IRJET- Automated Energy Monitering System and Power Factor Improvement

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 02 | Feb 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 2572
AUTOMATED ENERGY MONITERING SYSTEM AND POWER FACTOR
IMPROVEMENT
Mr. Manish B. Zode
1
, Mr. Aditya B. Dhanke
2
, Ms. Shital V. Uike
3
, Prof. N. V. Yawale
4
1,2,3
UG Students, Electrical Engineering, DES’sCOET, Dhamangaon Rly, Maharashtra (India)
4
Assitant Professor, Electrical Engineering, DES’sCOET, Dhamangaon Rly, Maharashtra (India)
---------------------------------------------------------------------***----------------------------------------------------------------------
Abstract - Generation of power at present is decisive as
wastage of power is a global concern. Power factor measures
and power efficiency is an important aspect in improving the
quality of supply. In most power systems, a low power factor
resulting from an increasing use of inductive loads is often
overlooked. A power factor correction unit would permit the
system to improve its power factor close to unity for
economical operation. The advantages of correction of power
factor include reduced power system losses, increased load
carrying capabilities, improved voltages and much more. The
aim of this seminar is to build an Automatic Power Factor
Correction Unit, which is able to monitor the energy
consumption of a system and automatically improve itspower
factor. An open source energy monitoring study was
implemented in the design for accuratepowercalculation. The
APFC device measure the reactive power consumed by a
system’s inductive load and compensates the lagging power
factor using capacitance from a capacitor bank.
Key words:
Alternating current, Current Transformer, Potential
Transformer, Power Factor, Power Factor Correction.
1. INTRODUCTION
Power factor is defined as the ratiobetweentheactual
load power and the apparent load power drawn by an
electrical load. It is simply a measure of how efficient the
load current is being converted into useful work output. the
power factor of a system less economically operates. A low
power factor can be the result of a significant phase
difference between voltageandcurrentloadterminalsa high
harmonic content or even a distorted current waveform.
Generally it is the value of inductive loads such as induction
motor power transformers or inductionfurnacesthatcauses
a current to lag behind voltage. A low power factor resulting
from inductive loads can be improved by power factor
correction method but a poor power factor resulting from
distorted current waveform requires a change in equipment
design or addition of harmonic filters. Since power factor in
inductive loads is generalised. they have to be given with
reactive power in order to reduce increased power
consumption of the machine.
All inductive loads require active power to performthe
actual work and reactive power to maintain the magnetic
field. This reactive power is necessary for the equipment to
operate, but imposes an undesirable burden on the supply
causing the current to be out of phase with the voltage. Low
power factor can also result when inactive motors work at
less than full load such as a surface grinder performing a
light cut a circular saw that is only resolve, an air
compressor that is unloaded etc. Losses generate by low
power factor are due to the reactive current flowing in the
system and can be eliminated using PFC.
Power factor correction is the process of compensating
a lagging current by a leading current through connecting
capacitance to the supply. Capacitors contained in most
power factor correction system carry current that leads
voltage and produces a leading power factor. A sufficient
capacitance is connected so that power factor is adjust as
close to unity as possible. Theoretically capacitors could
provide 100% of the needed reactive power however
practically correcting power factor much nearer to unit may
result in harmonic distortion.Ifcapacitorsareconnectedtoa
circuit that operates nominally at a lagging power factor the
extent to which the circuit lags will reduce proportionately.
Power factor correction is applied to neutralize as much of
the magnetizing current as possible and to reduce losses in
the distribution system. It action many benefits to the
economic electrical consumer including reduced utility bills
by eliminating charges on reactive power, reduced losses
making extra KVA available from the existing supply. thus it
improves energy efficiencythissystemisbasedontechnique
of continuous monitoring of the systems parameterssuchas
voltage and current with the use of potential transformer
and current transformer respectively. Through continuous
monitoring phase difference betweenthetwo quantities will
be calculated continuously and depending upon phase
difference correspondingly suitable amount of capacitors
will be switched on or off in the system in line to improve
power factor as close as unity. As there is no moving part in
capacitors hence switching losses arelessascomparetothat
of static compensation also no extra motor is required for
power factor correction and hence amount is much less as
compare to that of power factor correction.
