2015 First Workshop on Smart Grid and Renewable Energy (SGRE 2015)
Power Quality Effect of Using Incandescent, Fluorescent, CFL and LED Lamps on Utility Grid Mohd. Shafiul Islam, Noor Alam Chowdhury, Abdul Kader Sakil, Amith Khandakar, AtifIqbal, Haitham Abu-Rub*
Electrical Engineering Dept., College of Engineering, Qatar University, Doha, Qatar *Dept. of Electrical & Computer Engineering, Texas A&M University at Qatar, Doha, Qatar
[email protected],
[email protected],
[email protected],
[email protected],
[email protected], haitham.abu
[email protected]
Abstract-
One of the major electrical load on a utility grid is
industrial, street and residential lightings. To enhance the energy efficiency and as a measure of energy conservation, incandescent lamps (IL) are replaced with the modern lights.
Replacing
incandescent lamps with compact fluorescent lamp (CFL) and fluorescent lamp (FL) is one of the measures taken by the authorities to reduce the energy consumption and enhance energy efficiency. Both the CFLs and LEDs are the sources of harmonics as electronic circuits are used in for their ignition. These harmonic sources adversely affect other loads connected to the same bus. It also affects the grid in terms of high reactive power demand (due to poor power factor), distortion in currents and hence overall degrading the power quality. Power quality measurements such as power factor, voltage and current total harmonic distortion (THD) are done and reported in this paper. Different scenarios are considered with full and partial replacement of incandescent
lamps. A comprehensive comparison between incandescent, CFL and LED are made in terms of these power quality measurements.
From the result analysis, it is noted that, the CFL consumes less active power than incandescent. But, the THD is considerably higher in CFL than incandescent. While comparing LED and CFL, the power factor of LED is found poor compared to CFL. The simulation and experimental approaches are used in this work.
Keywords-power quality; harmonics; compact fluorescent lamp; total harmonic distortion, LEDs, Utility grid I.
used to verifY the results obtained from Janitza. The results are then fed to EasyPower Power analyzing software to measure the harmonic distortion in the point of common coupling (PCC). For large scale effect at PCC, scaling factor has been changed. The values are then compared with IEEE Std. 519, voltage and current harmonic distortion limits. The solutions to reduce the harmonic distortion is also discussed. II. HARMONIC DISTORTION AND POWER FACTOR
A. Harmonic Distortion The definition of harmonics is based on the application of the Fourier transform and superposition to the voltage and current waveforms. An ideal power system contains only the fundamental harmonic - 50Hz (Indian sub-continent, Gulf region, and Europe etc) or 60Hz (USA and Canada). Harmonics are mainly generated from non-linear loads such as, transformers, electric motors, generators, arc furnaces, arc welders, DC converters, inverters, Television power supplies, switched mode power supplies, high pressure discharge lamps, compact fluorescent lamps, light emitting diodes, laptop and mobile phone chargers and other similar electronics and power electronics equipment [2][3]. The current i(t) can be expanded into a Fourier series as follows,
i(t)
INTRODUCTION
Electric lighting system consumes significant amount of electricity around the world. Different types of lighting systems are used in residential and commercial complexes, industries, offices, sports facilities, highways and streets [1]. General lighting system usually incandescent lamps are being replaced with solid state lighting systems due to energy efficiency reasons. Solid state lighting systems such as compact fluorescent lamps (CFLs), fluorescent lamps, metal halide lamps, LEDs etc, uses electronics to operate the lamps. Electronic switching system have negative impact due to poor power factor and injecting higher harmonics in the source side current [2]. These harmonic sources also affects other loads connected to the same bus. The methodology of the project is to measure the total harmonic distortion (THD) as well as the individual harmonics of incandescent, fluorescent, CFL and LED, using Janitza UMG5l2 power analyzer. Fluke 43B power analyzer is also
=an sin cot + bu cos cot
(1)
Where,
an � tn: iCt) sin(nwt) dCwt) bn =.; f0211: iCt) cos(nwt) d(wt) =
IT
0
(2) (3 )
The root mean square of the current is expressed by,
IRMs
=
.J Q'1� + h�
(4)
The harmonic distortion root mean square of current can be calculated as,
IH-RMS
=.JIi + It +
. . .
. . . . .
+l�
The total harmonic distortion (THD) can be calculated as,
978-1-4673-6765-3/15/$31.00 ©2015
IEEE
(5)
2015 First Workshop on Smart Grid and Renewable Energy (SGRE 2015)
(6)
three (L3) are connected and tested for One hour with the Janitza Power Analyzer. The resulting harmonic spectrum of current drawn by three typed of lamps are shown in Fig. Ol.
Similarly the voltage x(t) can be expanded into a fourier series as follows.
vet) =an sin rot + bn cos rot
(7)
Where,
� fo'.1£ iCt) s inCnwt) d Cwt) bn = � g1£ iCt) cosCnwt) d(wt)
(8)
an =
(9) Figure 01: Current THO of CFL, LED and incandescent using Janitza.
