A STUDY OF POWER FACTOR IMPACT ON ELECTRICAL INSTALLATIONS IN AJAOKUTA STEEL COMPANY LIMITED, NIGERIA

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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

CERTIFICATION                                                                                                                 ii

ACKNOWLEDGEMENT                                                                                                     iii

ABSTRACT                                                                                                                           iv

TABLE OF CONTENT                                                                                                         v

LIST OF FIGURES                                                                                                               xii

LIST OF TABLE                                                                                                                   xv

LIST OF ABBREVIATION                                                                                                  xvi

CHAPTER ONE: INTRODUCTION

CHAPTER TWO: LITERATURE REVIEW

2.3.0    Capacitance and Capacitor                                                                                         25

2.4.0    Phasor Representation of an Alternating Quantity                                                     26

2.7.2.0 Unpredictable Events                                                                                                 38

CHAPTER THREE: METHOD AND MATERIALS

CHAPTER FOUR: RESULT AND DISCUSSION

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

REFERENCES                                                                                                                     83

 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 2.11Phasor Representation of an Alternating Quantity27
  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 3.7Power Triangle64
  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

  1. 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

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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)