ABSTRACT
The increasing and stochastic nature of consumers’ demand on electricity brought about the need for alternative means of complimenting the existing energy demand. In this research work, a grid connected hybrid system was modeled to support and improve the power quantity of the Kaduna north existing network. Load profiling was done using Artificial Neural Network based on Bayesian regularization algorithm to determine one year load demand of the area under study. The load profiling was carried out and deficit power of 3.21MW was obtained which brought the need to augment the power from the grid using solar-hydro hybrid system. The developed hybrid system was interfaced to the grid via a step-up transformer and a phase locked loop was designed to synchronize the hybrid system with the grid. The solar photovoltaic system adopted the use of Solarex MSX64 using average solar radiation intensity of 653.45W/m2. The photovoltaic array consist of 50 parallel connected strings and each string consist of 80 series connected photovoltaic modules while two hydro turbines that employed the use of 1.5MW reaction turbine coupled with self-excited induction generator were used for hydropower system development. An average head of 6.04m and discharge of 25.6m3/s were used in design of the hydropower system. The developed hybrid system was implemented on a Matlab/Simulink environment. The output voltage of the solar photovoltaic cell was boosted using boost converter before connection to DC link bus bar while the AC voltage of the hydro system was converted to DC voltage using universal bridge converter before connecting to the DC link Bus bar. An inverter was used to convert the DC voltage of the hybrid system to AC voltage and a step-up power transformer was used to step the voltage to the utility grid voltage. Phase locked loop was designed to enable synchronization of the hybrid system with the grid. Based on the result obtained, the hydropower system produced 2.88MW and the solar photovoltaic system produced 330kW. The hybrid system was able to supplement a total power of 3.21MW to the grid. The developed model result was validated using a standard model results as contained in the work of Meshram et al (2013). The hybrid system modeled was able to carter for the deficit power from the grid and also improves the power quality and security of the grid.
TABLE OF CONTENTS
TITLE PAGE………………………………………………………………………………………i
DECLARATION ……………………………………………………………………………………………………………. ii
CERTIFICATION ………………………………………………………………………………………………………… .iii
DEDICATION ……………………………………………………………………………………………………………. ..iiv
ACKNOWLEDGEMENTS ……………………………………………………………………………………………… v
ABSTRACT ………………………………………………………………………………………………………………….. vi TABLE OF CONTENTS …….…………………………………………………………………vii APPENDICES…………. …….…………………………………………………………………xi LIST OF FIGURES ……….……………………………………………………………………..xii LIST OF TABLES……………………………………………………………………………….xv LIST OF ABBREVIATION…………………………………………………………………….xvi
CHAPTER ONE: GENERAL INTRODUCTION
1.1: General Background …………………………………………………………………………………………………. 1
1.2: Challenges Facing Nigeria Power System ……………………………………………………………………. 2
1.3: Kaduna Sub-Transmission Network ……………………………………………………………………………. 2 1.4: Problem Statement…………………………………………………………………………….4 1.5: Aim and Objectives……………………………………………………………………..……4
1.6: Methodology ……………………………………………………………………………………………………………. 5
17: Justification of Research …………………………………………………………………………………………….. 6
1.8: Dissertation Organization ………………………………………………………………………………………….. 6
viii
CHAPTER TWO: LITERATURE REVIEW
2.1: Introduction ……………………………………………………………………………………………………………… 7
2.1.1: Review of Foundamental Concepts ………………………………………………………………………….. 7
2.1.2: Hybrid System ……………………………………………………………………………………………………. 7
2.1.2.1: Solar Photovoltaic Power System Technology and Configuration ………………………….. 7
2.1.2.2 Sizing of the Solar Array ……………………………………………………………………………………. 8
2.1.3: Hydroelectric Power System ………………………………………………………………………………… 9
2.1.3.1: Types of Hydroelectric Power Plants and Turbines ………………………………………………. 9
2.1.3.2 Modeling of Hydroelectric Power System ………………………………………………………….. 11
2.1.4: Self-Excited Induction Generator (SEIG) …………………………………………………………….. 14
2.1.4.1: Modeling of Self –Excited Induction Generator (SEIG) ……………………………………… 15
2.1.5: DC-DC Boost Converter ……………………………………………………………………………………. 16
2.1.6: Universal Bridge Inverter …………………………………………………………………………………… 17
2.1.7: Phase Lock Loop ………………………………………………………………………………………………. 18
2.1.7.1: Principle of Operation of Phase Lock Loop ……………………………………………………….. 19
2.1.7.2: Modeling of Phase Lock Loop …………………………………………………………………………. 22
2.1.7.3: Stationary Reference Frame …………………………………………………………………………….. 24
2.1.8: Forecasting ………………………………………………………………………………………………………. 31
2.1.8.1: Bayesian Regularization Training Algorithm …………………………………………………….. 33
2.2: Review of Similar Works ………………………………………………………………………………………… 35
CHAPTER THREE: MATERIALS AND METHODS
3.1: Introduction ……………………………………………………………………………………………………………. 43
3.2: Load Profiling ………………………………………………………………………………………………………… 43
ix
