Advanced Power Quality: Experiments in Harmonics using NEPLAN
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This document discusses the effects of harmonics on power quality and explores solutions using NEPLAN. It includes a case study on different types of lamps and their power factors, total harmonic distortion (THD), and luminous flux.
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Advanced Power Quality (Experiments in harmonics using “NEPLAN”)
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Table of Contents 1.Abstract 2.Introduction 3.Literature Review/Theoretical background 4.Case study 5.Methodologies/Experiment description(Circuit) 6.Results(Simulation) 7.Analysis 8.Conclusions 9.Further work 10.References
Abstract: A good percentage of total electricity consumption is used for the lighting load. For the developing countries the percentage is 20-50% whereas on the world level, it is 19% [1,2]. In order to light the indoor and outdoor places, a large amount of electricity is needed. With the growing population, this need for power is also growing day by day. Hence, new type of energy saving lamps (ESLs) are coming into the market, in order to replace the incandescent lamps. Introduction: The ESLs need lesser amount of active power as compared to incandescent lamps (if luminous flux remains the same). ESL has low power consumption and longer lifetime[3]. Some examples of ESLs are compact fluorescent lamp(CFL), light emitting diode(LED) etc. They make use of electronic ballast. Due to it, their power factor (PF) is low. It means reactivepowerbecomeslow.Wemustchooseadevicewhichreducesthepower consumption and makes the power system stable. We study a CFL, an LED, a fluorescent lamp and an incandescent lamp. Literature Review/Theoretical background: Harmonic study is really important. We will understand the power system harmonics, their causes, their effects, the standards or guidelines available to help control harmonics and the ways to mitigate harmonics. Harmonics are problem causing agents. They are caused by non-linear loads. Nowadays, the non-ideal load types are increasing tremendously. Harmonic distortion depicts thedegree to which awaveform deviates from its pure sinusoidal values as a result of summation of all the harmonic elements. An ideal sine wave has zero harmonic components. If the fundamental frequency of a waveform is 50Hz, the 2nd, 3rd, 4thand 5thharmonic components will be at 100Hz, 150Hz, 200Hz, 250Hz, respectively. We measure the active power as well as the harmonics developed through an experiment. A consumer pays for the active power only. Active power(P) = VI cos φ V= Voltage applied across the load
I = Current flowing through the load Cos φ = PF The use of ESLs leads to generation of harmonics which may cause power loss and make the power system unstable. Power Factor = cos φ Φ = Angle of displacement = phase angle between 1stharmonic voltage wave and current wave PF = P/S = Active Power/Apparent Power = cos φ ESLshelpingeneratinglowPF.Hence,thereactivepowerincreases.Some disadvantages are unwanted cable heating due to which cable size increases, line loss increases,voltageregulationdecreasesandefficiencyofthepowersystemalso decreases. The presence of harmonics in electrical systems can be understood as a distortion and deviation in the current and voltage waveforms from ideal sinusoidal waveforms. They are represented in the form of a wave that has a frequency that is an integral multiple of the fundamental frequency. Harmonic current and voltage arises due to the presence of non- linear loads that are connected to a power system. Harmonics are harmful and unwanted. Harmonics overlay themselves on the fundamental waveform which is purely sinusoidal, cause distortion in it and change its magnitude. A high distortion in current can give rise to various problems like an increase in eddy current loss in the transformer and generator. The I2R losses increase in conductors and generator windings. There is a problem of neutral overloading. All these factors cause a decrease in the efficiency of the power system. A high value of voltage distortion is also not desirable. I can cause various problems like failure of switched mode power supply (SMPS) in PLCs, computers or other instruments. It can lead to malfunction of Auto Voltage Regulator (AVR) in generator. It can give false reading on critical sensors and instruments. It can lead to an increase of the operating temperature of induction motor windings and rotor bars which can also cause premature failure of motor. So, we see that harmonics are really harmful.