2. Existing System
There are several existing procedures for power factor
correction in modern days.
A. Synchronous Condenser
It is synchronous motor that rotates under no load
condition. Asynchronous motor shows capacitive behavior

while operating in over-excited mode. By controlling the
field excitation power factor can be adjustedcontinuously.It
provides step-less PF correction and not affected by system
harmonics. But its installation and maintenance is costly
B. Static Capacitor Bank
Capacitor causes leading power factor as it shifts
current ahead of the voltage. So to correct lagging power
factor, it is a convenient method for which this method is
practiced worldwide vastly. Though it has some limitations
like the inability to absorb harmonics and doesn’t provide
step-less correction, it is a popular choice for PFC for its low
cost of installation and maintenance
3. Working of Proposed System
3.1: Power Supply: The AC mains can supply an AC power
of 230V at 50Hz frequency. But itrequiresDCpowerinorder
to operate the modules. A voltage transformerisusedtostep
down the 230V supply to 12V. This AC signal is then
converted to DC through a bridge rectifier followed by clean
capacitors. The final stable DC outputs are achieved using
voltage regulator IC.
3.2: Voltage Sensor Circuit: The mains 230V AC is stepped
down to 12V AC. A voltage divider circuit divides this 12V in
1:10 ratio which provides around 1.2V sinusoid signal. A DC
offset of 2.5V is applied to the sinusoidal signal. As a result
the whole sinusoid can be observed in thepositive boundary
and the microcontroller can read the whole sinusoid signal
through its analog input.
3.3: Current Sensor Circuit: The current signal flowing
through the mains is retrieved through a current
transformer. A burden resistortransformsthecurrentsignal
into a voltage form that perform the properties of the
current sinusoid. ADC offset voltage of 2.5V is applied to the
sinusoidal signal so that the reference point is lifted up and
the whole sinusoid can be read in analog mode within its
operating range.
3.4: Inductive Load Network: The inductive load network
is a combination of loads having inductive characteristics
and consuming huge electrical power due to lagging power
factor. The network collectively simulates a highly inductive
load controlling at a very low power factor.
3.5: Relay Drivers: The loads and capacitors are connected
to a high voltage circuit. In order to appropriate these high
voltage components with microcontroller relay is used for
convert operation on capacitors in high voltage circuit
through the control signal from microcontroller keeping the
microcontroller safe and electrically isolated from high
voltage.
3.6: Display: The calculated power parameters current
power factor mains voltage mains current real andapparent
power are continuously displayed on a 20x4 Liquid Crystal
Display monitor
3.7: Capacitor Bank: Capacitor bank is the collection of
capacitors of different values. Series and parallel
combination of different capacitor provide a range of
capacitance required to compensate poor power factor. The
sizing of capacitors is determined based on the required
KVAR expect by the load network.
Fig.1: Block Diagram of the APFC and Energy Monitoring
System
4. Circuit Components
4.1: Power Factor Correction
Automatic Power Factor detection and correction
operates on the principal ofconstantlymonitoringthepower
factor of the system and to initiate the requiredcorrection in
case the power factor is less than the set value of power
factor The current and voltage signals are sampled by
employing instrument transformersconnectedinthecircuit.
The instrument transformers give stepped down values of
current and voltage, whose magnitude is directly
proportional to the circuit current and voltage. The sampled
analog signals are converted to suitable digital signalsbythe
zero crossing detectors, which changes state at each zero
crossing of the current and voltage signals. The ZCD signals
are then added in order to obtain pulseswhichrepresentthe
time difference between the zero crossing of thecurrentand
voltage signals. The time period of these signals is measured
by the internal timer circuit of the Arduino by using the
function pulse in which gives the time period in micro
seconds. The time period obtained is used to calculate the
power factor of the circuit.