3.3: Developed Hybrid Model ………………………………………………………………………………………… 46
3.4: PV Solar System Model …………………………………………………………………………………………… 46
3.4.1: Sizing of the Photovoltaic Array ……………………………………………………………………………. 47
3.4.1.1: Model of Photovoltaic Array ………………………………………………………………………………. 48
3.4.1.2 Simulink Photovoltaic Array Sub-System ……………………………………………………………… 49
3.4.2: Design of the Boost Converter……………………………………………………………………………….. 50
3.4.2.1: Design Specification ………………………………………………………………………………………….. 51
3.5 : Model of Hydropower System …………………………………………………………………………………. 53
3.5.1: Hydropower Design ……………………………………………………………………………………………… 53
3.6: Model of Hybrid System………………………………………………………………………………………….. 55
3.6.1: Design of Phase Lock Loop …………………………………………………………………………………… 57
3.7: Model of Cascaded System ……………………………………………………………………………………… 61
CHAPTER FOUR:RESULTS AND DISCUSSIONS
4.1: Introduction ……………………………………………………………………………………………………………. 63
4.2: Results of Load Profiling …………………………………………………………………………………………. 63
4.3: Result Based on Hybrid System ……………………………………………………………………………….. 64
4.3.1: Hydropower System …………………………………………………………………………………………….. 65
4.3.2: Solar Photovoltaic System …………………………………………………………………………………….. 66
4.4: Validation………………………………………………………………………………………………………………. 73
4.4: Discussion of Result ……………………………………………………………………………………………….. 77
CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS
5.1: Introduction ……………………………………………………………………………………………………………. 78
x
5.2: Conclusion …………………………………………………………………………………………………………….. 78
5.3:Recommendation for Further Work ……………………………………………………………………………. 79
5.4: Significant Contributions ……………………………………………………………………………………….. 79
5.4: Limitation ……………………………………………………………………………………………………………… 80
REFERENCES …………………………………………………………………………………………………………….. 81
CHAPTER ONE
GENERAL INTRODUCTION 1.1 General Background In order to move towards a sustainable existence in our critically energy dependent society, there is a continuing need to adopt environmentally sustainable methods for energy production. In Nigeria, as in most developing nations, the demand for sustainable energy is increasing due to population and developmental growth (Otun et al, 2012). Researches in this field have developed several methods of generating clean and affordable energy. Even though the use of fossil fuels for generation of electrical energy is more than the use of renewable sources, decreasing oil reserves in the world makes the potential for fossil fuels as a future resource of energy to be decreasing (Zehra and Muhsin, 2013). This leads to a significant interest in renewable energy sources therefore, making transition from fossil fuels towards renewable energy unavoidable (Zehra and Muhsin, 2013). The dependency on safe energy production system from renewable energy is increasing and gaining ground with the support from government policy around the world, especially with the instability of oil in the Middle East and the recent Fukushima nuclear disaster (Jungjohann and Rickerson, 2011). Renewable energy technologies offer the promise of clean, abundant energy gathered from self-renewing resources such as the sun, wind, water, earth and plants (Dorin et al, 2009). In most cases, one renewable energy system cannot fulfill the power requirement alone as it is intermittent in nature hence the solution is to hybridized the renewable energy systems (Meshram et al, 2013). To satisfy the power requirement, integration of the power grid is required. For supplying electric power in areas using this hybrid system, the power grid may be integrated. For the development of a system that will augment deficit of power, load forecasting is necessary.
2
1.2 Challenges Facing Nigeria Power System Nigeria power system is facing enormous challenges such as high-energy losses due to the physical deterioration of the transmission and distribution facilities, inadequate metering system, increase in illegal connection, manpower constraints and inadequate support facilities, high cost of electricity production, inadequate basic industries to service the power sector, poor billing system, poor settlements of bills by consumers and low available capacity (Nasir, 2009). These factors are affecting the performance of the power sector both technically and economically.
1.3 Kaduna Sub-Transmission Network
Kaduna sub-transmission network is a network diagram of the injection substations of both the 33kV and 11kV Feeders in Kaduna north. The network comprises of one transmission station (Mando) feeding the five injection substations in Kaduna north. The five injection substations are Kawo injection substation, Dawaki injection substation, Abakpa injection substation, Mogadishu injection substation and Rigasa injection substation. Mando transmission station does not only feed the five injection substations in Kaduna north but also supply power to other substations outside Kaduna. Four out of the five injection substations are being fed by Mando transmission station while the Mogadishu is being fed by both Mando transmission station and 132kV power generation station. Figure 1.1 shows the Kaduna sub-transmission network.
