ABSTRACT
Power factor is related to power flow in electrical systems and measures how effective an electrical power system is used. In order to efficiently use a power system, the power factor should be as close to unity as possible. This implies that the flow of reactive power should be kept to a minimal. Maintaining a high power factor is crucial to obtaining the best possible economic advantage for both Utilities and Industrial users. Operating a power system at a low power factor is a concern for both electrical utility and industry since it increases the magnitude of current in the system which may damage or shorten the life span of the equipment and also increase copper loss which is capable of lowering the system efficiency due to increase in reactive power. Industrial loads are mostly inductive and hence operate at low power factor. Several methods can be used for improving power factor in order to reduce the reactive power (kVA) demands of the load and power loss from the power supply system. Therefore the study of the power factor impact on the electrical installations of Ajaokuta power system is to analyze the effect of improving power factor of its electrical installation network beyond 0.8 being the power factor of various induction motors as investigated using the recirculating system No. 3 (Pump House No 3). The research approach used to implement this study is through simulation and calculations considering the use of bank of capacitors because it is the most common method of power factor correction. The result of the three investigations carried out shows that when power factor is improved there will be a reduction in the energy charges to the Ajaokuta steel plant. The plant was able to save 2 million one hundred and seventy five thousand five hundred and fifty eight naira (2,175,558) only. This amount was just for one substation out of 400 substations in the plant.
CONTENTS
Page
TITLE PAGE i
TABLE OF CONTENT v
LIST OF FIGURES xii
LIST OF TABLE xv
LIST OF ABBREVIATION xvi
- Background To The Study 1
- Justification Of The Study 5
- Objective Of The Study 7
- Scope And Limitation 7
- Scope 7
- Limitation 7
- Methodology 8
- Thesis Arrangement 11
CHAPTER TWO: LITERATURE REVIEW
- Power System 12
- Types Of Power 14
- Power System Loads 15
- Power Factor 17
- Definitions 19
- Meaning of Power Factor 20
- Relevance of Power Factor 21
- Effects of Power Factor 23
2.3.0 Capacitance and Capacitor 25
2.4.0 Phasor Representation of an Alternating Quantity 26
- Phasor Representation of Quantities Differing in Phase
- Addition and Subtraction of Sinusoidal Alternating Quantities 28
- Subtraction of Phasor 29
- Phasor Additions 30
- Important Formulae 32
- Understanding Power Factor 34
- Typical Utility Billing Structure 36
- Low Power Factor 37
- Power Quality 37
- Sources of Power Quality Disturbance 38
2.7.2.0 Unpredictable Events 38
- Point of Supply (Generation)
- The Transmission System 39
- The Distribution System 39
- The Customer 39
- Manufacturing Regulation 40
- Standard 40
- Operating Conditions 40
- Line Voltage 41
- Resistive Loads 41
- Inductive Load 42
- Cos ∅ In Pf 42
- Improving Power Factor 43
- Advantages of Improved Power Factor 43
- Disadvantages of Low Power Factor 44
- Effects of Low Power Factor 46
- Causes of Low Power Factor 47
- Methods of Power Factor Correction 48
- Static Capacitor 49
- Synchronous or High Power Factor Machine 52
- Synchronous Motors 52
- Synchronous Condensers 53
- Phase Advancer 55
- Synchronous-Induction Motor 56
- High Power Factor Motors 56
- Location of Power Factor Correction Equipment 56
- The Transmission System 39
CHAPTER THREE: METHOD AND MATERIALS
- Test and Experiment Method 57
- Site and Location of Study 57
- The Experimental Procedure 60
- Capacitors 61
- Advantages of Capacitor 61
- Proecdure 63
- Measurement and Calculations 63
- Alternatively 63
- Construction 64
