Modeling and Simulation of Compact Fluorescent Lamp for the Analysis and Mitigation of Harmonics Injection Into Power Distribution Network
Chapter One
Aim and Objectives
The aim of the research is modeling and simulation of compact fluorescent lamp for the analysis and mitigation of harmonics injection into power distribution network.
The objectives of the research are to:
- develop CFL model and determine its current and voltage total harmonics distortions being injected into power distribution
- develop analog passive harmonics filter network for the CFL harmonics injections
- validate results obtained through comparison with measured values from experimental fixed- bed.
CHAPTER TWO
LITERATURE REVIEW
Review of Fundamental Concepts
Some fundamental concepts related to this research work are reviewed. Some of the concepts discussed here are power system harmonics, power factor, support model equations relevant to the research and other aspects of significance to the research.
Power system
Electric power system is a network of electrical components installed to supply, transfer, and use electric power. Also, it is known as the grid (Weedy et al., 2012). A grid consists of three main sections: the generators that supply the power; the transmission system that carries the power from the generating centers to the load centers; and the distribution system that feeds the power to nearby homes and industries. Smaller power systems are also available in some industries, hospitals, commercial buildings and homes. The majority of these systems rely upon three-phase AC power (Kersting, 2012). A typical power system diagram is given in Figure 2.1 (Weedy et al., 2012)
Each section of the power system consists of many components interconnected to give the desired output. A problem associated with any of the sections means no supply to the consumer.
Harmonics in power system
One of the major power quality concerns is harmonic (Singh et al., 2014). The main objective of electricity utility is to deliver sinusoidal voltage at fairly constant magnitude throughout the power system. However, there are loads on the system that produce harmonics currents, this result in distorted current and voltage waveforms that adversely impact the system performance, (Singh et al., 2014).
Harmonics are considered by-products of modern electronic devices such as Personal Computers (PCs), laser printer, Television (TV) sets, battery chargers, Un-interrupted Power Supply (UPS) units, CFLs etc. These loads that are being powered by Switched-Mode Power Supply (SMPS) unit are referred to as nonlinear loads. They create harmonics by drawing current in abrupt short pulses. Any DN feeding nonlinear loads will contain some degree of harmonic frequencies (Sekaran & Anbalagan, 2008 andPourarab et al., 2011). Due to the rapidly increasing number of nonlinear loads in DN, the harmonic distortions ofcurrent and voltage increase (Singh and Singh, 2010). As the number of harmonics-producing loads at the consumer end increases over the years, it has become increasingly necessary to address their effects on the DN (Tripathy et al., 2010). The existence of harmonics that caused waveform distortion of the signal in electrical power system (EPS) is common, and its effect is harmless as long as it is maintained at the acceptable level of 8% for THDv and 3% for Individual Harmonic Distortion in voltage (IHDv) considering system with voltage level up to 69kV as recommended by IEEE Std. 519-2014 (Farooq et al., 2013). The limit for THDi is 20% and limits for Individual Harmonic Distortion in current (IHDi) is given in Table 2.1 (Farooq et al., 2013).
With rapid advancement of power electronics and electrical devices, the power system harmonics have attracts more attention of researchers. Power quality of DN is severely affected due to the flow of these generated harmonics. Harmonic currents generated by nonlinear loads can cause problems in the power system (Efe, 2015). Feng et al., (2013) attributed excessive heat in electrical appliances which is responsible for the reduction in the life span of the distribution transformer; increase in power consumption; reduction of system efficiency; lowering of the system power factor which increases monthly utility bills to harmonics in some countries. Harmonic Distortion (HD) is the degree to which a waveform deviates from its pure sinusoidal waveform as a result of the summation of all harmonic elements (Efe, 2015). While Total Harmonic Distortion (THD) is the summation of all harmonic components of the voltage or current waveform compared with the fundamental component of current or voltage. The Total Harmonic Distortion in Voltage (THDv) and Current (THDi) can be calculated using the following equation (Venkatesh et al., 2008 and Efe, 2015).
CHAPTER THREE
MATERIALS AND METHOD
Introduction
Details of the materials and methods used to model, simulate and analyze the compact fluorescent lamp harmonics emissions as well as methods of its injection mitigation are presented
Materials
The materials employed for the actualization of this research work are as follows:
Personal computer
LTspice CFL Simulations, FFT current and voltage harmonics analyses as well as display of the 3θ power and harmonics analyzer results were carried out using HP Notebook computer with the following specifications.