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A non-linear load is a load that draws current in a non-sinusoidal manner despite of the voltage being a perfect sine wave. Some examples of non-linear loads are Static Power Converters, Pulse Width Modulated (PWM) Drives, Switch Mode Power Supply, Inverter, Arc Furnaces, Variable Speed Drives(VFD), fluorescent lights etc. ESL leads to the generation of harmonics. If the frequency of main frequency wave is ‘f’, then the harmonics are components with frequencies 2f, 3f, 4f,.... and so on. The rms voltage and current in ESL contain all these components. The even harmonics are negligible. Total Harmonic Distortion (THD) denotes total amount of harmonics present in the main RMS voltage. Vr2= V2+ Vh2 Ir2= I2+ Ih2 V= first harmonic component of V wave Vh = Distorted component of V wave I = first harmonic component of I wave Ih = Distorted component of I wave Luminus flux is the power of the visible light which is emitted by a light source. It is measured in lumen. The device used to measure it is called Multi-Photometer. There are various solutions available for reducing the effects of harmonics. Every method has its own place. Every method makes the system complex also. The addition of extra equipment needs extra costs. The heat losses increase due to which additional equipment is needed for cooling the system. A larger footprint also needs a larger space. The complexity of installation and the costs involved also increase due to additional power cabling and use of current transformers. The generator interactions become difficult. The performance of the application also is affected. A large value of impedance affects load performance. The solution also depends on many factors like short circuit capacity of the source, rectifier devices used, design of converter, the built in inductance or capacitance of internal and external filters and the inductance added at the rectifier or the DC bus. The harmonic
solutionsappliedpernonlineardevicearereducedharmonicdesignswithlow capacitance, passive filters by adding inductive impedances (like line reactance, DC bus chokesorisolationtransformers),5thharmonicfilters,multi-pulsetransformersor converters and active front end converters (AFE converter). Every solution type which is used has some specifications which are mentioned here. The C-lesstechnologyisusedonlyforpumpandfanapplications.TheTotalharmonic distortion is about 35-40%. It helps in reducing high order harmonics. The 5thharmonic filters are dedicated to one load only. They are used when Total harmonic distortion is about 20%. It has moderate cost and heat and uses large space. With backup generators, we must be aware of the capacitance. The inductance used at input or DC bus applied is used when Total harmonic distortion is about 35-40%. Some added cost, space and heat is also there. The broadband filters are used in cases when total harmonic distortion levels are about 5- 8%. They are good for the fan and pump applications. They have moderate cost and heat butoccupyverylargespace.Butwemustbeawareofcapacitancewithbackup generators. In case of Muti-pulsing, for 12-p, Total harmonic distortion is 10% and for 18-p, its 5%. It has large cost and space but moderate amount of heat. It has no adverse application issues. A system solution comprises of Active harmonic filter (AHF). It is used in case of multiple and varied loads and applied in parallel to loads. It requires current transformers. It also does power factor correction and mains current balancing work. Case study: With the growing population, this need for power is also growing day by day. Hence, new type of energy saving lamps (ESLs) are coming into the market, in order to replace the incandescent lamps. We test all lamps individually for THD, % voltage harmonics and % current harmonics. It has been done upto 50thorder. Also, the power factor(PF) and the luminous flux (in lumen) has been measured. We have used a total of 11 lamps for the experiment. They are of different types. The first 4 are CFL lamps, next 4 are LED lamps, 1 is fluorescent lamp, 1 incandescent lamp and 1 intelligent LED lamp. The intelligent LED lamp is a kind of emergency light. We choose the lamps of different ratings.