- How to Calculate the Size of Capacitor 66
- Experiment No: 1 66
- Experiment No: 2 68
- Experiment No: 3 69
CHAPTER FOUR: RESULT AND DISCUSSION
- Result of Experiment No: 1 73
- Analysis of Experiment No: 1 73
- Result of Experiment No: 2 74
- Graph of Experiment No: 2 75
4.5.1 Graph of Experiment No: 3 before Improving Power Factor 76
4.6 Analysis of Experiment No: 3 79
- Findings of the Study 79
- Contribution to Knowledge 80
CHAPTER FIVE: CONCLUSIONS AND RECOMMENDATION
- Conclusions 81
LIST OF FIGURES | ||
Fig 1.1 | Electronic Configuration of A Hydrogen Atom | Page 3 |
Fig 1.2 | 132kV Transmission Substation Power Network of Ajaokuta | |
Steel Company | 9 | |
Fig 1.3 | Experimental Block Diagram | 10 |
Fig 1.4 | Research Stage By Stage Analysis of Power Factor | 10 |
Fig 2.1 | Simple DC Circuit | 2 |
Fig 2.2 | A/C Waveform | 13 |
Fig 2.3 | Negative Phase Shift | 13 |
Fig 2.4 | Positive Phase Shift | 14 |
Fig 2.5 | Purely Reactive Circuit | 16 |
Fig 2.6 | Purely Inductive Circuit | 16 |
Fig 2.7 | Reactive and Inductive Circuit | 17 |
Fig 2.8 | The Power Triangle | 18 |
Fig 2.9 | Graphical Representation of Power Factor Relationship | 21 |
Fig 2.10 | Phasor Representation of an A/C Quantity | 26 |
Fig 2.11 | Phasor Representation of an Alternating Quantity | 27 |
Fig 2.12 | Addition of Phasors | 29 |
Fig 2.13 | Phasor Diagram and Waveform Representing Voltage and Current | 30 |
Fig 2.14 | Addition of Phasor Representation | 30 |
Fig 2.15 | Diagrammatic Representation of Phasor Subtraction | 32 |
Fig 2.16 | Power Factor Triangle | 43 |
Fig 2.17 | Leading Power Factor | 43 |
Fig 2.18 | Star Connected Capacitors | 49 |
Fig 2.19 | Delta Connected Capacitors | 49 |
Fig 2.20 | Series Connection of Capacitors | 50 |
Fig 2.21 | Parallel Connection of Transformer to Reduce Reaction | 51 |
Fig 2.22 | Phasor Diagram | 53 |
Fig 3.1 | Location of Ajaokuta on World Map | 58 |
Fig 3.2 | 132KV Ajaokuta Transmission Substation | 59 |
Fig 3.3 | Experimental Procedure | 60 |
Fig 3.4 | Experimental Activities | 60 |
Fig 3.5 | Individual Motor Compensation | 62 |
Fig 3.6 | Power Factor Correction Unit | 63 |
Fig 3.7 | Power Triangle | 64 |
Fig 3.8 | Leading Power Factor Correction Triangle | 65 |
Fig 3.9 | Lagging Power Factor Correction Triangle | 65 |
Fig 3.10 | Transmission System without the Capacitor Bank | 67 |
Fig 3.11 | Transmission System with Capacitor Bank | 68 |
Fig 3.12 | Transmission System without Capacitor for Experiment No: 3 | 70 |
Fig 3.13 | Transmission System with Capacitor for Experiment No: 3 | 71 |
Fig 4.1 | Power Factor against Motor Load Factor | 75 |
Fig 4.2 | Power Factor against Time before Improvement | 76 |
Fig 4.3 | Reactive Power against Time | 77 |
Fig 4.4 | Apparent Power against Time | 77 |
Fig 4.5 | Real Power against Time | 78 |
Fig 4.6 | Current against Time | 78 |
LIST OF TABLES | ||
Table 2.1 | Deducing the Power Parameters | Page 15 |
Table 2.2 | Typical Un-Improve Power Factor by Industry | 35 |
Table 3.1 | Record of Activities at Pump House No: 3 Between April 2015 and | |
May 2017 | 68 | |
Table 3.2 | Load and the Power Factor Value | 69 |
Table 3.3 | Before Correction | 72 |
Table 3.4 | After Correction | 72 |
Table 4.1 | Result of Experiment No:1 | 73 |
Table 4.2 | Load and the Power Factor Value | 74 |
LIST OF ABBREVIATIONS AND SYMBOLS
∅ Phi
A Ampere
AC Alternating Current
ASCL Ajaokuta Steel Company Limited C Capacitance
CT current Transformer
DS Distribution Station
EMF Electromagnetic force
f frequency
Fig Figure
h Hour
H.V High Voltage
Hz Hertz
- Current
- Joules
kV kilovolt
kVA kilovolt Ampere
kVAR kilovolt Ampere (reactive)
kW kilowatt
LV Low voltage
NERC National Electricity Regulatory Commission Ɵ Phase Angle
- True/Active/Real Power (KW)
P.F Power Factor
PFC Power Factor Correction
Ph3 Pump House No.3
- Reactive/inductive KVAR
RCS Recirculating System
RMS Root Mean Square
S Apparent Power KVA