- Intel(R) Atom (TM) CPU
- 86 GHz processor.
- 00GB installed memory(RAM).
- 32-bit Operating System(OS).
Compact fluorescent lamp
The ircuit diagram of real CFL 15 W half spiral, white in color, pin type CFL was used for the research work. The CFL was numbered MD HS-15W B22 (220-240V 50/60Hz 0.15A) which was a product of YESIMODI, a company in China. The CFL was made in China. Lifespan of the lamp was put at 8,000 hrs for 4 hrs operation per day by the manufacturer.
CHAPTER FOUR
RESULTS AND DISCUSSION
Introduction
This chapter presents and discusses FFT harmonic analyses results obtained before and after implementation of the developed harmonics filter networks. Simplified FFT algorithm, LTspice, powergui software in MATLAB as well as experimental Fixed-bed was used for the harmonics analyses.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
Introduction
In this chapter, discussions on results and conclusion are presented. The entire dissertation is summarized in the conclusion. The scope of the work has been limited to simulation in visual environment. Meanwhile, recommendations for further work as well as limitations of the work are presented in this chapter.
Discussions on Results
The dissertation presented a step by step procedure for modeling and simulation of compact fluorescent lamp for the analysis and mitigation of harmonics injection into power distribution network. Three methods were used for the harmonics analysis. These were: simplified FFT harmonics analysis algorithm; LTspice; and Powergui software. The results obtained for THDi and THDv in relation to the fundamental current and voltage were: 135.50% and 35.43%; 130.13% and 33.64%; as well as 130.08% and 36.55% respectively. The results were observed to be in agreement with one another when compared. Laboratory test bed results were averagely 128.90% and 31.60% for THDi and THDv respectively. The fixed-bed results were compared with those obtained with the simplified FFT algorithm for validation.
Simulink models of the CFL circuit with series and shunt passive harmonics filter networks were also developed with a view to evaluating their performance in terms of the CFL harmonics emission reduction. The choice of the method of harmonic reduction was based on its simplicity. FFT harmonics analysis was carried out on the developed Simulink models of the CFL circuits with the filters on powergui in MATLAB. The results obtained in relation to the fundamental current and voltage were 9.54% and 5.00% for the THDi and THDv with the series filter; 3.64% and 0.09% were obtained with the shunt filter.
It was observed that the reductions of THD of the CFL were achieved with the analog series and shunt passive filters.
Conclusion
Compact fluorescent lamp has been the most widely used lighting device due its energy efficiency and other advantages such as cost effectiveness and long life span. The lamp is a nonlinear load. However, this type of lamp is associated with one major technical challenge and that is emission of harmonics. Harmonic is a multiple integer of fundamental frequency. Even though CFL harmonics injections may be considered small, but when large number is used in a power distribution network its effect will be as large harmonics source. Mitigation of this harmonics becomes very difficult once injected into the distribution network. There have been many research works on the analysis and mitigation of the injection of Harmonics into the power distribution network. However, the methods used were characterized by inherent in-accuracy, complexity and other challenges due to large number of assumptions, and high demands of computational efforts. Consequently, this research work modeled and simulated compact fluorescent lamp for the analysis and mitigation of harmonics injection into power distribution network. Results achieved are summarized in this chapter.
Significant Contributions of the Research
CFL Harmonics analysis using simplified FFT analysis algorithm is presented. The THDi and THDv obtained were 135.50% and 35.43%
CFL Harmonics analysis using LTspice software is presented. The THDi and THDv were found to be 130.13% and64%.
CFL Harmonics analysis using powergui software is presented. 135.08% and55% were obtained as THDi and THDv respectively.
CFL Harmonics injection mitigation using analog series and shunt passive filtersare presented. The THDi and THDv were reduced to 9.54% and 5.00% with the series filter network as well as 3.64% and 0.09% with the shunt filter.
Recommendations for Further Works
The following are recommended for further works.
- Develop CFL prototype with series and shunt filters and determine its current and voltage total harmonics
- Extend the research into other nonlinear loads such as fan, PC, etc with a view to mitigating the harmonics they
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