3
2 X1 5M VA ,
3 3 / 1 1 KV TX F.
30MVA,
132/33KV
TXF.
30MVA,
132/33KV
TXF.
(Unsoa ked)
15MVA,
132/11KV
TXF.
60MVA,
132/33KV
TXF.
60MVA,
132/33KV
TXF.
60MVA,
132/33KV
TXF.
60MVA,
132/33KV
TXF.
60MVA,
132/33KV
TXF.
2 X1 5M V A ,
3 3 / 1 1 KV TX F.
2X1 5M VA,
3 3 / 1 1K V TXF.
2 X1 5M V A,
3 3 / 1 1 KV TXF.
2X 1 5M V A,
3 3 /1 1KV TXF.
2 . 5M VA ,
3 3 /1 1KV TXF.
N EC
Figure 1.1: Kaduna Sub-Transmission Network (Catalog on Planning and Construction PHCN,
2012)
4
Dawaki injection substation is one of the most important substations in Kaduna metropolis. This is because it supplies power to many important areas such as Government house, Nigerian television authority (N.T.A) transmission station, liberty radio, independent national electoral commission (INEC) office, national youth service corps (NYSC) secretariat among others. 1.4 Problem Statement A number of research works had been conducted to augment the deficit of power in the grid which is due to increasing demand of energy and insufficient generation. Power from the grid was not sufficient due to network expansion, urbanization, migration and greater demand of power by the consumers and no plan for increase in generation by the utility was made. This results in load shading by the utility in order to balance the generation with the load. This decreases the power quality and security of the utility grid and brought the need for alternative means of power generation to support the utility grid. In this work, load profiling was done using artificial neural network based on Bayesian regularization algorithm. The model was developed putting in cognizance the effect of environmental condition which includes temperature, relative humidity, rainfall, wind speed, solar radiation and sunshine hours. Power deficit from the utility grid was augmented by developing a grid connected solar-hydro hybrid system. 1.5 Aim and Objectives The aim of this research work is to develop a grid connected hybrid power system that will augment the power supply to consumers. In order to achieve this aim, the following itemized objectives are met:
1. Determination of the load profiling using Artificial Neural Networks (ANN) based on past trend of data;
5
2. Development of a solar-hydro hybrid system using MATLAB/Simulink Environment;
3. Integrating the developed hybrid system with the utility grid.
1.6 Methodology The sequential steps adopted for the development of the grid connected Solar-Hydro hybrid system are: 1. Collection of three years (3) data from relevant authorities: i. Load Demand from Transmission Company of Nigeria (T.C.N) ii. River flow rate and height from Kaduna state water board iii. Temperature, relative humidity, rainfall, wind speed, solar radiation and sunshine hours from National Meteorological Agency (NIMET) 2. Based on the data collected in item 1 above, a load profiling was carried out to project one year load demand i. Development of Artificial Neural Network model based on Bayesian regularization algorithm; ii. Training, testing and validation of the developed model using utility data; iii. Forecasting the future load demand using collected data. 3. Design of solar photovoltaic module configuration; 4. Development of a hydro system using self-induction generation; 5. Development of a hybrid system (model) using items 3 and 4 above on a Simulink interface; 6. Interfacing the hybrid system with the utility via an phase lock loop;
7. Validating the developed model with other standard works.
6
1.7 Justification of Research The amount of power allocated to Kaduna State has been shared to different areas of the State is less than the load demand. This in turn lead to load shading by the utility to balance the load demand with the allocated power. The load shading affects the quality, quantity and security of the system. This brought the need to develop a system capable of supplementing the allocated power to Kaduna North from the grid. Many researchers worked on developing a system to augment the deficit of power in the grid without considering the future load demand. Most of the literatures only considered limited renewable energy sources for supplementing the grid power supply, hence, the renewable energy sources available are not fully exploited. This research work addresses these problems by first forecasting the future load demand for Kaduna North and then developing a Solar-Hydro hybrid generation system to argument the deficit power obtained from the load forecast. 1.8 Dissertation Organization In chapter one, general background and the concept of hybrid system is presented, followed by challenges facing Nigeria power system. In chapter two, a concise review of the fundamental concepts and literature review on hybrid system are presented. In chapter three, methods and materials are presented which comprise the mathematical models and Simulink models of the hybrid system. In chapter four, result was presented based on the analysis of the load profiling and solar-hydro hybrid model. Chapter five presents the conclusion, recommendation and limitations of the entire research work.
IF YOU CAN'T FIND YOUR TOPIC, CLICK HERE TO HIRE A WRITER»