4.2: Voltage Sensing
The transformer used for thisprojectisa step-down
transformer. The potential transformer is fed with
alternating voltage with a value of 220V and thevalueisstep

down to less than 5V. The output of the transformer is
connected to diode. The diode act as rectifier which
converted the voltage wave into pulsating D.C. wave to be
detected by the microcontroller. The output of the diode is
then connected to the zero-crossing detector where zero
crossing detection is used to sense sine wave zero crossing
from positive half cycle to negative half cycle or vice-versa
4.3: Current Sensing
The current sensing circuit works the same as
voltage sensing circuit but this circuit detects current. The
input signal is connected to the step down current
transformer where it converts high current intolowcurrent
output for the use of different electrical circuits. The reason
current transformer is used because, Op-amp requires
current less than 50mA. Output of current transformer is
connected to diode. Diode function as a rectifierinthecircuit
and it is connected to zero-crossing detector. This zero-
crossing detector detects sine wave zero crossing
5. CONCLUSIONS
It is concluded that automatic power factor
correction techniques can be applied in industries,
commercial lines and power distribution system to increase
stability and efficiency of the system. The APFC device helps
to pull in high current drawn from the system and reduce
charges on utility bills. A reduced power consumption
results in lower greenhouse gas emissions and fossil fuel
depletion by power stations and would benefit the
environment.
6. ACKNOWLEDGEMENT
We take this opportunity to express ourgratitude
and indebtedness to our guide prof. N. Yawale Assistant
Professor, Electrical (E & P) department, who is a
constant source of guidance and inspirationin preparing
this work.
We express our sincere gratitude towards H.o.D.,
Prof. P. V. Raut, and Assistant Professor whose constant
help and encouragement helped us to complete our
Project report. We are grateful to Dr. L. P. Dhamande,
Principal for his encouragement and support.
We are also thankful to all the staff members of
Electrical (E & P) department, whose suggestions helped
us to complete the Project Work.
REFERENCES
[1]Anant Kumar Tiwari, Durga Sharma, Vijay Kumar
Sharma (2014) “Automatic power factor correction
using capacitive bank.” Int Journal of Research and
Applications, Volume-4, 2014, pp.393-395.
[2] Barsoum, Nader (2007) “Programming ofPICMicro-
Controller for Power Factor Correction” IEEE
Conference on Modeling & Simulation, Pages:19-25.
[3]Dr. Kurt Schipman and Dr. Francois Delince, “The
importance of good power quality”, ABB power
quality Belgium.
[4] Jones, L. D.; Blackwell, D. (1983) “Energy Saver
Power Factor Controller for Synchronous Motors”, IEEE
Transactions on PowerApparatusandSystems,Volume:
5, Issue: 5, Pages: 1391-1394.
[5] Jos Arrillaga, Neville R. Watson (2003). “Power
System Harmonics” 2nd.ed. Chichester: John Wiley
[6]Keith Harker (1998). “Power System Commissioning
and Maintenance practice.” London: Institution of
Electrical Engineers.
[7] Md. Shohel Rana, Md. Naim Miah &HabiburRahman,
“Automatic Power Factor Improvement by using
Microcontroller” Volume 13 Issue 6 Version 1.0 Year
2013 from University of Engineering & Technology
Rajshahi- 6204, Bangladesh.
[8]Mr. Satyasuranjeet Behera, Mr. Sibasis Mohapatra,
Mr. Monalisa Bisoi “Automatic Power Factor Correction
by Microcontroller 8051”. Department of Electrical
Engineering, National InstituteofTechnology,Rourkela.
[9] Rakendu Mandal; Sanjoy Kumar Basu; Asim Kar;
Shyama Pada Chowdhury (1994) “A Microcomputer –
Based Power Factor Controller”, IEEE Transactions on
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[10] Reetam Sen Biswas, Dr. Satadal Mal, Automatic
Power Factor improvement using Microcontroller,
Electrical Enginering, Heritage Institute of Technology,
Kolkata.

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