The quality of power is very necessary now days and cannot be avoided at all.

engineering

Description

Abstract

The quality of power is very necessary now days and cannot be avoided at all. The power quality is very important for every instruments used in daily life. From generation of power to the distribution of power, the quality has to be maintained at every part of the system. Variation in power quality can leads to the fault in the system and sometimes it causes to the major fault and destruct the electrical equipments. Lightning is major thing which affects the quality of power as it can cause the power failure, voltage transient, sags, swells, variation in the power angle and also affects the frequency of the system.  


Here we, study the basics of the lightning and its consequences to our power system and also the configuration and working as well of the lightning rod. Here, how a lightning rod protects our system from lightning and it affects our power system. We also study about the different type of configuration of the lightning rod and their working principal as well.


Table of content –

Table of figure - 4

Acknowledgement 5

INTRODUCTION 6

LIGHTNING: ISSUES TO POWER QUALITY 8

Introduction 8

Lightning discharge 9

Physics of lightning 13

Effect of lightning strike on objects 19

Electrical 19

Thermal 20

Mechanical 20

Effect of lightning strike on electrical installations 20

Basics of lightning rod and surge arrester 27

How Lightning effects the Power System Stability 35

Improved lightning rod configurations 37

Power quality 43

Result 44

Conclusion 48

Reference 49


Table of figure -

Figure 1-over voltage and under voltage 8

Figure 2 –different issues with power quality 9

Figure 3 – lightning discharge 10

Figure 4 – cloud to earth discharge 11

Figure 5 –discharge waveforms 12

Figure 6 –earth to cloud discharge 13

Figure 7 – earth to cloud waveforms 14

Figure 8 –lightning mechanism 15

Figure 9 – current to time waveform 16

Figure 10 - Discharge through mast 19

Figure 11 –ground electric field 20

Figure 12 – resistive coupling 22

Figure 13 –inductive coupling 22

Figure 14 –capacitive coupling 23

Figure 15 –transmission tower 30

Figure 16 –grounding system 31

Figure 17 –lightning rods 31

Figure 18 –time relative to return stroke 32

Figure 19 –transient overvoltage 38

Figure 20 –waveform during stroke 38

Figure 21 –improved lightning rod 40

Figure 22 –rod tip diameter vs height 41

Figure 23 – rod installation 41

Figure 24 – current waveforms of different rods 1 43

Figure 25 - current waveforms of different rods 2 44

Figure 26 -resulted waveform 47

Figure 27- current surge (left) and protected current surge (right) 48

Figure 28-lightning performance analysis of overhead transmission lines 48

Figure 29- transient behavior of voltage drop across insulator 49

Figure 30- transient behavior of voltage drop across insulator with grounding sw 49


Acknowledgement



INTRODUCTION

Electrical power quality is basically the good functioning of the voltage, frequency and waveform and good power quality are often defined as wanted and smooth fluctuation free supply voltage that stays within the wanted range and steady, smooth a.c. frequency of the prescribed value.

 The issues between the power quality what comes out of an electrical outlet and therefore the load used into it. The term is employed to explain electrical power that drives an electrical load and therefore the load's ability to function properly. Without the right power, an device may malfunction, fail or not operate in the least. There are some ways during which electrical power are often of poor quality and lots of more causes of such poor quality power.

While "power quality" may be a convenient term for several, it's the standard of the voltage—rather than power or electric current—that is really described by the term. Power is just the flow of energy and therefore the current demanded by a load is essentially uncontrollable Due to highly  increase in needs of person , the power generation system surfaces a shortage of main energy sources like fossil fuels because the demand is growing day by day without a rise in substitute generation resources. These ins and outs may have strained the facility system to function beyond the potential it's constructed to be handled originally. This carries the chief issue of transient stability of power grid in apprehension. If some generators are functioning far-off from the load centers, then the matter of transient stability will prime to a main disturbance which may be a hazard to the supply security also as grid operators will find it problematic for the daily operations of power grid. Transient stability refers to intense transfer of power through cable without dropping stability.

Power quality is a major issue now days. As the demand of power increases rapidly the quality of the power is becoming the major issue for all countries whether they are small countries or big , developed or the developing countries. 


DEVIATION IN POWER QUALITY

Voltage

Variations shows in the ⦁ peak voltage are important to different types of equipment.

The peak voltage increased to the rated voltage by 10 to 80% for 1 minute, that’s called swell.

Voltage deviation is the major issue to the electric power quality.


Frequency

Variations in the ⦁ frequency.

Nonzero low frequency ⦁ impedance occurs when a load draws high power.

Nonzero high frequency impedance occurs when a load demands large current, then suddenly stops demanding it, there will be a dip or ⦁ spike in the voltage.


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