We have to do power quality analysis. Voltage waveform is produced due to different loads present in the network. It causes a degradation in power quality. We evaluate the power quality within network under various conditions. We can use a software to automate the calculation of THD. The various components are attached. The line to line voltage is not a perfect sine wave. So, the power quality is affected by the components on the network. FFT can also be used for this analysis. THD is seen in % contribution of different orders. We can do the analysis at different points and conditions at different times. We do it for 50 harmonics. Somewhere the harmonics are low and somewhere high. By our study, we can analyse, where the harmonics are high and and find ways to reduce them. The total harmonic distortion (THD) is very high in case of intelligent LED light. It has high values for CFLs also. But it is lesser in case of LED. Fluorescent lamp and incandescent lamp have very low values of % total harmonic distortion (THD). Lumen value is very high in CFLs and incandescent lamp. It is low incase of LED and intelligent LED lamp. The lumen value is moderate for fluorescent lamp. Lumen/Watt is very high for LEDs. It has a low value in case of incandescent lamp and fluorescent lamp. It is moderate for CFLs and intelligent LED lamp. Methodologies/Experiment description(Circuit) We use an AC power supply unit that is based on SPWM (Sine-Wave Pulse Width Modulation) Technology. The presence of harmonics in electrical systems can be understood as a distortion and deviation in the current and voltage waveforms from ideal sinusoidal waveforms. They are represented in the form of a wave that has a frequency that is an integral multiple of the fundamental frequency. Harmonic current and voltage arises due to the presence of non- linear loads that are connected to a power system. Harmonics are harmful and unwanted. Harmonics overlay themselves on the fundamental waveform which is purely sinusoidal, cause distortion in it and change its magnitude. Experimental Block Diagram:
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AC Source 220VDigital Power MeterTested Light SourceDetectorMulti Photometer We obtain the data through various meters and use MS-Excel to analyse the data. We select the CFL and LED lamps with a rating below 26W. The rating of incandescent lamp is 60W. The rating of fluorescent lamp is 20W. We have to do power quality analysis. Voltage waveform is produced due to different loads present in the network. It causes a degradation in power quality. We evaluate the power quality within network under various conditions. We can use a software to automate the calculation of THD. The various components are attached. The line to line voltage is not a perfect sine wave. So, the power quality is affected by the components on the network. FFT can also be used for this analysis. THD is seen in % contribution of different orders. We can do the analysis at different points and conditions at different times. We do it for 50 harmonics. Somewhere the harmonics are low and somewhere high. By our study, we can analyse, where the harmonics are high and and find ways to reduce them. Fig. 1 Circuit Diagram
Fig. 2 Detailed Circuit Diagram The figure 1 and figure 2 show the circuit diagram of the NEPLAN circuit designed. Results(Simulation) The table 1 shown below shows the various parameters measured. We compare the power factor(PF), Input power, current, % THD, lumen and lumen/W for various lamps which are tested as follows: Table 1 Parameters LAMP RATIN GPF INPUT P(W)I(A)%THD LUME N LUMEN/ W CFL-A24 W0.5618 W0.15 A135 %132673.67 CFL-B23 W0.622 W0.17 A115 %135561.6 CFL-C26 W0.5719 W0.15 A124 %131269 CFL-D14W0.6314 W0.1 A88 %63045 LED-A12W0.9812 W0.06 A17 %110792 LED-B7W0.966.3 W0.03 A18 %722115 LED-C5W0.23 W0.06 A27 %19565 LED-D3W0.53.1 W0.03 A52 %28993
FLUORESCENT LAMP20W0.423 W0.3 A7 %68030 INCANDESCEN T LAMP60W164 W0.31 A2 %94614.8 INT EM LIGHT12W0.526 W0.05 A156 %46878 We find that the best power factor and %THD is shown by Incandescent lamp but its efficiency is not good. A good THD index is shown by Fluorescent lamp but it shows low power factor and efficiency. CFL technology shows current harmonic distortion and low power factor, but has a high efficiency. Analysis We see that incase of incandescent lamp, the power factor is unity and the power consumption is more as compared to the ESLs and lumen/W is very less. So, it has a very less value of efficiency. Incase of fluorescent lamp also, the efficiency is less as the lumen/W is less. If we consider the power factor, ESL is better than fluorescent lamp. But the % THD incase of ESL is large. If we consider the voltage and current harmonics, we find that even ordered harmonic are low for all lamps and odd ordered harmonics have some value. Voltage harmonics start diminishing after few harmonics and current harmonics are seen till higher orders also in ESL. LED has lower current harmonics than CFL technology. It has good efficiency. We have taken four CFLs with different ratings. CFL-A has a rating of 24 W, CFL-B of 23 W, CFL_C of 26 W and CFL-D of 14 W. 4 LEDs have been taken with ratings as LED-A of 12 W, LED-B of 7W, LED-C of 5W and LED-D of 3 W. The rating of fluorescent lapm is 20 W, of incandescent lamp is 60 W, and of intelligent LED lamp is 12 W. Next,wecomparevariousparametersorvalueswhicharemeasuredduringthe experiment. We find that incandescent lamp has a power factor of unity, i.e., cos φ = 1. Hence, φ = 0 degree. So, there is no phase shift between the voltage and current. LED shows higher power factor at higher ratings. CFLs show lower power factor values. The fluorescent lamp and intelligent LED light show moderate values of power factor. The total harmonic distortion (THD) is very high in case of intelligent LED light. It has high values for CFLs also. But it is lesser in case of LED. Fluorescent lamp and incandescent lamp have very low values of % total harmonic distortion (THD).
