325 V
𝑒𝐶 = 278.1106 V
Therefore, the value of 𝑍𝑇 is:
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
For the apparent power (Scomputed)
Scomputed =
𝑉2
𝑍
𝑆 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒
=
So,
𝑉𝑇 = 220 V; 𝑍𝑇 = 699.4436 Ω
Scomputed =
/69.1979 𝑉𝐴 − 70.752 𝑉𝐴/
70.752 𝑉𝐴
(100)
𝑆 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 = 2.20%
(220 𝑉)2
(699.4436 𝛺)
Scomputed = 69.19785956 VA
𝑝. 𝑓 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 =
Scomputed = 69.1979 VA
/0.69 − 0.7/
0.7
(100)
𝑝. 𝑓 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 = 1.43%
For the real power (Pcomputed)
Questions:
Pcomputed = Scos𝜃
1. Do the workbench and computational
So,
values of real, apparent and reactive
S = 69.19785956 VA; 𝜃 = -46. 2131°
power agree?
Pcomputed = (69.19785956 VA) cos (-46.
Answer: Yes, the workbench and
2131°)
computational values of real, apparent,
Pcomputed = 47.8834 W
and reactive power agree with only a
little percentage variation, and the
For the reactive power (Qcomputed)
workbench and computational values
𝑄𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 = √𝑆 2 − 𝑃2
produce correct findings.
2. Give
So,
possible
reasons
for
any
discrepancies. Any other observations or
S = 69.19785956 VA; P = 47.8834 VA
comments?
𝑄𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 = √69.19785956 2 − 47.8834 2
Answer: In this laboratory exercise, the
𝑄𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 = 49.9552 VAr
discrepancy between benchwork and
pf = 0.7
manual computation demonstrates a lack
of balance between two things that
PERCENT DIFFERENCE
should be similar, as illustrated by the
percent error solution. Rounding off the
final answer and neglecting to complete
𝑧𝑇 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒
=
the
/699.4436 − 687.5/
(100)
687.5
of
the
anomalies.
CONCLUSION AND RECOMMENDATION
/47.8834 𝑊 − 49. 527 𝑊/
=
(100)
49. 527 𝑊
𝑃 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 = 3.32%
component
experiment could cause any errors or
𝑧𝑇 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 = 1.74%
𝑃 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒
hardwired
From this laboratory activity, we can
conclude that “active power" is power that
actually performs work. Reactive power is
𝑄 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒
=
/49.9552 𝑉𝐴𝑟 − 50.5277 𝑉𝐴𝑟/
(100)
50.5277 𝑉𝐴𝑟
𝑄 % 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 = 1.13%
defined as power in which the current is out of
phase with the voltage, and this will help us to
know that we can calculate the real power and the
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EE 419 Basic Electrical Engineering | Laboratory Experiment No 4. | December 02, 2021
power factor through a wattmeter. For example,
THOUGHTS:
current that charges a resistor or current that
Garcia, Danarie D.
forms a magnetic field around a circuit. To obtain
This laboratory experiment is interesting
and engaging since it uses NI Circuit Multisim for
hands-on simulation to demonstrate and explain
the real, reactive and apparent power
mesurements. It deepened our comprehension
while also testing our mathematical abilities by
showing that the multisim findings are same
when manually calculated.
the true power and power factor, plug the
wattmeter in series with the IT branch and in
parallel with the power supply. After modifying
the above formula here on laboratory activity, we
can obtain the values of apparent power and
reactive power by using the power factor and
actual power. Furthermore, we can acquire the
simulated value of the impedance using the
voltage level and total current measured in the
circuit diagram, and we'll get the phase angle and
the amount of the resistor for the calculated value
through using RL, XC, and XL.
Utilizing different functions of Multisim
has been a great help for the researchers for the
past
experiments
and
in
this
particular
experiment. Applying the learnings about Ohm's
Law and utilizing it in the experiment helped the
researchers to estimate voltage and current.
Analyzing laws and principles from the past
activities can be an advantage also in estimating
the impedance of the given circuit in this
experiment. Overall, applying different learnings
from the previous activities with the help of
teamwork and unity will help the team to achieve
what needs to be achieved.
REFERENCES
[1] All About Circuit (n.d.). True, Reactive, and
Apparent
Power.
Retrieved
from
https://www.allaboutcircuits.com/textbook/
alternating-current/chpt-11/true-reactiveand-apparent-power/
[2] Menu, JJ. (February 8, 2016). Real Power vs
Apparent Power vs Reactive Power: What is
the
difference?
Retrieved
from
https://www.arrow.com/en/research-andevents/articles/real-vs-reactive-power
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