Root mean square of voltage can be expressed by, VR MS
=
(10)
.J� + b�
Harmonic distortion root mean square of voltage can be described as,
VH.RJ.,fS =.JIi RMS
+
... ... . .
+I�
RMS
(11)
Total harmonic distortion of voltage can be calculated as, % THDv = B.
Jl�
From the Current Harmonics its easily noticed that CFL have more distortion than LED lamps but less than the incandescent lamp. The 3rd Harmonic of CFL is 73.9 rnA which is almost near to 1st Harmonics (fundamental). On the other hand the 3rd Harmonics of LED is 33 rnA which almost four time less than that of 1st Harmonics (fundamental) i.e. the 3rd harmonic is about 25% of the fundamental. In case oflncandescent lamp the 3rd Harmonics is almost 0 rnA The current drawn by incandescent lamp is harmonic free. It acts as a resistive load to the utility grid. LED consumes less active power and also have less harmonic distortion than CFL, but the power factor of CFL is better than LED. The power factor for LED lamps are 0.14 where as for CFL it is 0.54 and for incandescent 1.00 as it is a resistive load. Hence CFL require large reactive power. The total harmonic distortion for CFL, LED and incandescent is 74.2%, 23.7% and l.7%, respectively. .
RMS+
..
·
� RMS
.... ·+I
l1RMS
.,
100
(1 2)
Power Factor
Modem lighting system also affects the power factor. The power factor of compact fluorescent lamp and light emitting diode is very less, which influences the overall power factor of the bus. The ratio of real power to the apparent power is the power factor. On the other hand the power that is consumed and converted by the system is real power [4]. III. P OWER QUALITY MEASUREMENT Several ways are there to compare between different types of lamps but usually it's done either on the basis of their lumen output or on the basis of electrical watt. This experiment was done on the basis of their lumen output (one CFL of 20 watt or two LEOs of 5 watt is equivalent to 100 watt Incandescent). Current, real power, harmonics and power factors of Compact fluorescent lamp (CFL), Light emitting diode (LED) and Incandescent are observed and measures using two types of Equipment : a) Janitza Power Analyzer b) Fluke Power analyzer. The experiment is done using following steps: 1.
Separate Measurement
2.
Mixed Measurement
A. Experiment Using Janitza Power Quality Analyzer Janitza power analyzer UMG 512 have three-phase input facilities that is used to perform the experiment. The three types of lamps CFL, LED and Incandescent lamps connected to the device using three input lines namely L1, L2 and L3 respectively. Keeping the output lumen same the number of CFL and LED lamps were selected. One Compact fluorescent lamp (CFL) of 20 W in Line one (Ll), Two Light emitting diode (LED) of 5W in line two (L2) and one Incandescent lamp of 100 W in line
In a room if all the lamps are CFL, then the harmonic distortion in the current drawn is higher compared to LED. On the other hand if all the lamps are LED the power factor are too less. Moreover, if all the lamps are Incandescent the real power or energy requirement will be more, as the lumen output of a 1OOW bulb is same as 20W CFL or lO W LED. To overcome all these problems it was decided to have multiple types lamps or using mix of lamps. So the following the experiment was done for 1000W: 50 % Incandescent + 50 % CFL 50 % Incandescent + 50 % LED 50 % LED + 50 % CFL 40 % Incandescent + 30 % CFL + 30% LED First case is used for 50 % Incandescent lamp and 50 % CFL. The power factor of this combination of lamps is increased to 0.97, whereas the power factor for CFL alone was 0.54. The total harmonic distortion of this combination of lamps are also reduced to 18.61%. In second case, 50 % Incandescent lamp and 50 % LED were connected. In this step it is noticed that the real power and power factor are less than previous case. In this case, the total harmonic distortion is 8.47% and the power factor is 0.94. In third case, half of CFL and half of LED lamps are connected. The power factor of this combination is 0.49 and the THO is 42.57%. The total harmonic distortion of third case is higher than the second case, but it consumes less real power than
201S First Workshop on Smart Grid and Renewable Energy (SGRE 201S) the other two cases. In last case, a combination of 40% incandescent, 30% CFL and 30% LED lamps are connected. The THD of this combination is 13.74% and power factor is 0.9S. Table 1 shows the comparison between all the investigated cases. From the comparison table, it is clear that, if an electronic load is used with resistive load, the THD as well as power factor improves. If LED and CFL is connected the THD is maximum but the consumed real power is less. If incandescent and CFL is connected the THD reduces but the consumed real power increases. Similar result is seen for LED and incandescent combination. TABLE 01
COMPARISON OF CFL, LED AND INCANDESCENT LAMPS Power
Power
(KW)
50% IND +50%CFL 50% IND +50% LED 50% LED +50%CFL
Factor
%THD
1.11
0.97
18.61
0.56
0.94
8.47
0.15
0.49
42.57
0.40
0.95
13.74
Same experiment is conducted using Fluke 43B Power analyzer to verify the results. Figure 03 shows the current THD for incandescent, CFL and LED lamps. .. _t.'!t;all.ll.ll. '''' 1S9S" 4.20, 100", o·
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