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Lumen value is very high in CFLs and incandescent lamp. It is low incase of LED and intelligent LED lamp. The lumen value is moderate for fluorescent lamp. Lumen/Watt is very high for LEDs. It has a low value in case of incandescent lamp and fluorescent lamp. It is moderate for CFLs and intelligent LED lamp. Conclusions We see that incase of incandescent lamp, the power factor is unity and the power consumption is more as compared to the ESLs and lumen/W is very less. So, it has a very less value of efficiency. Incase of fluorescent lamp also, the efficiency is less as the lumen/W is less. If we consider the power factor, ESL is better than fluorescent lamp. But the % THD incase of ESL is large. The best PF and %THD is incase of incandescent lamp but it has lesser efficiency. The presence of harmonics in electrical systems can be understood as a distortion and deviation in the current and voltage waveforms from ideal sinusoidal waveforms. They are represented in the form of a wave that has a frequency that is an integral multiple of the fundamental frequency. Harmonic current and voltage arises due to the presence of non- linear loads that are connected to a power system. Harmonics are harmful and unwanted. Harmonics overlay themselves on the fundamental waveform which is purely sinusoidal, cause distortion in it and change its magnitude. The ESLs need lesser amount of active power as compared to incandescent lamps (if luminous flux remains the same). ESL has low power consumption and longer lifetime[3]. Some examples of ESLs are compact fluorescent lamp(CFL), light emitting diode(LED) etc. They make use of electronic ballast. Due to it, their power factor (PF) is low. It means reactivepowerbecomeslow.Wemustchooseadevicewhichreducesthepower consumption and makes the power system stable. We study a CFL, an LED, a fluorescent lamp and an incandescent lamp. Figure 3 Simulation Results
Further work By comparing the various cases, we find that LED technology is good one in all. But there is a problem of harmonics seen. So, further work can be done to reduce harmonics incase of LED technology. Incase of CFL technology, we have to improve power factor as well as reduce harmonics. Inorder to carry out these, we can use a capacitor. A use of PI controller is also a good option. References [1] GulShahzad, Heekwon Yang, ArbabWaheed Ahmad and Chankil Lee,“Energy-Efficient Intelligent Street Lighting System Using Traffic-Adaptive Control”, IEEE Sensors Journal , Volume: 16, Issue: 13, July1, 2016 [2] R. Simanjuntak, P. Dupuis, L. Canale, N.I. Sinisuka, G.Zissis,“Power Quality of Energy SavingLampsunder WideVoltageVariations”,IndustryApplicationsSocietyAnnual Meeting, 2014 IEEE, 5-9 Oct. 2014. [3] F. G. Montoya and J. Castillo, ” Power Quality in modern lighting: comparison of LED, microLED and CFL lamps”, International Conference on Renewable Energies and Power Quality (ICREPQ’16) Madrid (Spain), 4th to 6th May, 2016. [4] J.P.A. Ioannidis, “Why most published research Findings are False,”PLoS Medicine, vol. 2, no. 8, 2005, pp. 696–701. [5] J. Buckheit and D.L. Donoho, “Wavelab and Reproducible Research,”Wavelets and Statistics,A. Antoniadis, ed., Springer-Verlag, 1995, pp. 55–81. [6] E. Arias-Castro et al., “Connect the Dots: How Many Random Points Can a Regular Curve Pass Through?,”Advancesin Applied Probability, vol. 37, no. 3, 2005, pp. 571–603.
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