S seconds
TCN Transmission Company of Nigeria
TS Transformer Station
V Volts
VT or PT voltage Transformer or Potential Transformer W Watts
μF micro farad
𝜋 Pi
xv
CHAPTER ONE INTRODUCTION
Background to the Study
The background of any study provides the fundamental framework and basic concepts for the true knowledge and proper understanding of the study, through presentation of facts and qualitative analysis, with the basic principles and laws paramount to the study. In the course of this study, the center of attention is power factor which is a function of energy. These frame work or the fundamental principles and laws borders on the scientific study and universal concepts of matter, space and time in relation with man and his immediate environment (Mohammed, 2013).
Scientific investigation of the characteristic nature and behavioural pattern of matter, with reference to space and time, often reveals that the study of energy which is the ability to do work. The source of this energy is the sun. This primary form of energy is called solar energy. Scientific investigations provide evidences to the study of energy. The facts are preserved by the law of its conservation, which states that energy cannot be created nor destroyed but can only be changed from one form to another or transferred from one point of location to another (Ubi, 2013). The unit of energy is Joule (J) i.e. Newton-meter (N-m). Energy generated or expended per second is known as power. The unit of power is Joule per second (J/s), Watts (W), Volt-ampere (VA), or Volt-ampere reactive (VAR). These units define the various types of electrical power, which are: Real or Active power in Watts (W),
Reactive power in volt, ampere-reactive (VAR), Apparent power measured in Volt-ampere (VA) which is a combination of both true and reactive power.
The effectiveness of ac power is determined by power factor. It is a function of the phase angle of ac current or voltage. Usually, power factor P.F, has a value range from 0 to 1. That is 0 ≤
P.F ≤ 1. The closer the value of P.F to unity, the more efficient the system becomes. It is the ratio of the active power to apparent power given by,
𝑃. 𝐹 = 𝑇𝑟𝑢𝑒(𝑜𝑟 𝑎𝑐𝑡𝑖𝑣𝑒)𝑃𝑜𝑤𝑒𝑟,𝑊
𝐴𝑝𝑝𝑎𝑟𝑒𝑛𝑡 𝑃𝑜𝑤𝑒𝑟,𝑉𝐴
= 𝑐𝑜𝑠 ∅ (1.1)
where, Ø = Phase angle of the electrical quantity (i.e. voltage or current).
The knowledge of the primary concepts of energy forms the basic understanding of electricity and the power factor with its implications, relevance, problems and corrective measures. There are different types of energy, and these are: Solar, Electrical, Chemical, Mechanical, Potential, Kinetic, Internal, Atomic, Nuclear, Heat, Light, Sound, and Electronic (Constantin, 2011). In the content of this study, electrical energy is the major focus due to its relationship with the subject matter which is power factor problems, investigation, analysis, implication and correction. As far as power system delivery is concerned the power factor of electrical generation, transmission and distribution system is of great relevance. It is a function of electrical charges. These charges however, move or flow as particles called electrons.
The flow or movement of these particles is known as current. Electrons are sub divisional particles of an atom. This atom according to atomic theory is the smallest particle of an element or a substance that can take part in any chemical reaction. An element is a substance that can exist separately. Chemical reaction is the chemical combination or disintegration. That is, chemical fusion or fusion of two or more elements or substances to form a compound. The entire study of electricity depends on the process of migration, movement, transfer or flow of electrons from one particular atom of an element or substance to another and the electrical force causing the flow or substance. Figure 1.1 shows the electronic configuration of Hydrogen (H)